Граф коммитов

866 Коммитов

Автор SHA1 Сообщение Дата
Sean Christopherson 2a49f61dfc KVM: Ensure validity of memslot with respect to kvm_get_dirty_log()
Rework kvm_get_dirty_log() so that it "returns" the associated memslot
on success.  A future patch will rework memslot handling such that
id_to_memslot() can return NULL, returning the memslot makes it more
obvious that the validity of the memslot has been verified, i.e.
precludes the need to add validity checks in the arch code that are
technically unnecessary.

To maintain ordering in s390, move the call to kvm_arch_sync_dirty_log()
from s390's kvm_vm_ioctl_get_dirty_log() to the new kvm_get_dirty_log().
This is a nop for PPC, the only other arch that doesn't select
KVM_GENERIC_DIRTYLOG_READ_PROTECT, as its sync_dirty_log() is empty.

Ideally, moving the sync_dirty_log() call would be done in a separate
patch, but it can't be done in a follow-on patch because that would
temporarily break s390's ordering.  Making the move in a preparatory
patch would be functionally correct, but would create an odd scenario
where the moved sync_dirty_log() would operate on a "different" memslot
due to consuming the result of a different id_to_memslot().  The
memslot couldn't actually be different as slots_lock is held, but the
code is confusing enough as it is, i.e. moving sync_dirty_log() in this
patch is the lesser of all evils.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:25 +01:00
Sean Christopherson 0dff084607 KVM: Provide common implementation for generic dirty log functions
Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG
for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code.
The arch specific implemenations are extremely similar, differing
only in whether the dirty log needs to be sync'd from hardware (x86)
and how the TLBs are flushed.  Add new arch hooks to handle sync
and TLB flush; the sync will also be used for non-generic dirty log
support in a future patch (s390).

The ulterior motive for providing a common implementation is to
eliminate the dependency between arch and common code with respect to
the memslot referenced by the dirty log, i.e. to make it obvious in the
code that the validity of the memslot is guaranteed, as a future patch
will rework memslot handling such that id_to_memslot() can return NULL.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:24 +01:00
Sean Christopherson 163da372de KVM: Clean up local variable usage in __kvm_set_memory_region()
Clean up __kvm_set_memory_region() to achieve several goals:

  - Remove local variables that serve no real purpose
  - Improve the readability of the code
  - Better show the relationship between the 'old' and 'new' memslot
  - Prepare for dynamically sizing memslots
  - Document subtle gotchas (via comments)

Note, using 'tmp' to hold the initial memslot is not strictly necessary
at this juncture, e.g. 'old' could be directly copied from
id_to_memslot(), but keep the pointer usage as id_to_memslot() will be
able to return a NULL pointer once memslots are dynamically sized.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:23 +01:00
Sean Christopherson e96c81ee89 KVM: Simplify kvm_free_memslot() and all its descendents
Now that all callers of kvm_free_memslot() pass NULL for @dont, remove
the param from the top-level routine and all arch's implementations.

No functional change intended.

Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:22 +01:00
Sean Christopherson 5c0b4f3d5c KVM: Move memslot deletion to helper function
Move memslot deletion into its own routine so that the success path for
other memslot updates does not need to use kvm_free_memslot(), i.e. can
explicitly destroy the dirty bitmap when necessary.  This paves the way
for dropping @dont from kvm_free_memslot(), i.e. all callers now pass
NULL for @dont.

Add a comment above the code to make a copy of the existing memslot
prior to deletion, it is not at all obvious that the pointer will become
stale during sorting and/or installation of new memslots.

Note, kvm_arch_commit_memory_region() allows an architecture to free
resources when moving a memslot or changing its flags, e.g. x86 frees
its arch specific memslot metadata during commit_memory_region().

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:22 +01:00
Sean Christopherson 9d4c197c0e KVM: Drop "const" attribute from old memslot in commit_memory_region()
Drop the "const" attribute from @old in kvm_arch_commit_memory_region()
to allow arch specific code to free arch specific resources in the old
memslot without having to cast away the attribute.  Freeing resources in
kvm_arch_commit_memory_region() paves the way for simplifying
kvm_free_memslot() by eliminating the last usage of its @dont param.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:20 +01:00
Sean Christopherson cf47f50b5c KVM: Move setting of memslot into helper routine
Split out the core functionality of setting a memslot into a separate
helper in preparation for moving memslot deletion into its own routine.

Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:19 +01:00
Sean Christopherson 71a4c30bf0 KVM: Refactor error handling for setting memory region
Replace a big pile o' gotos with returns to make it more obvious what
error code is being returned, and to prepare for refactoring the
functional, i.e. post-checks, portion of __kvm_set_memory_region().

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:19 +01:00
Sean Christopherson bd0e96fdc5 KVM: Explicitly free allocated-but-unused dirty bitmap
Explicitly free an allocated-but-unused dirty bitmap instead of relying
on kvm_free_memslot() if an error occurs in __kvm_set_memory_region().
There is no longer a need to abuse kvm_free_memslot() to free arch
specific resources as arch specific code is now called only after the
common flow is guaranteed to succeed.  Arch code can still fail, but
it's responsible for its own cleanup in that case.

Eliminating the error path's abuse of kvm_free_memslot() paves the way
for simplifying kvm_free_memslot(), i.e. dropping its @dont param.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:18 +01:00
Sean Christopherson 414de7abbf KVM: Drop kvm_arch_create_memslot()
Remove kvm_arch_create_memslot() now that all arch implementations are
effectively nops.  Removing kvm_arch_create_memslot() eliminates the
possibility for arch specific code to allocate memory prior to setting
a memslot, which sets the stage for simplifying kvm_free_memslot().

Cc: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:17 +01:00
Sean Christopherson 13f678894b KVM: Don't free new memslot if allocation of said memslot fails
The two implementations of kvm_arch_create_memslot() in x86 and PPC are
both good citizens and free up all local resources if creation fails.
Return immediately (via a superfluous goto) instead of calling
kvm_free_memslot().

Note, the call to kvm_free_memslot() is effectively an expensive nop in
this case as there are no resources to be freed.

No functional change intended.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:15 +01:00
Sean Christopherson 13ea525517 KVM: Reinstall old memslots if arch preparation fails
Reinstall the old memslots if preparing the new memory region fails
after invalidating a to-be-{re}moved memslot.

Remove the superfluous 'old_memslots' variable so that it's somewhat
clear that the error handling path needs to free the unused memslots,
not simply the 'old' memslots.

Fixes: bc6678a33d ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update")
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-03-16 17:57:14 +01:00
Marc Zyngier 1f03b2bcd0 KVM: Disable preemption in kvm_get_running_vcpu()
Accessing a per-cpu variable only makes sense when preemption is
disabled (and the kernel does check this when the right debug options
are switched on).

For kvm_get_running_vcpu(), it is fine to return the value after
re-enabling preemption, as the preempt notifiers will make sure that
this is kept consistent across task migration (the comment above the
function hints at it, but lacks the crucial preemption management).

While we're at it, move the comment from the ARM code, which explains
why the whole thing works.

Fixes: 7495e22bb1 ("KVM: Move running VCPU from ARM to common code").
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Tested-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/318984f6-bc36-33a3-abc6-bf2295974b06@huawei.com
Message-id: <20200207163410.31276-1-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-12 12:19:35 +01:00
Zhuang Yanying 7df003c852 KVM: fix overflow of zero page refcount with ksm running
We are testing Virtual Machine with KSM on v5.4-rc2 kernel,
and found the zero_page refcount overflow.
The cause of refcount overflow is increased in try_async_pf
(get_user_page) without being decreased in mmu_set_spte()
while handling ept violation.
In kvm_release_pfn_clean(), only unreserved page will call
put_page. However, zero page is reserved.
So, as well as creating and destroy vm, the refcount of
zero page will continue to increase until it overflows.

step1:
echo 10000 > /sys/kernel/pages_to_scan/pages_to_scan
echo 1 > /sys/kernel/pages_to_scan/run
echo 1 > /sys/kernel/pages_to_scan/use_zero_pages

step2:
just create several normal qemu kvm vms.
And destroy it after 10s.
Repeat this action all the time.

After a long period of time, all domains hang because
of the refcount of zero page overflow.

Qemu print error log as follow:
 …
 error: kvm run failed Bad address
 EAX=00006cdc EBX=00000008 ECX=80202001 EDX=078bfbfd
 ESI=ffffffff EDI=00000000 EBP=00000008 ESP=00006cc4
 EIP=000efd75 EFL=00010002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
 ES =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
 CS =0008 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
 SS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
 DS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
 FS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
 GS =0010 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
 LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
 TR =0000 00000000 0000ffff 00008b00 DPL=0 TSS32-busy
 GDT=     000f7070 00000037
 IDT=     000f70ae 00000000
 CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
 DR6=00000000ffff0ff0 DR7=0000000000000400
 EFER=0000000000000000
 Code=00 01 00 00 00 e9 e8 00 00 00 c7 05 4c 55 0f 00 01 00 00 00 <8b> 35 00 00 01 00 8b 3d 04 00 01 00 b8 d8 d3 00 00 c1 e0 08 0c ea a3 00 00 01 00 c7 05 04
 …

Meanwhile, a kernel warning is departed.

 [40914.836375] WARNING: CPU: 3 PID: 82067 at ./include/linux/mm.h:987 try_get_page+0x1f/0x30
 [40914.836412] CPU: 3 PID: 82067 Comm: CPU 0/KVM Kdump: loaded Tainted: G           OE     5.2.0-rc2 #5
 [40914.836415] RIP: 0010:try_get_page+0x1f/0x30
 [40914.836417] Code: 40 00 c3 0f 1f 84 00 00 00 00 00 48 8b 47 08 a8 01 75 11 8b 47 34 85 c0 7e 10 f0 ff 47 34 b8 01 00 00 00 c3 48 8d 78 ff eb e9 <0f> 0b 31 c0 c3 66 90 66 2e 0f 1f 84 00 0
 0 00 00 00 48 8b 47 08 a8
 [40914.836418] RSP: 0018:ffffb4144e523988 EFLAGS: 00010286
 [40914.836419] RAX: 0000000080000000 RBX: 0000000000000326 RCX: 0000000000000000
 [40914.836420] RDX: 0000000000000000 RSI: 00004ffdeba10000 RDI: ffffdf07093f6440
 [40914.836421] RBP: ffffdf07093f6440 R08: 800000424fd91225 R09: 0000000000000000
 [40914.836421] R10: ffff9eb41bfeebb8 R11: 0000000000000000 R12: ffffdf06bbd1e8a8
 [40914.836422] R13: 0000000000000080 R14: 800000424fd91225 R15: ffffdf07093f6440
 [40914.836423] FS:  00007fb60ffff700(0000) GS:ffff9eb4802c0000(0000) knlGS:0000000000000000
 [40914.836425] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [40914.836426] CR2: 0000000000000000 CR3: 0000002f220e6002 CR4: 00000000003626e0
 [40914.836427] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 [40914.836427] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 [40914.836428] Call Trace:
 [40914.836433]  follow_page_pte+0x302/0x47b
 [40914.836437]  __get_user_pages+0xf1/0x7d0
 [40914.836441]  ? irq_work_queue+0x9/0x70
 [40914.836443]  get_user_pages_unlocked+0x13f/0x1e0
 [40914.836469]  __gfn_to_pfn_memslot+0x10e/0x400 [kvm]
 [40914.836486]  try_async_pf+0x87/0x240 [kvm]
 [40914.836503]  tdp_page_fault+0x139/0x270 [kvm]
 [40914.836523]  kvm_mmu_page_fault+0x76/0x5e0 [kvm]
 [40914.836588]  vcpu_enter_guest+0xb45/0x1570 [kvm]
 [40914.836632]  kvm_arch_vcpu_ioctl_run+0x35d/0x580 [kvm]
 [40914.836645]  kvm_vcpu_ioctl+0x26e/0x5d0 [kvm]
 [40914.836650]  do_vfs_ioctl+0xa9/0x620
 [40914.836653]  ksys_ioctl+0x60/0x90
 [40914.836654]  __x64_sys_ioctl+0x16/0x20
 [40914.836658]  do_syscall_64+0x5b/0x180
 [40914.836664]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
 [40914.836666] RIP: 0033:0x7fb61cb6bfc7

Signed-off-by: LinFeng <linfeng23@huawei.com>
Signed-off-by: Zhuang Yanying <ann.zhuangyanying@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-02-05 15:27:46 +01:00
Paolo Bonzini 4cbc418a44 Merge branch 'cve-2019-3016' into kvm-next-5.6
From Boris Ostrovsky:

The KVM hypervisor may provide a guest with ability to defer remote TLB
flush when the remote VCPU is not running. When this feature is used,
the TLB flush will happen only when the remote VPCU is scheduled to run
again. This will avoid unnecessary (and expensive) IPIs.

Under certain circumstances, when a guest initiates such deferred action,
the hypervisor may miss the request. It is also possible that the guest
may mistakenly assume that it has already marked remote VCPU as needing
a flush when in fact that request had already been processed by the
hypervisor. In both cases this will result in an invalid translation
being present in a vCPU, potentially allowing accesses to memory locations
in that guest's address space that should not be accessible.

Note that only intra-guest memory is vulnerable.

The five patches address both of these problems:
1. The first patch makes sure the hypervisor doesn't accidentally clear
a guest's remote flush request
2. The rest of the patches prevent the race between hypervisor
acknowledging a remote flush request and guest issuing a new one.

Conflicts:
	arch/x86/kvm/x86.c [move from kvm_arch_vcpu_free to kvm_arch_vcpu_destroy]
2020-01-30 18:47:59 +01:00
Boris Ostrovsky 917248144d x86/kvm: Cache gfn to pfn translation
__kvm_map_gfn()'s call to gfn_to_pfn_memslot() is
* relatively expensive
* in certain cases (such as when done from atomic context) cannot be called

Stashing gfn-to-pfn mapping should help with both cases.

This is part of CVE-2019-3016.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-30 18:45:55 +01:00
Boris Ostrovsky 1eff70a9ab x86/kvm: Introduce kvm_(un)map_gfn()
kvm_vcpu_(un)map operates on gfns from any current address space.
In certain cases we want to make sure we are not mapping SMRAM
and for that we can use kvm_(un)map_gfn() that we are introducing
in this patch.

This is part of CVE-2019-3016.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-30 18:45:54 +01:00
Sean Christopherson 42cde48b2d KVM: Play nice with read-only memslots when querying host page size
Avoid the "writable" check in __gfn_to_hva_many(), which will always fail
on read-only memslots due to gfn_to_hva() assuming writes.  Functionally,
this allows x86 to create large mappings for read-only memslots that
are backed by HugeTLB mappings.

Note, the changelog for commit 05da45583d ("KVM: MMU: large page
support") states "If the largepage contains write-protected pages, a
large pte is not used.", but "write-protected" refers to pages that are
temporarily read-only, e.g. read-only memslots didn't even exist at the
time.

Fixes: 4d8b81abc4 ("KVM: introduce readonly memslot")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Redone using kvm_vcpu_gfn_to_memslot_prot. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 20:00:02 +01:00
Sean Christopherson f9b84e1922 KVM: Use vcpu-specific gva->hva translation when querying host page size
Use kvm_vcpu_gfn_to_hva() when retrieving the host page size so that the
correct set of memslots is used when handling x86 page faults in SMM.

Fixes: 54bf36aac5 ("KVM: x86: use vcpu-specific functions to read/write/translate GFNs")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 20:00:02 +01:00
Sean Christopherson 005ba37cb8 mm: thp: KVM: Explicitly check for THP when populating secondary MMU
Add a helper, is_transparent_hugepage(), to explicitly check whether a
compound page is a THP and use it when populating KVM's secondary MMU.
The explicit check fixes a bug where a remapped compound page, e.g. for
an XDP Rx socket, is mapped into a KVM guest and is mistaken for a THP,
which results in KVM incorrectly creating a huge page in its secondary
MMU.

Fixes: 936a5fe6e6 ("thp: kvm mmu transparent hugepage support")
Reported-by: syzbot+c9d1fb51ac9d0d10c39d@syzkaller.appspotmail.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 20:00:01 +01:00
Sean Christopherson dc9ce71e66 KVM: Return immediately if __kvm_gfn_to_hva_cache_init() fails
Check the result of __kvm_gfn_to_hva_cache_init() and return immediately
instead of relying on the kvm_is_error_hva() check to detect errors so
that it's abundantly clear KVM intends to immediately bail on an error.

Note, the hva check is still mandatory to handle errors on subqeuesnt
calls with the same generation.  Similarly, always return -EFAULT on
error so that multiple (bad) calls for a given generation will get the
same result, e.g. on an illegal gfn wrap, propagating the return from
__kvm_gfn_to_hva_cache_init() would cause the initial call to return
-EINVAL and subsequent calls to return -EFAULT.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 20:00:00 +01:00
Sean Christopherson 6ad1e29fe0 KVM: Clean up __kvm_gfn_to_hva_cache_init() and its callers
Barret reported a (technically benign) bug where nr_pages_avail can be
accessed without being initialized if gfn_to_hva_many() fails.

  virt/kvm/kvm_main.c:2193:13: warning: 'nr_pages_avail' may be
  used uninitialized in this function [-Wmaybe-uninitialized]

Rather than simply squashing the warning by initializing nr_pages_avail,
fix the underlying issues by reworking __kvm_gfn_to_hva_cache_init() to
return immediately instead of continuing on.  Now that all callers check
the result and/or bail immediately on a bad hva, there's no need to
explicitly nullify the memslot on error.

Reported-by: Barret Rhoden <brho@google.com>
Fixes: f1b9dd5eb8 ("kvm: Disallow wraparound in kvm_gfn_to_hva_cache_init")
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:59 +01:00
Sean Christopherson fcfbc61754 KVM: Check for a bad hva before dropping into the ghc slow path
When reading/writing using the guest/host cache, check for a bad hva
before checking for a NULL memslot, which triggers the slow path for
handing cross-page accesses.  Because the memslot is nullified on error
by __kvm_gfn_to_hva_cache_init(), if the bad hva is encountered after
crossing into a new page, then the kvm_{read,write}_guest() slow path
could potentially write/access the first chunk prior to detecting the
bad hva.

Arguably, performing a partial access is semantically correct from an
architectural perspective, but that behavior is certainly not intended.
In the original implementation, memslot was not explicitly nullified
and therefore the partial access behavior varied based on whether the
memslot itself was null, or if the hva was simply bad.  The current
behavior was introduced as a seemingly unintentional side effect in
commit f1b9dd5eb8 ("kvm: Disallow wraparound in
kvm_gfn_to_hva_cache_init"), which justified the change with "since some
callers don't check the return code from this function, it sit seems
prudent to clear ghc->memslot in the event of an error".

Regardless of intent, the partial access is dependent on _not_ checking
the result of the cache initialization, which is arguably a bug in its
own right, at best simply weird.

Fixes: 8f964525a1 ("KVM: Allow cross page reads and writes from cached translations.")
Cc: Jim Mattson <jmattson@google.com>
Cc: Andrew Honig <ahonig@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:58 +01:00
Paolo Bonzini 7495e22bb1 KVM: Move running VCPU from ARM to common code
For ring-based dirty log tracking, it will be more efficient to account
writes during schedule-out or schedule-in to the currently running VCPU.
We would like to do it even if the write doesn't use the current VCPU's
address space, as is the case for cached writes (see commit 4e335d9e7d,
"Revert "KVM: Support vCPU-based gfn->hva cache"", 2017-05-02).

Therefore, add a mechanism to track the currently-loaded kvm_vcpu struct.
There is already something similar in KVM/ARM; one important difference
is that kvm_arch_vcpu_{load,put} have two callers in virt/kvm/kvm_main.c:
we have to update both the architecture-independent vcpu_{load,put} and
the preempt notifiers.

Another change made in the process is to allow using kvm_get_running_vcpu()
in preemptible code.  This is allowed because preempt notifiers ensure
that the value does not change even after the VCPU thread is migrated.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:54 +01:00
Peter Xu fcd97ad58f KVM: Add build-time error check on kvm_run size
It's already going to reach 2400 Bytes (which is over half of page
size on 4K page archs), so maybe it's good to have this build-time
check in case it overflows when adding new fields.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:52 +01:00
Peter Xu ef82eddc0e KVM: Remove kvm_read_guest_atomic()
Remove kvm_read_guest_atomic() because it's not used anywhere.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:51 +01:00
Sean Christopherson 8bd826d629 KVM: Move vcpu->run page allocation out of kvm_vcpu_init()
Open code the allocation and freeing of the vcpu->run page in
kvm_vm_ioctl_create_vcpu() and kvm_vcpu_destroy() respectively.  Doing
so allows kvm_vcpu_init() to be a pure init function and eliminates
kvm_vcpu_uninit() entirely.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:34 +01:00
Sean Christopherson 9941d224fb KVM: Move putting of vcpu->pid to kvm_vcpu_destroy()
Move the putting of vcpu->pid to kvm_vcpu_destroy().  vcpu->pid is
guaranteed to be NULL when kvm_vcpu_uninit() is called in the error path
of kvm_vm_ioctl_create_vcpu(), e.g. it is explicitly nullified by
kvm_vcpu_init() and is only changed by KVM_RUN.

No functional change intended.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:33 +01:00
Sean Christopherson ddd259c9aa KVM: Drop kvm_arch_vcpu_init() and kvm_arch_vcpu_uninit()
Remove kvm_arch_vcpu_init() and kvm_arch_vcpu_uninit() now that all
arch specific implementations are nops.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:33 +01:00
Sean Christopherson afede96df5 KVM: Drop kvm_arch_vcpu_setup()
Remove kvm_arch_vcpu_setup() now that all arch specific implementations
are nops.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:28 +01:00
Sean Christopherson d5c48debcc KVM: Move initialization of preempt notifier to kvm_vcpu_init()
Initialize the preempt notifier immediately in kvm_vcpu_init() to pave
the way for removing kvm_arch_vcpu_setup(), i.e. to allow arch specific
code to call vcpu_load() during kvm_arch_vcpu_create().

Back when preemption support was added, the location of the call to init
the preempt notifier was perfectly sane.  The overall vCPU creation flow
featured a single arch specific hook and the preempt notifer was used
immediately after its initialization (by vcpu_load()).  E.g.:

        vcpu = kvm_arch_ops->vcpu_create(kvm, n);
        if (IS_ERR(vcpu))
                return PTR_ERR(vcpu);

        preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);

        vcpu_load(vcpu);
        r = kvm_mmu_setup(vcpu);
        vcpu_put(vcpu);
        if (r < 0)
                goto free_vcpu;

Today, the call to preempt_notifier_init() is sandwiched between two
arch specific calls, kvm_arch_vcpu_create() and kvm_arch_vcpu_setup(),
which needlessly forces x86 (and possibly others?) to split its vCPU
creation flow.  Init the preempt notifier prior to any arch specific
call so that each arch can independently decide how best to organize
its creation flow.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:25 +01:00
Sean Christopherson aaba298c6b KVM: Unexport kvm_vcpu_cache and kvm_vcpu_{un}init()
Unexport kvm_vcpu_cache and kvm_vcpu_{un}init() and make them static
now that they are referenced only in kvm_main.c.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:24 +01:00
Sean Christopherson e529ef66e6 KVM: Move vcpu alloc and init invocation to common code
Now that all architectures tightly couple vcpu allocation/free with the
mandatory calls to kvm_{un}init_vcpu(), move the sequences verbatim to
common KVM code.

Move both allocation and initialization in a single patch to eliminate
thrash in arch specific code.  The bisection benefits of moving the two
pieces in separate patches is marginal at best, whereas the odds of
introducing a transient arch specific bug are non-zero.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-27 19:59:20 +01:00
Sean Christopherson 4543bdc088 KVM: Introduce kvm_vcpu_destroy()
Add kvm_vcpu_destroy() and wire up all architectures to call the common
function instead of their arch specific implementation.  The common
destruction function will be used by future patches to move allocation
and initialization of vCPUs to common KVM code, i.e. to free resources
that are allocated by arch agnostic code.

No functional change intended.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-24 09:19:11 +01:00
Sean Christopherson 897cc38eaa KVM: Add kvm_arch_vcpu_precreate() to handle pre-allocation issues
Add a pre-allocation arch hook to handle checks that are currently done
by arch specific code prior to allocating the vCPU object.  This paves
the way for moving the allocation to common KVM code.

Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-24 09:19:07 +01:00
Milan Pandurov 09cbcef6c6 kvm: Refactor handling of VM debugfs files
We can store reference to kvm_stats_debugfs_item instead of copying
its values to kvm_stat_data.
This allows us to remove duplicated code and usage of temporary
kvm_stat_data inside vm_stat_get et al.

Signed-off-by: Milan Pandurov <milanpa@amazon.de>
Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-21 14:45:33 +01:00
Miaohe Lin 311497e0c5 KVM: Fix some writing mistakes
Fix some writing mistakes in the comments.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-21 13:57:44 +01:00
Miaohe Lin 00116795aa KVM: Fix some grammar mistakes
Fix some grammar mistakes in the comments.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-21 13:57:37 +01:00
Miaohe Lin 668effb63d KVM: Fix some wrong function names in comment
Fix some wrong function names in comment. mmu_check_roots is a typo for
mmu_check_root, vmcs_read_any should be vmcs12_read_any and so on.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-21 13:57:23 +01:00
Miaohe Lin d29c03a587 KVM: get rid of var page in kvm_set_pfn_dirty()
We can get rid of unnecessary var page in
kvm_set_pfn_dirty() , thus make code style
similar with kvm_set_pfn_accessed().
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-01-08 17:33:13 +01:00
Miaohe Lin faf0be2216 KVM: Fix jump label out_free_* in kvm_init()
The jump label out_free_1 and out_free_2 deal with
the same stuff, so git rid of one and rename the
label out_free_0a to retain the label name order.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-23 11:29:17 +01:00
Paolo Bonzini 46f4f0aabc Merge branch 'kvm-tsx-ctrl' into HEAD
Conflicts:
	arch/x86/kvm/vmx/vmx.c
2019-11-21 12:03:40 +01:00
Paolo Bonzini 14edff8831 KVM/arm updates for Linux 5.5:
- Allow non-ISV data aborts to be reported to userspace
 - Allow injection of data aborts from userspace
 - Expose stolen time to guests
 - GICv4 performance improvements
 - vgic ITS emulation fixes
 - Simplify FWB handling
 - Enable halt pool counters
 - Make the emulated timer PREEMPT_RT compliant
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Merge tag 'kvmarm-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm updates for Linux 5.5:

- Allow non-ISV data aborts to be reported to userspace
- Allow injection of data aborts from userspace
- Expose stolen time to guests
- GICv4 performance improvements
- vgic ITS emulation fixes
- Simplify FWB handling
- Enable halt pool counters
- Make the emulated timer PREEMPT_RT compliant

Conflicts:
	include/uapi/linux/kvm.h
2019-11-21 09:58:35 +01:00
Radim Krčmář 8750e72a79 KVM: remember position in kvm->vcpus array
Fetching an index for any vcpu in kvm->vcpus array by traversing
the entire array everytime is costly.
This patch remembers the position of each vcpu in kvm->vcpus array
by storing it in vcpus_idx under kvm_vcpu structure.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:21 +01:00
Marc Zyngier 9cb09e7c1c KVM: Add a comment describing the /dev/kvm no_compat handling
Add a comment explaining the rational behind having both
no_compat open and ioctl callbacks to fend off compat tasks.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 10:14:04 +01:00
Marc Zyngier b9876e6de1 KVM: Forbid /dev/kvm being opened by a compat task when CONFIG_KVM_COMPAT=n
On a system without KVM_COMPAT, we prevent IOCTLs from being issued
by a compat task. Although this prevents most silly things from
happening, it can still confuse a 32bit userspace that is able
to open the kvm device (the qemu test suite seems to be pretty
mad with this behaviour).

Take a more radical approach and return a -ENODEV to the compat
task.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-13 17:13:12 +01:00
Linus Torvalds 8c5bd25bf4 Bugfixes: unwinding of KVM_CREATE_VM failure,
VT-d posted interrupts, DAX/ZONE_DEVICE,
 module unload/reload.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Fix unwinding of KVM_CREATE_VM failure, VT-d posted interrupts,
  DAX/ZONE_DEVICE, and module unload/reload"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: MMU: Do not treat ZONE_DEVICE pages as being reserved
  KVM: VMX: Introduce pi_is_pir_empty() helper
  KVM: VMX: Do not change PID.NDST when loading a blocked vCPU
  KVM: VMX: Consider PID.PIR to determine if vCPU has pending interrupts
  KVM: VMX: Fix comment to specify PID.ON instead of PIR.ON
  KVM: X86: Fix initialization of MSR lists
  KVM: fix placement of refcount initialization
  KVM: Fix NULL-ptr deref after kvm_create_vm fails
2019-11-12 13:19:15 -08:00
Sean Christopherson a78986aae9 KVM: MMU: Do not treat ZONE_DEVICE pages as being reserved
Explicitly exempt ZONE_DEVICE pages from kvm_is_reserved_pfn() and
instead manually handle ZONE_DEVICE on a case-by-case basis.  For things
like page refcounts, KVM needs to treat ZONE_DEVICE pages like normal
pages, e.g. put pages grabbed via gup().  But for flows such as setting
A/D bits or shifting refcounts for transparent huge pages, KVM needs to
to avoid processing ZONE_DEVICE pages as the flows in question lack the
underlying machinery for proper handling of ZONE_DEVICE pages.

This fixes a hang reported by Adam Borowski[*] in dev_pagemap_cleanup()
when running a KVM guest backed with /dev/dax memory, as KVM straight up
doesn't put any references to ZONE_DEVICE pages acquired by gup().

Note, Dan Williams proposed an alternative solution of doing put_page()
on ZONE_DEVICE pages immediately after gup() in order to simplify the
auditing needed to ensure is_zone_device_page() is called if and only if
the backing device is pinned (via gup()).  But that approach would break
kvm_vcpu_{un}map() as KVM requires the page to be pinned from map() 'til
unmap() when accessing guest memory, unlike KVM's secondary MMU, which
coordinates with mmu_notifier invalidations to avoid creating stale
page references, i.e. doesn't rely on pages being pinned.

[*] http://lkml.kernel.org/r/20190919115547.GA17963@angband.pl

Reported-by: Adam Borowski <kilobyte@angband.pl>
Analyzed-by: David Hildenbrand <david@redhat.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org
Fixes: 3565fce3a6 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-12 10:17:42 +01:00
Paolo Bonzini e2d3fcaf93 KVM: fix placement of refcount initialization
Reported by syzkaller:

   =============================
   WARNING: suspicious RCU usage
   -----------------------------
   ./include/linux/kvm_host.h:536 suspicious rcu_dereference_check() usage!

   other info that might help us debug this:

   rcu_scheduler_active = 2, debug_locks = 1
   no locks held by repro_11/12688.

   stack backtrace:
   Call Trace:
    dump_stack+0x7d/0xc5
    lockdep_rcu_suspicious+0x123/0x170
    kvm_dev_ioctl+0x9a9/0x1260 [kvm]
    do_vfs_ioctl+0x1a1/0xfb0
    ksys_ioctl+0x6d/0x80
    __x64_sys_ioctl+0x73/0xb0
    do_syscall_64+0x108/0xaa0
    entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit a97b0e773e (kvm: call kvm_arch_destroy_vm if vm creation fails)
sets users_count to 1 before kvm_arch_init_vm(), however, if kvm_arch_init_vm()
fails, we need to decrease this count.  By moving it earlier, we can push
the decrease to out_err_no_arch_destroy_vm without introducing yet another
error label.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=15209b84e00000

Reported-by: syzbot+75475908cd0910f141ee@syzkaller.appspotmail.com
Fixes: a97b0e773e ("kvm: call kvm_arch_destroy_vm if vm creation fails")
Cc: Jim Mattson <jmattson@google.com>
Analyzed-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-11 15:48:03 +01:00
Paolo Bonzini 8a44119a98 KVM: Fix NULL-ptr deref after kvm_create_vm fails
Reported by syzkaller:

    kasan: CONFIG_KASAN_INLINE enabled
    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN
    CPU: 0 PID: 14727 Comm: syz-executor.3 Not tainted 5.4.0-rc4+ #0
    RIP: 0010:kvm_coalesced_mmio_init+0x5d/0x110 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:121
    Call Trace:
     kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3446 [inline]
     kvm_dev_ioctl+0x781/0x1490 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3494
     vfs_ioctl fs/ioctl.c:46 [inline]
     file_ioctl fs/ioctl.c:509 [inline]
     do_vfs_ioctl+0x196/0x1150 fs/ioctl.c:696
     ksys_ioctl+0x62/0x90 fs/ioctl.c:713
     __do_sys_ioctl fs/ioctl.c:720 [inline]
     __se_sys_ioctl fs/ioctl.c:718 [inline]
     __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:718
     do_syscall_64+0xca/0x5d0 arch/x86/entry/common.c:290
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit 9121923c45 ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
moves memslots and buses allocations around, however, if kvm->srcu/irq_srcu fails
initialization, NULL will be returned instead of error code, NULL will not be intercepted
in kvm_dev_ioctl_create_vm() and be dereferenced by kvm_coalesced_mmio_init(), this patch
fixes it.

Moving the initialization is required anyway to avoid an incorrect synchronize_srcu that
was also reported by syzkaller:

 wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136
 __synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:921
 synchronize_srcu_expedited kernel/rcu/srcutree.c:946 [inline]
 synchronize_srcu+0x239/0x3e8 kernel/rcu/srcutree.c:997
 kvm_page_track_unregister_notifier+0xe7/0x130 arch/x86/kvm/page_track.c:212
 kvm_mmu_uninit_vm+0x1e/0x30 arch/x86/kvm/mmu.c:5828
 kvm_arch_destroy_vm+0x4a2/0x5f0 arch/x86/kvm/x86.c:9579
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:702 [inline]

so do it.

Reported-by: syzbot+89a8060879fa0bd2db4f@syzkaller.appspotmail.com
Reported-by: syzbot+e27e7027eb2b80e44225@syzkaller.appspotmail.com
Fixes: 9121923c45 ("kvm: Allocate memslots and buses before calling kvm_arch_init_vm")
Cc: Jim Mattson <jmattson@google.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-11 15:48:02 +01:00
Junaid Shahid 1aa9b9572b kvm: x86: mmu: Recovery of shattered NX large pages
The page table pages corresponding to broken down large pages are zapped in
FIFO order, so that the large page can potentially be recovered, if it is
not longer being used for execution.  This removes the performance penalty
for walking deeper EPT page tables.

By default, one large page will last about one hour once the guest
reaches a steady state.

Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-11-04 20:26:00 +01:00
Junaid Shahid c57c80467f kvm: Add helper function for creating VM worker threads
Add a function to create a kernel thread associated with a given VM. In
particular, it ensures that the worker thread inherits the priority and
cgroups of the calling thread.

Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-11-04 12:22:02 +01:00
Jim Mattson a97b0e773e kvm: call kvm_arch_destroy_vm if vm creation fails
In kvm_create_vm(), if we've successfully called kvm_arch_init_vm(), but
then fail later in the function, we need to call kvm_arch_destroy_vm()
so that it can do any necessary cleanup (like freeing memory).

Fixes: 44a95dae1d ("KVM: x86: Detect and Initialize AVIC support")

Signed-off-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Junaid Shahid <junaids@google.com>
[Remove dependency on "kvm: Don't clear reference count on
 kvm_create_vm() error path" which was not committed. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-31 12:13:16 +01:00
Jim Mattson 9121923c45 kvm: Allocate memslots and buses before calling kvm_arch_init_vm
This reorganization will allow us to call kvm_arch_destroy_vm in the
event that kvm_create_vm fails after calling kvm_arch_init_vm.

Suggested-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-25 13:32:33 +02:00
Sean Christopherson 149487bdac KVM: Add separate helper for putting borrowed reference to kvm
Add a new helper, kvm_put_kvm_no_destroy(), to handle putting a borrowed
reference[*] to the VM when installing a new file descriptor fails.  KVM
expects the refcount to remain valid in this case, as the in-progress
ioctl() has an explicit reference to the VM.  The primary motiviation
for the helper is to document that the 'kvm' pointer is still valid
after putting the borrowed reference, e.g. to document that doing
mutex(&kvm->lock) immediately after putting a ref to kvm isn't broken.

[*] When exposing a new object to userspace via a file descriptor, e.g.
    a new vcpu, KVM grabs a reference to itself (the VM) prior to making
    the object visible to userspace to avoid prematurely freeing the VM
    in the scenario where userspace immediately closes file descriptor.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-22 15:48:30 +02:00
Wanpeng Li 44551b2f69 KVM: Don't shrink/grow vCPU halt_poll_ns if host side polling is disabled
Don't waste cycles to shrink/grow vCPU halt_poll_ns if host
side polling is disabled.

Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-10-22 13:31:14 +02:00
Steven Price 8538cb22bb KVM: Allow kvm_device_ops to be const
Currently a kvm_device_ops structure cannot be const without triggering
compiler warnings. However the structure doesn't need to be written to
and, by marking it const, it can be read-only in memory. Add some more
const keywords to allow this.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-10-21 19:20:28 +01:00
Paolo Bonzini 833b45de69 kvm: x86, powerpc: do not allow clearing largepages debugfs entry
The largepages debugfs entry is incremented/decremented as shadow
pages are created or destroyed.  Clearing it will result in an
underflow, which is harmless to KVM but ugly (and could be
misinterpreted by tools that use debugfs information), so make
this particular statistic read-only.

Cc: kvm-ppc@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-09-30 18:52:00 +02:00
Marc Zyngier 07ab0f8d9a KVM: Call kvm_arch_vcpu_blocking early into the blocking sequence
When a vpcu is about to block by calling kvm_vcpu_block, we call
back into the arch code to allow any form of synchronization that
may be required at this point (SVN stops the AVIC, ARM synchronises
the VMCR and enables GICv4 doorbells). But this synchronization
comes in quite late, as we've potentially waited for halt_poll_ns
to expire.

Instead, let's move kvm_arch_vcpu_blocking() to the beginning of
kvm_vcpu_block(), which on ARM has several benefits:

- VMCR gets synchronised early, meaning that any interrupt delivered
  during the polling window will be evaluated with the correct guest
  PMR
- GICv4 doorbells are enabled, which means that any guest interrupt
  directly injected during that window will be immediately recognised

Tang Nianyao ran some tests on a GICv4 machine to evaluate such
change, and reported up to a 10% improvement for netperf:

<quote>
	netperf result:
	D06 as server, intel 8180 server as client
	with change:
	package 512 bytes - 5500 Mbits/s
	package 64 bytes - 760 Mbits/s
	without change:
	package 512 bytes - 5000 Mbits/s
	package 64 bytes - 710 Mbits/s
</quote>

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
2019-08-18 18:50:44 +01:00
Paolo Bonzini 8f946da73a kvm: remove unnecessary PageReserved check
The same check is already done in kvm_is_reserved_pfn.

Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-09 16:49:58 +02:00
Greg KH 3e7093d045 KVM: no need to check return value of debugfs_create functions
When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Also, when doing this, change kvm_arch_create_vcpu_debugfs() to return
void instead of an integer, as we should not care at all about if this
function actually does anything or not.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Cc: <kvm@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05 12:55:49 +02:00
Paolo Bonzini 741cbbae07 KVM: remove kvm_arch_has_vcpu_debugfs()
There is no need for this function as all arches have to implement
kvm_arch_create_vcpu_debugfs() no matter what.  A #define symbol
let us actually simplify the code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05 12:55:48 +02:00
Wanpeng Li 17e433b543 KVM: Fix leak vCPU's VMCS value into other pCPU
After commit d73eb57b80 (KVM: Boost vCPUs that are delivering interrupts), a
five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs
on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting
in the VMs after stress testing:

 INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073)
 Call Trace:
   flush_tlb_mm_range+0x68/0x140
   tlb_flush_mmu.part.75+0x37/0xe0
   tlb_finish_mmu+0x55/0x60
   zap_page_range+0x142/0x190
   SyS_madvise+0x3cd/0x9c0
   system_call_fastpath+0x1c/0x21

swait_active() sustains to be true before finish_swait() is called in
kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account
by kvm_vcpu_on_spin() loop greatly increases the probability condition
kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv
is enabled the yield-candidate vCPU's VMCS RVI field leaks(by
vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current
VMCS.

This patch fixes it by checking conservatively a subset of events.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: stable@vger.kernel.org
Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05 12:55:47 +02:00
Wanpeng Li 046ddeed04 KVM: Check preempted_in_kernel for involuntary preemption
preempted_in_kernel is updated in preempt_notifier when involuntary preemption
ocurrs, it can be stale when the voluntarily preempted vCPUs are taken into
account by kvm_vcpu_on_spin() loop. This patch lets it just check preempted_in_kernel
for involuntary preemption.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-08-05 12:55:46 +02:00
Wanpeng Li d73eb57b80 KVM: Boost vCPUs that are delivering interrupts
Inspired by commit 9cac38dd5d (KVM/s390: Set preempted flag during
vcpu wakeup and interrupt delivery), we want to also boost not just
lock holders but also vCPUs that are delivering interrupts. Most
smp_call_function_many calls are synchronous, so the IPI target vCPUs
are also good yield candidates.  This patch introduces vcpu->ready to
boost vCPUs during wakeup and interrupt delivery time; unlike s390 we do
not reuse vcpu->preempted so that voluntarily preempted vCPUs are taken
into account by kvm_vcpu_on_spin, but vmx_vcpu_pi_put is not affected
(VT-d PI handles voluntary preemption separately, in pi_pre_block).

Testing on 80 HT 2 socket Xeon Skylake server, with 80 vCPUs VM 80GB RAM:
ebizzy -M

            vanilla     boosting    improved
1VM          21443       23520         9%
2VM           2800        8000       180%
3VM           1800        3100        72%

Testing on my Haswell desktop 8 HT, with 8 vCPUs VM 8GB RAM, two VMs,
one running ebizzy -M, the other running 'stress --cpu 2':

w/ boosting + w/o pv sched yield(vanilla)

            vanilla     boosting   improved
              1570         4000      155%

w/ boosting + w/ pv sched yield(vanilla)

            vanilla     boosting   improved
              1844         5157      179%

w/o boosting, perf top in VM:

 72.33%  [kernel]       [k] smp_call_function_many
  4.22%  [kernel]       [k] call_function_i
  3.71%  [kernel]       [k] async_page_fault

w/ boosting, perf top in VM:

 38.43%  [kernel]       [k] smp_call_function_many
  6.31%  [kernel]       [k] async_page_fault
  6.13%  libc-2.23.so   [.] __memcpy_avx_unaligned
  4.88%  [kernel]       [k] call_function_interrupt

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-07-20 09:00:45 +02:00
Paolo Bonzini a45ff5994c KVM/arm updates for 5.3
- Add support for chained PMU counters in guests
 - Improve SError handling
 - Handle Neoverse N1 erratum #1349291
 - Allow side-channel mitigation status to be migrated
 - Standardise most AArch64 system register accesses to msr_s/mrs_s
 - Fix host MPIDR corruption on 32bit
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Merge tag 'kvm-arm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm updates for 5.3

- Add support for chained PMU counters in guests
- Improve SError handling
- Handle Neoverse N1 erratum #1349291
- Allow side-channel mitigation status to be migrated
- Standardise most AArch64 system register accesses to msr_s/mrs_s
- Fix host MPIDR corruption on 32bit
2019-07-11 15:14:16 +02:00
KarimAllah Ahmed b614c60278 KVM: Properly check if "page" is valid in kvm_vcpu_unmap
The field "page" is initialized to KVM_UNMAPPED_PAGE when it is not used
(i.e. when the memory lives outside kernel control). So this check will
always end up using kunmap even for memremap regions.

Fixes: e45adf665a ("KVM: Introduce a new guest mapping API")
Cc: stable@vger.kernel.org
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-07-10 16:25:39 +02:00
Thomas Gleixner 20c8ccb197 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499
Based on 1 normalized pattern(s):

  this work is licensed under the terms of the gnu gpl version 2 see
  the copying file in the top level directory

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 35 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:53 +02:00
Junaid Shahid 0d9ce162cf kvm: Convert kvm_lock to a mutex
It doesn't seem as if there is any particular need for kvm_lock to be a
spinlock, so convert the lock to a mutex so that sleepable functions (in
particular cond_resched()) can be called while holding it.

Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-06-05 14:14:50 +02:00
Sean Christopherson f257d6dcda KVM: Directly return result from kvm_arch_check_processor_compat()
Add a wrapper to invoke kvm_arch_check_processor_compat() so that the
boilerplate ugliness of checking virtualization support on all CPUs is
hidden from the arch specific code.  x86's implementation in particular
is quite heinous, as it unnecessarily propagates the out-param pattern
into kvm_x86_ops.

While the x86 specific issue could be resolved solely by changing
kvm_x86_ops, make the change for all architectures as returning a value
directly is prettier and technically more robust, e.g. s390 doesn't set
the out param, which could lead to subtle breakage in the (highly
unlikely) scenario where the out-param was not pre-initialized by the
caller.

Opportunistically annotate svm_check_processor_compat() with __init.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-06-04 19:27:32 +02:00
Thomas Huth a86cb413f4 KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID
KVM_CAP_MAX_VCPU_ID is currently always reporting KVM_MAX_VCPU_ID on all
architectures. However, on s390x, the amount of usable CPUs is determined
during runtime - it is depending on the features of the machine the code
is running on. Since we are using the vcpu_id as an index into the SCA
structures that are defined by the hardware (see e.g. the sca_add_vcpu()
function), it is not only the amount of CPUs that is limited by the hard-
ware, but also the range of IDs that we can use.
Thus KVM_CAP_MAX_VCPU_ID must be determined during runtime on s390x, too.
So the handling of KVM_CAP_MAX_VCPU_ID has to be moved from the common
code into the architecture specific code, and on s390x we have to return
the same value here as for KVM_CAP_MAX_VCPUS.
This problem has been discovered with the kvm_create_max_vcpus selftest.
With this change applied, the selftest now passes on s390x, too.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20190523164309.13345-9-thuth@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2019-05-28 15:52:19 +02:00
Christian Borntraeger eb1f2f387d kvm: fix compile on s390 part 2
We also need to fence the memunmap part.

Fixes: e45adf665a ("KVM: Introduce a new guest mapping API")
Fixes: d30b214d1d (kvm: fix compilation on s390)
Cc: Michal Kubecek <mkubecek@suse.cz>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2019-05-28 15:51:52 +02:00
Paolo Bonzini d30b214d1d kvm: fix compilation on s390
s390 does not have memremap, even though in this particular case it
would be useful.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-24 21:27:07 +02:00
Wanpeng Li 2eb06c306a KVM: Fix spinlock taken warning during host resume
WARNING: CPU: 0 PID: 13554 at kvm/arch/x86/kvm//../../../virt/kvm/kvm_main.c:4183 kvm_resume+0x3c/0x40 [kvm]
  CPU: 0 PID: 13554 Comm: step_after_susp Tainted: G           OE     5.1.0-rc4+ #1
  RIP: 0010:kvm_resume+0x3c/0x40 [kvm]
  Call Trace:
   syscore_resume+0x63/0x2d0
   suspend_devices_and_enter+0x9d1/0xa40
   pm_suspend+0x33a/0x3b0
   state_store+0x82/0xf0
   kobj_attr_store+0x12/0x20
   sysfs_kf_write+0x4b/0x60
   kernfs_fop_write+0x120/0x1a0
   __vfs_write+0x1b/0x40
   vfs_write+0xcd/0x1d0
   ksys_write+0x5f/0xe0
   __x64_sys_write+0x1a/0x20
   do_syscall_64+0x6f/0x6c0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Commit ca84d1a24 (KVM: x86: Add clock sync request to hardware enable) mentioned
that "we always hold kvm_lock when hardware_enable is called.  The one place that
doesn't need to worry about it is resume, as resuming a frozen CPU, the spinlock
won't be taken." However, commit 6706dae9 (virt/kvm: Replace spin_is_locked() with
lockdep) introduces a bug, it asserts when the lock is not held which is contrary
to the original goal.

This patch fixes it by WARN_ON when the lock is held.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Fixes: 6706dae9 ("virt/kvm: Replace spin_is_locked() with lockdep")
[Wrap with #ifdef CONFIG_LOCKDEP - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-24 21:27:03 +02:00
Linus Torvalds 0ef0fd3515 * ARM: support for SVE and Pointer Authentication in guests, PMU improvements
* POWER: support for direct access to the POWER9 XIVE interrupt controller,
 memory and performance optimizations.
 
 * x86: support for accessing memory not backed by struct page, fixes and refactoring
 
 * Generic: dirty page tracking improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "ARM:
   - support for SVE and Pointer Authentication in guests
   - PMU improvements

  POWER:
   - support for direct access to the POWER9 XIVE interrupt controller
   - memory and performance optimizations

  x86:
   - support for accessing memory not backed by struct page
   - fixes and refactoring

  Generic:
   - dirty page tracking improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (155 commits)
  kvm: fix compilation on aarch64
  Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
  kvm: x86: Fix L1TF mitigation for shadow MMU
  KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible
  KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
  KVM: PPC: Book3S HV: XIVE: Fix spelling mistake "acessing" -> "accessing"
  KVM: PPC: Book3S HV: Make sure to load LPID for radix VCPUs
  kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete
  tests: kvm: Add tests for KVM_SET_NESTED_STATE
  KVM: nVMX: KVM_SET_NESTED_STATE - Tear down old EVMCS state before setting new state
  tests: kvm: Add tests for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_CPU_ID
  tests: kvm: Add tests to .gitignore
  KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
  KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
  KVM: Fix the bitmap range to copy during clear dirty
  KVM: arm64: Fix ptrauth ID register masking logic
  KVM: x86: use direct accessors for RIP and RSP
  KVM: VMX: Use accessors for GPRs outside of dedicated caching logic
  KVM: x86: Omit caching logic for always-available GPRs
  kvm, x86: Properly check whether a pfn is an MMIO or not
  ...
2019-05-17 10:33:30 -07:00
Paolo Bonzini c011d23ba0 kvm: fix compilation on aarch64
Commit e45adf665a ("KVM: Introduce a new guest mapping API", 2019-01-31)
introduced a build failure on aarch64 defconfig:

$ make -j$(nproc) ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- O=out defconfig \
                Image.gz
...
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
    In function '__kvm_map_gfn':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:9: error:
    implicit declaration of function 'memremap'; did you mean 'memset_p'?
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:46: error:
    'MEMREMAP_WB' undeclared (first use in this function)
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
    In function 'kvm_vcpu_unmap':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1795:3: error:
    implicit declaration of function 'memunmap'; did you mean 'vm_munmap'?

because these functions are declared in <linux/io.h> rather than <asm/io.h>,
and the former was being pulled in already on x86 but not on aarch64.

Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-17 14:08:53 +02:00
Paolo Bonzini 59c5c58c5b Second PPC KVM update for 5.2
- Fix a bug, fix a spelling mistake, remove some useless code.
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Merge tag 'kvm-ppc-next-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD

PPC KVM update for 5.2

* Support for guests to access the new POWER9 XIVE interrupt controller
  hardware directly, reducing interrupt latency and overhead for guests.

* In-kernel implementation of the H_PAGE_INIT hypercall.

* Reduce memory usage of sparsely-populated IOMMU tables.

* Several bug fixes.

Second PPC KVM update for 5.2

* Fix a bug, fix a spelling mistake, remove some useless code.
2019-05-15 23:39:38 +02:00
Jérôme Glisse dfcd66604c mm/mmu_notifier: convert user range->blockable to helper function
Use the mmu_notifier_range_blockable() helper function instead of directly
dereferencing the range->blockable field.  This is done to make it easier
to change the mmu_notifier range field.

This patch is the outcome of the following coccinelle patch:

%<-------------------------------------------------------------------
@@
identifier I1, FN;
@@
FN(..., struct mmu_notifier_range *I1, ...) {
<...
-I1->blockable
+mmu_notifier_range_blockable(I1)
...>
}
------------------------------------------------------------------->%

spatch --in-place --sp-file blockable.spatch --dir .

Link: http://lkml.kernel.org/r/20190326164747.24405-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Cédric Le Goater 4894fbcce8 KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
There is no need to test for the device pointer validity when releasing
a KVM device. The file descriptor should identify it safely.

Fixes: 2bde9b3ec8 ("KVM: Introduce a 'release' method for KVM devices")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-05-14 12:06:03 +10:00
Peter Xu d7547c55cb KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
The previous KVM_CAP_MANUAL_DIRTY_LOG_PROTECT has some problem which
blocks the correct usage from userspace.  Obsolete the old one and
introduce a new capability bit for it.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-08 13:48:24 +02:00
Peter Xu 53eac7a8f8 KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
Just imaging the case where num_pages < BITS_PER_LONG, then the loop
will be skipped while it shouldn't.

Signed-off-by: Peter Xu <peterx@redhat.com>
Fixes: 2a31b9db15
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-08 13:43:28 +02:00
Peter Xu 4ddc920457 KVM: Fix the bitmap range to copy during clear dirty
kvm_dirty_bitmap_bytes() will return the size of the dirty bitmap of
the memslot rather than the size of bitmap passed over from the ioctl.
Here for KVM_CLEAR_DIRTY_LOG we should only copy exactly the size of
bitmap that covers kvm_clear_dirty_log.num_pages.

Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 2a31b9db15
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-05-08 13:42:53 +02:00
KarimAllah Ahmed e45adf665a KVM: Introduce a new guest mapping API
In KVM, specially for nested guests, there is a dominant pattern of:

	=> map guest memory -> do_something -> unmap guest memory

In addition to all this unnecessarily noise in the code due to boiler plate
code, most of the time the mapping function does not properly handle memory
that is not backed by "struct page". This new guest mapping API encapsulate
most of this boiler plate code and also handles guest memory that is not
backed by "struct page".

The current implementation of this API is using memremap for memory that is
not backed by a "struct page" which would lead to a huge slow-down if it
was used for high-frequency mapping operations. The API does not have any
effect on current setups where guest memory is backed by a "struct page".
Further patches are going to also introduce a pfn-cache which would
significantly improve the performance of the memremap case.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-30 21:32:51 +02:00
Jiang Biao b8b002209c kvm_main: fix some comments
is_dirty has been renamed to flush, but the comment for it is
outdated. And the description about @flush parameter for
kvm_clear_dirty_log_protect() is missing, add it in this patch
as well.

Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-30 21:32:19 +02:00
Paolo Bonzini 65c4189de8 KVM: fix KVM_CLEAR_DIRTY_LOG for memory slots of unaligned size
If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.

To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.

Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8ed ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-30 21:32:19 +02:00
Paolo Bonzini da8f0d97b2 KVM: s390: Features and fixes for 5.2
- VSIE crypto fixes
 - new guest features for gen15
 - disable halt polling for nested virtualization with overcommit
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Merge tag 'kvm-s390-next-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Features and fixes for 5.2

- VSIE crypto fixes
- new guest features for gen15
- disable halt polling for nested virtualization with overcommit
2019-04-30 21:29:14 +02:00
Paolo Bonzini 76d58e0f07 KVM: fix KVM_CLEAR_DIRTY_LOG for memory slots of unaligned size
If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.

To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.

Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8ed ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-30 21:22:15 +02:00
Cédric Le Goater 2bde9b3ec8 KVM: Introduce a 'release' method for KVM devices
When a P9 sPAPR VM boots, the CAS negotiation process determines which
interrupt mode to use (XICS legacy or XIVE native) and invokes a
machine reset to activate the chosen mode.

To be able to switch from one interrupt mode to another, we introduce
the capability to release a KVM device without destroying the VM. The
KVM device interface is extended with a new 'release' method which is
called when the file descriptor of the device is closed.

Once 'release' is called, the 'destroy' method will not be called
anymore as the device is removed from the device list of the VM.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-04-30 19:35:16 +10:00
Cédric Le Goater a1cd3f0883 KVM: Introduce a 'mmap' method for KVM devices
Some KVM devices will want to handle special mappings related to the
underlying HW. For instance, the XIVE interrupt controller of the
POWER9 processor has MMIO pages for thread interrupt management and
for interrupt source control that need to be exposed to the guest when
the OS has the required support.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-04-30 19:35:16 +10:00
Christian Borntraeger cdd6ad3ac6 KVM: polling: add architecture backend to disable polling
There are cases where halt polling is unwanted. For example when running
KVM on an over committed LPAR we rather want to give back the CPU to
neighbour LPARs instead of polling. Let us provide a callback that
allows architectures to disable polling.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2019-04-26 09:08:17 +02:00
Paolo Bonzini c110ae578c kvm: move KVM_CAP_NR_MEMSLOTS to common code
All architectures except MIPS were defining it in the same way,
and memory slots are handled entirely by common code so there
is no point in keeping the definition per-architecture.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-16 15:39:08 +02:00
Paolo Bonzini 1d487e9bf8 KVM: fix spectrev1 gadgets
These were found with smatch, and then generalized when applicable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-16 15:38:07 +02:00
Sean Christopherson ddba91801a KVM: Reject device ioctls from processes other than the VM's creator
KVM's API requires thats ioctls must be issued from the same process
that created the VM.  In other words, userspace can play games with a
VM's file descriptors, e.g. fork(), SCM_RIGHTS, etc..., but only the
creator can do anything useful.  Explicitly reject device ioctls that
are issued by a process other than the VM's creator, and update KVM's
API documentation to extend its requirements to device ioctls.

Fixes: 852b6d57dc ("kvm: add device control API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-03-28 17:27:06 +01:00
Linus Torvalds 636deed6c0 ARM: some cleanups, direct physical timer assignment, cache sanitization
for 32-bit guests
 
 s390: interrupt cleanup, introduction of the Guest Information Block,
 preparation for processor subfunctions in cpu models
 
 PPC: bug fixes and improvements, especially related to machine checks
 and protection keys
 
 x86: many, many cleanups, including removing a bunch of MMU code for
 unnecessary optimizations; plus AVIC fixes.
 
 Generic: memcg accounting
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "ARM:
   - some cleanups
   - direct physical timer assignment
   - cache sanitization for 32-bit guests

  s390:
   - interrupt cleanup
   - introduction of the Guest Information Block
   - preparation for processor subfunctions in cpu models

  PPC:
   - bug fixes and improvements, especially related to machine checks
     and protection keys

  x86:
   - many, many cleanups, including removing a bunch of MMU code for
     unnecessary optimizations
   - AVIC fixes

  Generic:
   - memcg accounting"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (147 commits)
  kvm: vmx: fix formatting of a comment
  KVM: doc: Document the life cycle of a VM and its resources
  MAINTAINERS: Add KVM selftests to existing KVM entry
  Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()"
  KVM: PPC: Book3S: Add count cache flush parameters to kvmppc_get_cpu_char()
  KVM: PPC: Fix compilation when KVM is not enabled
  KVM: Minor cleanups for kvm_main.c
  KVM: s390: add debug logging for cpu model subfunctions
  KVM: s390: implement subfunction processor calls
  arm64: KVM: Fix architecturally invalid reset value for FPEXC32_EL2
  KVM: arm/arm64: Remove unused timer variable
  KVM: PPC: Book3S: Improve KVM reference counting
  KVM: PPC: Book3S HV: Fix build failure without IOMMU support
  Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"
  x86: kvmguest: use TSC clocksource if invariant TSC is exposed
  KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start
  KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter
  KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns
  KVM: x86/mmu: Consolidate kvm_mmu_zap_all() and kvm_mmu_zap_mmio_sptes()
  KVM: x86/mmu: WARN if zapping a MMIO spte results in zapping children
  ...
2019-03-15 15:00:28 -07:00
Linus Torvalds 3717f613f4 Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
 "The main RCU related changes in this cycle were:

   - Additional cleanups after RCU flavor consolidation

   - Grace-period forward-progress cleanups and improvements

   - Documentation updates

   - Miscellaneous fixes

   - spin_is_locked() conversions to lockdep

   - SPDX changes to RCU source and header files

   - SRCU updates

   - Torture-test updates, including nolibc updates and moving nolibc to
     tools/include"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  locking/locktorture: Convert to SPDX license identifier
  linux/torture: Convert to SPDX license identifier
  torture: Convert to SPDX license identifier
  linux/srcu: Convert to SPDX license identifier
  linux/rcutree: Convert to SPDX license identifier
  linux/rcutiny: Convert to SPDX license identifier
  linux/rcu_sync: Convert to SPDX license identifier
  linux/rcu_segcblist: Convert to SPDX license identifier
  linux/rcupdate: Convert to SPDX license identifier
  linux/rcu_node_tree: Convert to SPDX license identifier
  rcu/update: Convert to SPDX license identifier
  rcu/tree: Convert to SPDX license identifier
  rcu/tiny: Convert to SPDX license identifier
  rcu/sync: Convert to SPDX license identifier
  rcu/srcu: Convert to SPDX license identifier
  rcu/rcutorture: Convert to SPDX license identifier
  rcu/rcu_segcblist: Convert to SPDX license identifier
  rcu/rcuperf: Convert to SPDX license identifier
  rcu/rcu.h: Convert to SPDX license identifier
  RCU/torture.txt: Remove section MODULE PARAMETERS
  ...
2019-03-05 14:49:11 -08:00
Greg Kroah-Hartman 8ed0579c12 kvm: properly check debugfs dentry before using it
debugfs can now report an error code if something went wrong instead of
just NULL.  So if the return value is to be used as a "real" dentry, it
needs to be checked if it is an error before dereferencing it.

This is now happening because of ff9fb72bc0 ("debugfs: return error
values, not NULL").  syzbot has found a way to trigger multiple debugfs
files attempting to be created, which fails, and then the error code
gets passed to dentry_path_raw() which obviously does not like it.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-28 08:57:32 -08:00
Leo Yan a242010776 KVM: Minor cleanups for kvm_main.c
This patch contains two minor cleanups: firstly it puts exported symbol
for kvm_io_bus_write() by following the function definition; secondly it
removes a redundant blank line.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-22 17:43:57 +01:00
Lan Tianyu a67794cafb Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"
The value of "dirty_bitmap[i]" is already check before setting its value
to mask. The following check of "mask" is redundant. The check of "mask" was
introduced by commit 58d2930f4e ("KVM: Eliminate extra function calls in
kvm_get_dirty_log_protect()"), revert it.

Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20 22:48:52 +01:00
Nir Weiner dee339b5c1 KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start
grow_halt_poll_ns() have a strange behaviour in case
(vcpu->halt_poll_ns != 0) &&
(vcpu->halt_poll_ns < halt_poll_ns_grow_start).

In this case, vcpu->halt_poll_ns will be multiplied by grow factor
(halt_poll_ns_grow) which will require several grow iteration in order
to reach a value bigger than halt_poll_ns_grow_start.
This means that growing vcpu->halt_poll_ns from value of 0 is slower
than growing it from a positive value less than halt_poll_ns_grow_start.
Which is misleading and inaccurate.

Fix issue by changing grow_halt_poll_ns() to set vcpu->halt_poll_ns
to halt_poll_ns_grow_start in any case that
(vcpu->halt_poll_ns < halt_poll_ns_grow_start).
Regardless if vcpu->halt_poll_ns is 0.

use READ_ONCE to get a consistent number for all cases.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20 22:48:51 +01:00
Nir Weiner 49113d360b KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter
The hard-coded value 10000 in grow_halt_poll_ns() stands for the initial
start value when raising up vcpu->halt_poll_ns.
It actually sets the first timeout to the first polling session.
This value has significant effect on how tolerant we are to outliers.
On the standard case, higher value is better - we will spend more time
in the polling busyloop, handle events/interrupts faster and result
in better performance.
But on outliers it puts us in a busy loop that does nothing.
Even if the shrink factor is zero, we will still waste time on the first
iteration.
The optimal value changes between different workloads. It depends on
outliers rate and polling sessions length.
As this value has significant effect on the dynamic halt-polling
algorithm, it should be configurable and exposed.

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Nir Weiner <nir.weiner@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20 22:48:50 +01:00