Modifying a non-existent slot is not allowed. Also check that the
first loop doesn't move a deleted slot beyond the used part of
the mslots array.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Before commit 0e60b0799f (kvm: change memslot sorting rule from size
to GFN, 2014-12-01), the memslots' sorting key was npages, meaning
that a valid memslot couldn't have its sorting key equal to zero.
On the other hand, a valid memslot can have base_gfn == 0, and invalid
memslots are identified by base_gfn == npages == 0.
Because of this, commit 0e60b0799f broke the invariant that invalid
memslots are at the end of the mslots array. When a memslot with
base_gfn == 0 was created, any invalid memslot before it were left
in place.
This can be fixed by changing the insertion to use a ">=" comparison
instead of "<=", but some care is needed to avoid breaking the case
of deleting a memslot; see the comment in update_memslots.
Thanks to Tiejun Chen for posting an initial patch for this bug.
Reported-by: Jamie Heilman <jamie@audible.transient.net>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Tested-by: Jamie Heilman <jamie@audible.transient.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
problems, clarifies VCPU init, and fixes a regression concerning the
VGIC init flow.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJUjsVhAAoJEEtpOizt6ddy5rIH/1V/YVwhprC55YqdHelU9Qu2
Muzsx+7F71NxC7xgMGFqPD1YrPR+hxvoPhy+ADOBlvcqlolrkDnV9I+8e3geaYNc
nZ/yEnoGTtbAggiS1smx7usBv34Z88Sd5txNjmj1cmHBy+VOWlyidWMkGBTsfBRe
mVc61BDUfyC47udgRHXhwS80sbHLJHElmADisFOVmQNBYwwiHiTdx0hMBMnHcC3Y
/3T0tKxHdeTISnmA+J+n7TcChtTIM4xqC6kwf3rw3b7XX8gdtTKylDHX2GLAg646
RdebAG2twmGpIc6SxXZbo38f3oY9OFo1Le5xZGa6iUjD56VDw/e4wg4iA2juo0Y=
=J2Ut
-----END PGP SIGNATURE-----
Merge tag 'kvm-arm-for-3.19-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
Second round of changes for KVM for arm/arm64 for v3.19; fixes reboot
problems, clarifies VCPU init, and fixes a regression concerning the
VGIC init flow.
Conflicts:
arch/ia64/kvm/kvm-ia64.c [deleted in HEAD and modified in kvmarm]
We currently track the pid of the task that runs the VCPU in vcpu_load.
If a yield to that VCPU is triggered while the PID of the wrong thread
is active, the wrong thread might receive a yield, but this will most
likely not help the executing thread at all. Instead, if we only track
the pid on the KVM_RUN ioctl, there are two possibilities:
1) the thread that did a non-KVM_RUN ioctl is holding a mutex that
the VCPU thread is waiting for. In this case, the VCPU thread is not
runnable, but we also do not do a wrong yield.
2) the thread that did a non-KVM_RUN ioctl is sleeping, or doing
something that does not block the VCPU thread. In this case, the
VCPU thread can receive the directed yield correctly.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
CC: Rik van Riel <riel@redhat.com>
CC: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
CC: Michael Mueller <mimu@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_enter_guest() has to be called with preemption disabled and will
set PF_VCPU. Current code takes PF_VCPU as a hint that the VCPU thread
is running and therefore needs no yield.
However, the check on PF_VCPU is wrong on s390, where preemption has
to stay enabled in order to correctly process page faults. Thus,
s390 reenables preemption and starts to execute the guest. The thread
might be scheduled out between kvm_enter_guest() and kvm_exit_guest(),
resulting in PF_VCPU being set but not being run. When this happens,
the opportunity for directed yield is missed.
However, this check is done already in kvm_vcpu_on_spin before calling
kvm_vcpu_yield_loop:
if (!ACCESS_ONCE(vcpu->preempted))
continue;
so the check on PF_VCPU is superfluous in general, and this patch
removes it.
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Current linear search doesn't scale well when
large amount of memslots is used and looked up slot
is not in the beginning memslots array.
Taking in account that memslots don't overlap, it's
possible to switch sorting order of memslots array from
'npages' to 'base_gfn' and use binary search for
memslot lookup by GFN.
As result of switching to binary search lookup times
are reduced with large amount of memslots.
Following is a table of search_memslot() cycles
during WS2008R2 guest boot.
boot, boot + ~10 min
mostly same of using it,
slot lookup randomized lookup
max average average
cycles cycles cycles
13 slots : 1450 28 30
13 slots : 1400 30 40
binary search
117 slots : 13000 30 460
117 slots : 2000 35 180
binary search
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
it will allow to use binary search for GFN -> memslot
lookups, reducing lookup cost with large slots amount.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
UP/DOWN shift loops will shift array in needed
direction and stop at place where new slot should
be placed regardless of old slot size.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
if number of pages haven't changed sorting algorithm
will do nothing, so there is no need to do extra check
to avoid entering sorting logic.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This reverts commit 85c8555ff0 ("KVM: check for !is_zero_pfn() in
kvm_is_mmio_pfn()") and renames the function to kvm_is_reserved_pfn.
The problem being addressed by the patch above was that some ARM code
based the memory mapping attributes of a pfn on the return value of
kvm_is_mmio_pfn(), whose name indeed suggests that such pfns should
be mapped as device memory.
However, kvm_is_mmio_pfn() doesn't do quite what it says on the tin,
and the existing non-ARM users were already using it in a way which
suggests that its name should probably have been 'kvm_is_reserved_pfn'
from the beginning, e.g., whether or not to call get_page/put_page on
it etc. This means that returning false for the zero page is a mistake
and the patch above should be reverted.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Now that ia64 is gone, we can hide deprecated device assignment in x86.
Notable changes:
- kvm_vm_ioctl_assigned_device() was moved to x86/kvm_arch_vm_ioctl()
The easy parts were removed from generic kvm code, remaining
- kvm_iommu_(un)map_pages() would require new code to be moved
- struct kvm_assigned_dev_kernel depends on struct kvm_irq_ack_notifier
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
ia64 does not need them anymore. Ack notifiers become x86-specific
too.
Suggested-by: Gleb Natapov <gleb@kernel.org>
Reviewed-by: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The update_memslots invocation is only needed in one case. Make
the code clearer by moving it to __kvm_set_memory_region, and
removing the wrapper around insert_memslot.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The two kmemdup invocations can be unified. I find that the new
placement of the comment makes it easier to see what happens.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This completes the optimization from the previous patch, by
removing the KVM_MEM_SLOTS_NUM-iteration loop from insert_memslot.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
memslots is a sorted array. When a slot is changed, heapsort (lib/sort.c)
would take O(n log n) time to update it; an optimized insertion sort will
only cost O(n) on an array with just one item out of order.
Replace sort() with a custom sort that takes advantage of memslots usage
pattern and the known position of the changed slot.
performance change of 128 memslots insertions with gradually increasing
size (the worst case):
heap sort custom sort
max: 249747 2500 cycles
with custom sort alg taking ~98% less then original
update time.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
commit 72dc67a696 ("KVM: remove the usage of the mmap_sem for the protection of the memory slots.")
changed the lock which will be taken. This should be reflected in the function
commentary.
Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Apart from the usual cleanups, here is the summary of new features:
- s390 moves closer towards host large page support
- PowerPC has improved support for debugging (both inside the guest and
via gdbstub) and support for e6500 processors
- ARM/ARM64 support read-only memory (which is necessary to put firmware
in emulated NOR flash)
- x86 has the usual emulator fixes and nested virtualization improvements
(including improved Windows support on Intel and Jailhouse hypervisor
support on AMD), adaptive PLE which helps overcommitting of huge guests.
Also included are some patches that make KVM more friendly to memory
hot-unplug, and fixes for rare caching bugs.
Two patches have trivial mm/ parts that were acked by Rik and Andrew.
Note: I will soon switch to a subkey for signing purposes. To verify
future signed pull requests from me, please update my key with
"gpg --recv-keys 9B4D86F2". You should see 3 new subkeys---the
one for signing will be a 2048-bit RSA key, 4E6B09D7.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=iEVi
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Fixes and features for 3.18.
Apart from the usual cleanups, here is the summary of new features:
- s390 moves closer towards host large page support
- PowerPC has improved support for debugging (both inside the guest
and via gdbstub) and support for e6500 processors
- ARM/ARM64 support read-only memory (which is necessary to put
firmware in emulated NOR flash)
- x86 has the usual emulator fixes and nested virtualization
improvements (including improved Windows support on Intel and
Jailhouse hypervisor support on AMD), adaptive PLE which helps
overcommitting of huge guests. Also included are some patches that
make KVM more friendly to memory hot-unplug, and fixes for rare
caching bugs.
Two patches have trivial mm/ parts that were acked by Rik and Andrew.
Note: I will soon switch to a subkey for signing purposes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (157 commits)
kvm: do not handle APIC access page if in-kernel irqchip is not in use
KVM: s390: count vcpu wakeups in stat.halt_wakeup
KVM: s390/facilities: allow TOD-CLOCK steering facility bit
KVM: PPC: BOOK3S: HV: CMA: Reserve cma region only in hypervisor mode
arm/arm64: KVM: Report correct FSC for unsupported fault types
arm/arm64: KVM: Fix VTTBR_BADDR_MASK and pgd alloc
kvm: Fix kvm_get_page_retry_io __gup retval check
arm/arm64: KVM: Fix set_clear_sgi_pend_reg offset
kvm: x86: Unpin and remove kvm_arch->apic_access_page
kvm: vmx: Implement set_apic_access_page_addr
kvm: x86: Add request bit to reload APIC access page address
kvm: Add arch specific mmu notifier for page invalidation
kvm: Rename make_all_cpus_request() to kvm_make_all_cpus_request() and make it non-static
kvm: Fix page ageing bugs
kvm/x86/mmu: Pass gfn and level to rmapp callback.
x86: kvm: use alternatives for VMCALL vs. VMMCALL if kernel text is read-only
kvm: x86: use macros to compute bank MSRs
KVM: x86: Remove debug assertion of non-PAE reserved bits
kvm: don't take vcpu mutex for obviously invalid vcpu ioctls
kvm: Faults which trigger IO release the mmap_sem
...
This includes a bunch of changes:
- Support read-only memory slots on arm/arm64
- Various changes to fix Sparse warnings
- Correctly detect write vs. read Stage-2 faults
- Various VGIC cleanups and fixes
- Dynamic VGIC data strcuture sizing
- Fix SGI set_clear_pend offset bug
- Fix VTTBR_BADDR Mask
- Correctly report the FSC on Stage-2 faults
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJUJWAdAAoJEEtpOizt6ddy9cMH+gIoUPnRJLe+PPcOOyxOx6pr
+CnD/zAd0sLvxZLP/LBOzu99H3YrbO5kwI/172/8G1zUNI2hp6YxEEJaBCTHrz6l
RwgLy7a3EMMY51nJo5w2dkFUo8cUX9MsHqMpl2Xb7Dvo2ZHp+nDqRjwRY6yi+t4V
dWSJTRG6X+DIWyysij6jBtfKU6MpU+4NW3Zdk1fapf8QDkn+cBtV5X2QcmERCaIe
A1j9hiGi43KA3XWeeePU3aVaxC2XUhTayP8VsfVxoNG2manaS6lqjmbif5ghs/0h
rw7R3/Aj0MJny2zT016MkvKJKRukuVRD6e1lcYghqnSJhL2FossowZ9fHRADpqU=
=QgU8
-----END PGP SIGNATURE-----
Merge tag 'kvm-arm-for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into kvm-next
Changes for KVM for arm/arm64 for 3.18
This includes a bunch of changes:
- Support read-only memory slots on arm/arm64
- Various changes to fix Sparse warnings
- Correctly detect write vs. read Stage-2 faults
- Various VGIC cleanups and fixes
- Dynamic VGIC data strcuture sizing
- Fix SGI set_clear_pend offset bug
- Fix VTTBR_BADDR Mask
- Correctly report the FSC on Stage-2 faults
Conflicts:
virt/kvm/eventfd.c
[duplicate, different patch where the kvm-arm version broke x86.
The kvm tree instead has the right one]
Confusion around -EBUSY and zero (inside a BUG_ON no less).
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This will be used to let the guest run while the APIC access page is
not pinned. Because subsequent patches will fill in the function
for x86, place the (still empty) x86 implementation in the x86.c file
instead of adding an inline function in kvm_host.h.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Different architectures need different requests, and in fact we
will use this function in architecture-specific code later. This
will be outside kvm_main.c, so make it non-static and rename it to
kvm_make_all_cpus_request().
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1. We were calling clear_flush_young_notify in unmap_one, but we are
within an mmu notifier invalidate range scope. The spte exists no more
(due to range_start) and the accessed bit info has already been
propagated (due to kvm_pfn_set_accessed). Simply call
clear_flush_young.
2. We clear_flush_young on a primary MMU PMD, but this may be mapped
as a collection of PTEs by the secondary MMU (e.g. during log-dirty).
This required expanding the interface of the clear_flush_young mmu
notifier, so a lot of code has been trivially touched.
3. In the absence of shadow_accessed_mask (e.g. EPT A bit), we emulate
the access bit by blowing the spte. This requires proper synchronizing
with MMU notifier consumers, like every other removal of spte's does.
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vcpu ioctls can hang the calling thread if issued while a vcpu is running.
However, invalid ioctls can happen when userspace tries to probe the kind
of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case,
we know the ioctl is going to be rejected as invalid anyway and we can
fail before trying to take the vcpu mutex.
This patch does not change functionality, it just makes invalid ioctls
fail faster.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When KVM handles a tdp fault it uses FOLL_NOWAIT. If the guest memory
has been swapped out or is behind a filemap, this will trigger async
readahead and return immediately. The rationale is that KVM will kick
back the guest with an "async page fault" and allow for some other
guest process to take over.
If async PFs are enabled the fault is retried asap from an async
workqueue. If not, it's retried immediately in the same code path. In
either case the retry will not relinquish the mmap semaphore and will
block on the IO. This is a bad thing, as other mmap semaphore users
now stall as a function of swap or filemap latency.
This patch ensures both the regular and async PF path re-enter the
fault allowing for the mmap semaphore to be relinquished in the case
of IO wait.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Andres Lagar-Cavilla <andreslc@google.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
/me got confused between the kernel and QEMU. In the kernel, you can
only have one module_init function, and it will prevent unloading the
module unless you also have the corresponding module_exit function.
So, commit 80ce163972 (KVM: VFIO: register kvm_device_ops dynamically,
2014-09-02) broke unloading of the kvm module, by adding a module_init
function and no module_exit.
Repair it by making kvm_vfio_ops_init weak, and checking it in
kvm_init.
Cc: Will Deacon <will.deacon@arm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alex Williamson <Alex.Williamson@redhat.com>
Fixes: 80ce163972
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Correct a simple mistake of checking the wrong variable
before a dereference, resulting in the dereference not being
properly protected by rcu_dereference().
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have a dynamic means to register kvm_device_ops, use that
for the VFIO kvm device, instead of relying on the static table.
This is achieved by a module_init call to register the ops with KVM.
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alex Williamson <Alex.Williamson@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Using the new kvm_register_device_ops() interface makes us get rid of
an #ifdef in common code.
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have a dynamic means to register kvm_device_ops, use that
for the ARM VGIC, instead of relying on the static table.
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_ioctl_create_device currently has knowledge of all the device types
and their associated ops. This is fairly inflexible when adding support
for new in-kernel device emulations, so move what we currently have out
into a table, which can support dynamic registration of ops by new
drivers for virtual hardware.
Cc: Alex Williamson <Alex.Williamson@redhat.com>
Cc: Alex Graf <agraf@suse.de>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Read-only memory ranges may be backed by the zero page, so avoid
misidentifying it a a MMIO pfn.
This fixes another issue I identified when testing QEMU+KVM_UEFI, where
a read to an uninitialized emulated NOR flash brought in the zero page,
but mapped as a read-write device region, because kvm_is_mmio_pfn()
misidentifies it as a MMIO pfn due to its PG_reserved bit being set.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: b88657674d ("ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
__kvm_set_memory_region sets r to EINVAL very early.
Doing it again is not necessary. The same is true later on, where
r is assigned -ENOMEM twice.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The first statement of kvm_dev_ioctl is
long r = -EINVAL;
No need to reassign the same value.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The expression `vcpu->spin_loop.in_spin_loop' is always true,
because it is evaluated only when the condition
`!vcpu->spin_loop.in_spin_loop' is false.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vcpu exits and memslot mutations can run concurrently as long as the
vcpu does not aquire the slots mutex. Thus it is theoretically possible
for memslots to change underneath a vcpu that is handling an exit.
If we increment the memslot generation number again after
synchronize_srcu_expedited(), vcpus can safely cache memslot generation
without maintaining a single rcu_dereference through an entire vm exit.
And much of the x86/kvm code does not maintain a single rcu_dereference
of the current memslots during each exit.
We can prevent the following case:
vcpu (CPU 0) | thread (CPU 1)
--------------------------------------------+--------------------------
1 vm exit |
2 srcu_read_unlock(&kvm->srcu) |
3 decide to cache something based on |
old memslots |
4 | change memslots
| (increments generation)
5 | synchronize_srcu(&kvm->srcu);
6 retrieve generation # from new memslots |
7 tag cache with new memslot generation |
8 srcu_read_unlock(&kvm->srcu) |
... |
<action based on cache occurs even |
though the caching decision was based |
on the old memslots> |
... |
<action *continues* to occur until next |
memslot generation change, which may |
be never> |
|
By incrementing the generation after synchronizing with kvm->srcu readers,
we ensure that the generation retrieved in (6) will become invalid soon
after (8).
Keeping the existing increment is not strictly necessary, but we
do keep it and just move it for consistency from update_memslots to
install_new_memslots. It invalidates old cached MMIOs immediately,
instead of having to wait for the end of synchronize_srcu_expedited,
which makes the code more clearly correct in case CPU 1 is preempted
right after synchronize_srcu() returns.
To avoid halving the generation space in SPTEs, always presume that the
low bit of the generation is zero when reconstructing a generation number
out of an SPTE. This effectively disables MMIO caching in SPTEs during
the call to synchronize_srcu_expedited. Using the low bit this way is
somewhat like a seqcount---where the protected thing is a cache, and
instead of retrying we can simply punt if we observe the low bit to be 1.
Cc: stable@vger.kernel.org
Signed-off-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The next patch will give a meaning (a la seqcount) to the low bit of the
generation number. Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().
Cc: stable@vger.kernel.org
Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the beggining was on_each_cpu(), which required an unused argument to
kvm_arch_ops.hardware_{en,dis}able, but this was soon forgotten.
Remove unnecessary arguments that stem from this.
Signed-off-by: Radim KrÄmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The idea between capabilities and the KVM_CHECK_EXTENSION ioctl is that
userspace can, at run-time, determine if a feature is supported or not.
This allows KVM to being supporting a new feature with a new kernel
version without any need to update user space. Unfortunately, since the
definition of KVM_CAP_READONLY_MEM was guarded by #ifdef
__KVM_HAVE_READONLY_MEM, such discovery still required a user space
update.
Therefore, unconditionally export KVM_CAP_READONLY_MEM and change the
in-kernel conditional to rely on __KVM_HAVE_READONLY_MEM.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
To support read-only memory regions on arm and arm64, we have a need to
resolve a gfn to an hva given a pointer to a memslot to avoid looping
through the memslots twice and to reuse the hva error checking of
gfn_to_hva_prot(), add a new gfn_to_hva_memslot_prot() function and
refactor gfn_to_hva_prot() to use this function.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Introduce preempt notifiers for architecture specific code.
Advantage over creating a new notifier in every arch is slightly simpler
code and guaranteed call order with respect to kvm_sched_in.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We dont have to wait for a grace period if there is no oldpid that
we are going to free. putpid also checks for NULL, so this patch
only fences synchronize_rcu.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commits e4d57e1ee1 (KVM: Move irq notifier implementation into
eventfd.c, 2014-06-30) included the irq notifier code unconditionally
in eventfd.c, while it was under CONFIG_HAVE_KVM_IRQCHIP before.
Similarly, commit 297e21053a (KVM: Give IRQFD its own separate enabling
Kconfig option, 2014-06-30) moved code from CONFIG_HAVE_IRQ_ROUTING
to CONFIG_HAVE_KVM_IRQFD but forgot to move the pieces that used to be
under CONFIG_HAVE_KVM_IRQCHIP.
Together, this broke compilation without CONFIG_KVM_XICS. Fix by adding
or changing the #ifdefs so that they point at CONFIG_HAVE_KVM_IRQFD.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, the IRQFD code is conditional on CONFIG_HAVE_KVM_IRQ_ROUTING.
So that we can have the IRQFD code compiled in without having the
IRQ routing code, this creates a new CONFIG_HAVE_KVM_IRQFD, makes
the IRQFD code conditional on it instead of CONFIG_HAVE_KVM_IRQ_ROUTING,
and makes all the platforms that currently select HAVE_KVM_IRQ_ROUTING
also select HAVE_KVM_IRQFD.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Tested-by: Eric Auger <eric.auger@linaro.org>
Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM_CHECK_EXTENSION is only available on the kvm fd today. Unfortunately
on PPC some of the capabilities change depending on the way a VM was created.
So instead we need a way to expose capabilities as VM ioctl, so that we can
see which VM type we're using (HV or PR). To enable this, add the
KVM_CHECK_EXTENSION ioctl to our vm ioctl portfolio.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
In preparation to make the check_extension function available to VM scope
we add a struct kvm * argument to the function header and rename the function
accordingly. It will still be called from the /dev/kvm fd, but with a NULL
argument for struct kvm *.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Pull more scheduler updates from Ingo Molnar:
"Second round of scheduler changes:
- try-to-wakeup and IPI reduction speedups, from Andy Lutomirski
- continued power scheduling cleanups and refactorings, from Nicolas
Pitre
- misc fixes and enhancements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Delete extraneous extern for to_ratio()
sched/idle: Optimize try-to-wake-up IPI
sched/idle: Simplify wake_up_idle_cpu()
sched/idle: Clear polling before descheduling the idle thread
sched, trace: Add a tracepoint for IPI-less remote wakeups
cpuidle: Set polling in poll_idle
sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...)
sched: Rename capacity related flags
sched: Final power vs. capacity cleanups
sched: Remove remaining dubious usage of "power"
sched: Let 'struct sched_group_power' care about CPU capacity
sched/fair: Disambiguate existing/remaining "capacity" usage
sched/fair: Change "has_capacity" to "has_free_capacity"
sched/fair: Remove "power" from 'struct numa_stats'
sched: Fix signedness bug in yield_to()
sched/fair: Use time_after() in record_wakee()
sched/balancing: Reduce the rate of needless idle load balancing
sched/fair: Fix unlocked reads of some cfs_b->quota/period
yield_to() is supposed to return -ESRCH if there is no task to
yield to, but because the type is bool that is the same as returning
true.
The only place I see which cares is kvm_vcpu_on_spin().
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Raghavendra <raghavendra.kt@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Link: http://lkml.kernel.org/r/20140523102042.GA7267@mwanda
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Paolo Bonzini
Christian Borntraeger
David Hildenbrand
Igor Mammedov
Ard Biesheuvel
Radim Krčmář
Dominik Dingel
Wanpeng Li
Linus Torvalds
Andres Lagar-Cavilla
Tang Chen
David Matlack
Sam Bobroff
Christoffer Dall
Will Deacon
Cornelia Huck
Paul Mackerras
Alexander Graf
Dan Carpenter