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Автор SHA1 Сообщение Дата
Ingo Molnar 57ad87ddce Merge branch 'x86/mm' into efi/core, to pick up dependencies
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-01-10 18:53:14 +01:00
Linus Torvalds a313c8e056 PPC:
* Fix a bug where we try to do an ultracall on a system without an ultravisor.
 
 KVM:
 - Fix uninitialised sysreg accessor
 - Fix handling of demand-paged device mappings
 - Stop spamming the console on IMPDEF sysregs
 - Relax mappings of writable memslots
 - Assorted cleanups
 
 MIPS:
 - Now orphan, James Hogan is stepping down
 
 x86:
 - MAINTAINERS change, so long Radim and thanks for all the fish
 - supported CPUID fixes for AMD machines without SPEC_CTRL
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "PPC:
   - Fix a bug where we try to do an ultracall on a system without an
     ultravisor

  KVM:
   - Fix uninitialised sysreg accessor
   - Fix handling of demand-paged device mappings
   - Stop spamming the console on IMPDEF sysregs
   - Relax mappings of writable memslots
   - Assorted cleanups

  MIPS:
   - Now orphan, James Hogan is stepping down

  x86:
   - MAINTAINERS change, so long Radim and thanks for all the fish
   - supported CPUID fixes for AMD machines without SPEC_CTRL"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  MAINTAINERS: remove Radim from KVM maintainers
  MAINTAINERS: Orphan KVM for MIPS
  kvm: x86: Host feature SSBD doesn't imply guest feature AMD_SSBD
  kvm: x86: Host feature SSBD doesn't imply guest feature SPEC_CTRL_SSBD
  KVM: PPC: Book3S HV: Don't do ultravisor calls on systems without ultravisor
  KVM: arm/arm64: Properly handle faulting of device mappings
  KVM: arm64: Ensure 'params' is initialised when looking up sys register
  KVM: arm/arm64: Remove excessive permission check in kvm_arch_prepare_memory_region
  KVM: arm64: Don't log IMP DEF sysreg traps
  KVM: arm64: Sanely ratelimit sysreg messages
  KVM: arm/arm64: vgic: Use wrapper function to lock/unlock all vcpus in kvm_vgic_create()
  KVM: arm/arm64: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()
  KVM: arm/arm64: Get rid of unused arg in cpu_init_hyp_mode()
2019-12-22 10:26:59 -08:00
Paolo Bonzini d68321dec1 PPC KVM fix for 5.5
- Fix a bug where we try to do an ultracall on a system without an
   ultravisor.
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Merge tag 'kvm-ppc-fixes-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master

PPC KVM fix for 5.5

- Fix a bug where we try to do an ultracall on a system without an
  ultravisor.
2019-12-22 13:18:15 +01:00
Jim Mattson 8715f05269 kvm: x86: Host feature SSBD doesn't imply guest feature AMD_SSBD
The host reports support for the synthetic feature X86_FEATURE_SSBD
when any of the three following hardware features are set:
  CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31]
  CPUID.80000008H:EBX.AMD_SSBD[bit 24]
  CPUID.80000008H:EBX.VIRT_SSBD[bit 25]

Either of the first two hardware features implies the existence of the
IA32_SPEC_CTRL MSR, but CPUID.80000008H:EBX.VIRT_SSBD[bit 25] does
not. Therefore, CPUID.80000008H:EBX.AMD_SSBD[bit 24] should only be
set in the guest if CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] or
CPUID.80000008H:EBX.AMD_SSBD[bit 24] is set on the host.

Fixes: 4c6903a0f9 ("KVM: x86: fix reporting of AMD speculation bug CPUID leaf")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Jacob Xu <jacobhxu@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-12-18 17:46:35 +01:00
Jim Mattson 396d2e878f kvm: x86: Host feature SSBD doesn't imply guest feature SPEC_CTRL_SSBD
The host reports support for the synthetic feature X86_FEATURE_SSBD
when any of the three following hardware features are set:
  CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31]
  CPUID.80000008H:EBX.AMD_SSBD[bit 24]
  CPUID.80000008H:EBX.VIRT_SSBD[bit 25]

Either of the first two hardware features implies the existence of the
IA32_SPEC_CTRL MSR, but CPUID.80000008H:EBX.VIRT_SSBD[bit 25] does
not. Therefore, CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] should only be
set in the guest if CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] or
CPUID.80000008H:EBX.AMD_SSBD[bit 24] is set on the host.

Fixes: 0c54914d0c ("KVM: x86: use Intel speculation bugs and features as derived in generic x86 code")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Jacob Xu <jacobhxu@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-12-18 17:46:23 +01:00
Ingo Molnar eb243d1d28 x86/mm/pat: Rename <asm/pat.h> => <asm/memtype.h>
pat.h is a file whose main purpose is to provide the memtype_*() APIs.

PAT is the low level hardware mechanism - but the high level abstraction
is memtype.

So name the header <memtype.h> as well - this goes hand in hand with memtype.c
and memtype_interval.c.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-10 10:12:55 +01:00
Linus Torvalds aedc0650f9 * PPC secure guest support
* small x86 cleanup
 * fix for an x86-specific out-of-bounds write on a ioctl (not guest triggerable,
   data not attacker-controlled)
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more KVM updates from Paolo Bonzini:

 - PPC secure guest support

 - small x86 cleanup

 - fix for an x86-specific out-of-bounds write on a ioctl (not guest
   triggerable, data not attacker-controlled)

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: vmx: Stop wasting a page for guest_msrs
  KVM: x86: fix out-of-bounds write in KVM_GET_EMULATED_CPUID (CVE-2019-19332)
  Documentation: kvm: Fix mention to number of ioctls classes
  powerpc: Ultravisor: Add PPC_UV config option
  KVM: PPC: Book3S HV: Support reset of secure guest
  KVM: PPC: Book3S HV: Handle memory plug/unplug to secure VM
  KVM: PPC: Book3S HV: Radix changes for secure guest
  KVM: PPC: Book3S HV: Shared pages support for secure guests
  KVM: PPC: Book3S HV: Support for running secure guests
  mm: ksm: Export ksm_madvise()
  KVM x86: Move kvm cpuid support out of svm
2019-12-04 11:08:30 -08:00
Jim Mattson 7d73710d9c kvm: vmx: Stop wasting a page for guest_msrs
We will never need more guest_msrs than there are indices in
vmx_msr_index. Thus, at present, the guest_msrs array will not exceed
168 bytes.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-12-04 12:23:27 +01:00
Paolo Bonzini 433f4ba190 KVM: x86: fix out-of-bounds write in KVM_GET_EMULATED_CPUID (CVE-2019-19332)
The bounds check was present in KVM_GET_SUPPORTED_CPUID but not
KVM_GET_EMULATED_CPUID.

Reported-by: syzbot+e3f4897236c4eeb8af4f@syzkaller.appspotmail.com
Fixes: 84cffe499b ("kvm: Emulate MOVBE", 2013-10-29)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-12-04 12:14:41 +01:00
Peter Gonda c1de0f2522 KVM x86: Move kvm cpuid support out of svm
Memory encryption support does not have module parameter dependencies
and can be moved into the general x86 cpuid __do_cpuid_ent function.
This changes maintains current behavior of passing through all of
CPUID.8000001F.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-27 11:39:18 +01:00
Linus Torvalds 1ae78780ed 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 changes in this cycle were:

   - Dynamic tick (nohz) updates, perhaps most notably changes to force
     the tick on when needed due to lengthy in-kernel execution on CPUs
     on which RCU is waiting.

   - Linux-kernel memory consistency model updates.

   - Replace rcu_swap_protected() with rcu_prepace_pointer().

   - Torture-test updates.

   - Documentation updates.

   - Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
  security/safesetid: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/sched: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/netfilter: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/core: Replace rcu_swap_protected() with rcu_replace_pointer()
  bpf/cgroup: Replace rcu_swap_protected() with rcu_replace_pointer()
  fs/afs: Replace rcu_swap_protected() with rcu_replace_pointer()
  drivers/scsi: Replace rcu_swap_protected() with rcu_replace_pointer()
  drm/i915: Replace rcu_swap_protected() with rcu_replace_pointer()
  x86/kvm/pmu: Replace rcu_swap_protected() with rcu_replace_pointer()
  rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()
  rcu: Suppress levelspread uninitialized messages
  rcu: Fix uninitialized variable in nocb_gp_wait()
  rcu: Update descriptions for rcu_future_grace_period tracepoint
  rcu: Update descriptions for rcu_nocb_wake tracepoint
  rcu: Remove obsolete descriptions for rcu_barrier tracepoint
  rcu: Ensure that ->rcu_urgent_qs is set before resched IPI
  workqueue: Convert for_each_wq to use built-in list check
  rcu: Several rcu_segcblist functions can be static
  rcu: Remove unused function hlist_bl_del_init_rcu()
  Documentation: Rename rcu_node_context_switch() to rcu_note_context_switch()
  ...
2019-11-26 15:42:43 -08:00
Linus Torvalds 3f59dbcace Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "The main kernel side changes in this cycle were:

   - Various Intel-PT updates and optimizations (Alexander Shishkin)

   - Prohibit kprobes on Xen/KVM emulate prefixes (Masami Hiramatsu)

   - Add support for LSM and SELinux checks to control access to the
     perf syscall (Joel Fernandes)

   - Misc other changes, optimizations, fixes and cleanups - see the
     shortlog for details.

  There were numerous tooling changes as well - 254 non-merge commits.
  Here are the main changes - too many to list in detail:

   - Enhancements to core tooling infrastructure, perf.data, libperf,
     libtraceevent, event parsing, vendor events, Intel PT, callchains,
     BPF support and instruction decoding.

   - There were updates to the following tools:

        perf annotate
        perf diff
        perf inject
        perf kvm
        perf list
        perf maps
        perf parse
        perf probe
        perf record
        perf report
        perf script
        perf stat
        perf test
        perf trace

   - And a lot of other changes: please see the shortlog and Git log for
     more details"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (279 commits)
  perf parse: Fix potential memory leak when handling tracepoint errors
  perf probe: Fix spelling mistake "addrees" -> "address"
  libtraceevent: Fix memory leakage in copy_filter_type
  libtraceevent: Fix header installation
  perf intel-bts: Does not support AUX area sampling
  perf intel-pt: Add support for decoding AUX area samples
  perf intel-pt: Add support for recording AUX area samples
  perf pmu: When using default config, record which bits of config were changed by the user
  perf auxtrace: Add support for queuing AUX area samples
  perf session: Add facility to peek at all events
  perf auxtrace: Add support for dumping AUX area samples
  perf inject: Cut AUX area samples
  perf record: Add aux-sample-size config term
  perf record: Add support for AUX area sampling
  perf auxtrace: Add support for AUX area sample recording
  perf auxtrace: Move perf_evsel__find_pmu()
  perf record: Add a function to test for kernel support for AUX area sampling
  perf tools: Add kernel AUX area sampling definitions
  perf/core: Make the mlock accounting simple again
  perf report: Jump to symbol source view from total cycles view
  ...
2019-11-26 15:04:47 -08:00
Linus Torvalds ab851d49f6 Merge branch 'x86-iopl-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 iopl updates from Ingo Molnar:
 "This implements a nice simplification of the iopl and ioperm code that
  Thomas Gleixner discovered: we can implement the IO privilege features
  of the iopl system call by using the IO permission bitmap in
  permissive mode, while trapping CLI/STI/POPF/PUSHF uses in user-space
  if they change the interrupt flag.

  This implements that feature, with testing facilities and related
  cleanups"

[ "Simplification" may be an over-statement. The main goal is to avoid
  the cli/sti of iopl by effectively implementing the IO port access
  parts of iopl in terms of ioperm.

  This may end up not workign well in case people actually depend on
  cli/sti being available, or if there are mixed uses of iopl and
  ioperm. We will see..       - Linus ]

* 'x86-iopl-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  x86/ioperm: Fix use of deprecated config option
  x86/entry/32: Clarify register saving in __switch_to_asm()
  selftests/x86/iopl: Extend test to cover IOPL emulation
  x86/ioperm: Extend IOPL config to control ioperm() as well
  x86/iopl: Remove legacy IOPL option
  x86/iopl: Restrict iopl() permission scope
  x86/iopl: Fixup misleading comment
  selftests/x86/ioperm: Extend testing so the shared bitmap is exercised
  x86/ioperm: Share I/O bitmap if identical
  x86/ioperm: Remove bitmap if all permissions dropped
  x86/ioperm: Move TSS bitmap update to exit to user work
  x86/ioperm: Add bitmap sequence number
  x86/ioperm: Move iobitmap data into a struct
  x86/tss: Move I/O bitmap data into a seperate struct
  x86/io: Speedup schedule out of I/O bitmap user
  x86/ioperm: Avoid bitmap allocation if no permissions are set
  x86/ioperm: Simplify first ioperm() invocation logic
  x86/iopl: Cleanup include maze
  x86/tss: Fix and move VMX BUILD_BUG_ON()
  x86/cpu: Unify cpu_init()
  ...
2019-11-26 11:12:02 -08:00
Linus Torvalds 1d87200446 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Cross-arch changes to move the linker sections for NOTES and
     EXCEPTION_TABLE into the RO_DATA area, where they belong on most
     architectures. (Kees Cook)

   - Switch the x86 linker fill byte from x90 (NOP) to 0xcc (INT3), to
     trap jumps into the middle of those padding areas instead of
     sliding execution. (Kees Cook)

   - A thorough cleanup of symbol definitions within x86 assembler code.
     The rather randomly named macros got streamlined around a
     (hopefully) straightforward naming scheme:

        SYM_START(name, linkage, align...)
        SYM_END(name, sym_type)

        SYM_FUNC_START(name)
        SYM_FUNC_END(name)

        SYM_CODE_START(name)
        SYM_CODE_END(name)

        SYM_DATA_START(name)
        SYM_DATA_END(name)

     etc - with about three times of these basic primitives with some
     label, local symbol or attribute variant, expressed via postfixes.

     No change in functionality intended. (Jiri Slaby)

   - Misc other changes, cleanups and smaller fixes"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (67 commits)
  x86/entry/64: Remove pointless jump in paranoid_exit
  x86/entry/32: Remove unused resume_userspace label
  x86/build/vdso: Remove meaningless CFLAGS_REMOVE_*.o
  m68k: Convert missed RODATA to RO_DATA
  x86/vmlinux: Use INT3 instead of NOP for linker fill bytes
  x86/mm: Report actual image regions in /proc/iomem
  x86/mm: Report which part of kernel image is freed
  x86/mm: Remove redundant address-of operators on addresses
  xtensa: Move EXCEPTION_TABLE to RO_DATA segment
  powerpc: Move EXCEPTION_TABLE to RO_DATA segment
  parisc: Move EXCEPTION_TABLE to RO_DATA segment
  microblaze: Move EXCEPTION_TABLE to RO_DATA segment
  ia64: Move EXCEPTION_TABLE to RO_DATA segment
  h8300: Move EXCEPTION_TABLE to RO_DATA segment
  c6x: Move EXCEPTION_TABLE to RO_DATA segment
  arm64: Move EXCEPTION_TABLE to RO_DATA segment
  alpha: Move EXCEPTION_TABLE to RO_DATA segment
  x86/vmlinux: Move EXCEPTION_TABLE to RO_DATA segment
  x86/vmlinux: Actually use _etext for the end of the text segment
  vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
  ...
2019-11-26 10:42:40 -08:00
Ingo Molnar ceb9e77324 Merge branch 'x86/core' into perf/core, to resolve conflicts and to pick up completed topic tree
Conflicts:
	tools/perf/check-headers.sh

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-25 09:09:27 +01:00
Jim Mattson 85c9aae9ac kvm: nVMX: Relax guest IA32_FEATURE_CONTROL constraints
Commit 37e4c997da ("KVM: VMX: validate individual bits of guest
MSR_IA32_FEATURE_CONTROL") broke the KVM_SET_MSRS ABI by instituting
new constraints on the data values that kvm would accept for the guest
MSR, IA32_FEATURE_CONTROL. Perhaps these constraints should have been
opt-in via a new KVM capability, but they were applied
indiscriminately, breaking at least one existing hypervisor.

Relax the constraints to allow either or both of
FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX and
FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX to be set when nVMX is
enabled. This change is sufficient to fix the aforementioned breakage.

Fixes: 37e4c997da ("KVM: VMX: validate individual bits of guest MSR_IA32_FEATURE_CONTROL")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-23 11:34:46 +01:00
Sean Christopherson ad5996d9a0 KVM: x86: Grab KVM's srcu lock when setting nested state
Acquire kvm->srcu for the duration of ->set_nested_state() to fix a bug
where nVMX derefences ->memslots without holding ->srcu or ->slots_lock.

The other half of nested migration, ->get_nested_state(), does not need
to acquire ->srcu as it is a purely a dump of internal KVM (and CPU)
state to userspace.

Detected as an RCU lockdep splat that is 100% reproducible by running
KVM's state_test selftest with CONFIG_PROVE_LOCKING=y.  Note that the
failing function, kvm_is_visible_gfn(), is only checking the validity of
a gfn, it's not actually accessing guest memory (which is more or less
unsupported during vmx_set_nested_state() due to incorrect MMU state),
i.e. vmx_set_nested_state() itself isn't fundamentally broken.  In any
case, setting nested state isn't a fast path so there's no reason to go
out of our way to avoid taking ->srcu.

  =============================
  WARNING: suspicious RCU usage
  5.4.0-rc7+ #94 Not tainted
  -----------------------------
  include/linux/kvm_host.h:626 suspicious rcu_dereference_check() usage!

               other info that might help us debug this:

  rcu_scheduler_active = 2, debug_locks = 1
  1 lock held by evmcs_test/10939:
   #0: ffff88826ffcb800 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x85/0x630 [kvm]

  stack backtrace:
  CPU: 1 PID: 10939 Comm: evmcs_test Not tainted 5.4.0-rc7+ #94
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  Call Trace:
   dump_stack+0x68/0x9b
   kvm_is_visible_gfn+0x179/0x180 [kvm]
   mmu_check_root+0x11/0x30 [kvm]
   fast_cr3_switch+0x40/0x120 [kvm]
   kvm_mmu_new_cr3+0x34/0x60 [kvm]
   nested_vmx_load_cr3+0xbd/0x1f0 [kvm_intel]
   nested_vmx_enter_non_root_mode+0xab8/0x1d60 [kvm_intel]
   vmx_set_nested_state+0x256/0x340 [kvm_intel]
   kvm_arch_vcpu_ioctl+0x491/0x11a0 [kvm]
   kvm_vcpu_ioctl+0xde/0x630 [kvm]
   do_vfs_ioctl+0xa2/0x6c0
   ksys_ioctl+0x66/0x70
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x54/0x200
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7f59a2b95f47

Fixes: 8fcc4b5923 ("kvm: nVMX: Introduce KVM_CAP_NESTED_STATE")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-23 11:30:15 +01:00
Sean Christopherson 05c19c2fe1 KVM: x86: Open code shared_msr_update() in its only caller
Fold shared_msr_update() into its sole user to eliminate its pointless
bounds check, its godawful printk, its misleading comment (it's called
under a global lock), and its woefully inaccurate name.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-23 11:29:38 +01:00
Sean Christopherson 24885d1d79 KVM: x86: Remove a spurious export of a static function
A recent change inadvertently exported a static function, which results
in modpost throwing a warning.  Fix it.

Fixes: cbbaa2727a ("KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-23 11:28:59 +01:00
Paolo Bonzini c50d8ae3a1 KVM: x86: create mmu/ subdirectory
Preparatory work for shattering mmu.c into multiple files.  Besides making it easier
to follow, this will also make it possible to write unit tests for various parts.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 12:03:50 +01:00
Liran Alon 0155b2b91b KVM: nVMX: Remove unnecessary TLB flushes on L1<->L2 switches when L1 use apic-access-page
According to Intel SDM section 28.3.3.3/28.3.3.4 Guidelines for Use
of the INVVPID/INVEPT Instruction, the hypervisor needs to execute
INVVPID/INVEPT X in case CPU executes VMEntry with VPID/EPTP X and
either: "Virtualize APIC accesses" VM-execution control was changed
from 0 to 1, OR the value of apic_access_page was changed.

In the nested case, the burden falls on L1, unless L0 enables EPT in
vmcs02 but L1 enables neither EPT nor VPID in vmcs12.  For this reason
prepare_vmcs02() and load_vmcs12_host_state() have special code to
request a TLB flush in case L1 does not use EPT but it uses
"virtualize APIC accesses".

This special case however is not necessary. On a nested vmentry the
physical TLB will already be flushed except if all the following apply:

* L0 uses VPID

* L1 uses VPID

* L0 can guarantee TLB entries populated while running L1 are tagged
differently than TLB entries populated while running L2.

If the first condition is false, the processor will flush the TLB
on vmentry to L2.  If the second or third condition are false,
prepare_vmcs02() will request KVM_REQ_TLB_FLUSH.  However, even
if both are true, no extra TLB flush is needed to handle the APIC
access page:

* if L1 doesn't use VPID, the second condition doesn't hold and the
TLB will be flushed anyway.

* if L1 uses VPID, it has to flush the TLB itself with INVVPID and
section 28.3.3.3 doesn't apply to L0.

* even INVEPT is not needed because, if L0 uses EPT, it uses different
EPTP when running L2 than L1 (because guest_mode is part of mmu-role).
In this case SDM section 28.3.3.4 doesn't apply.

Similarly, examining nested_vmx_vmexit()->load_vmcs12_host_state(),
one could note that L0 won't flush TLB only in cases where SDM sections
28.3.3.3 and 28.3.3.4 don't apply.  In particular, if L0 uses different
VPIDs for L1 and L2 (i.e. vmx->vpid != vmx->nested.vpid02), section
28.3.3.3 doesn't apply.

Thus, remove this flush from prepare_vmcs02() and nested_vmx_vmexit().

Side-note: This patch can be viewed as removing parts of commit
fb6c819843 ("kvm: vmx: Flush TLB when the APIC-access address changes”)
that is not relevant anymore since commit
1313cc2bd8 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role”).
i.e. The first commit assumes that if L0 use EPT and L1 doesn’t use EPT,
then L0 will use same EPTP for both L0 and L1. Which indeed required
L0 to execute INVEPT before entering L2 guest. This assumption is
not true anymore since when guest_mode was added to mmu-role.

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 12:03:50 +01:00
Mao Wenan db5a95ec16 KVM: x86: remove set but not used variable 'called'
Fixes gcc '-Wunused-but-set-variable' warning:

arch/x86/kvm/x86.c: In function kvm_make_scan_ioapic_request_mask:
arch/x86/kvm/x86.c:7911:7: warning: variable called set but not
used [-Wunused-but-set-variable]

It is not used since commit 7ee30bc132 ("KVM: x86: deliver KVM
IOAPIC scan request to target vCPUs")

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Fixes: 7ee30bc132 ("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 12:03:49 +01:00
Liran Alon b11494bcab KVM: nVMX: Do not mark vmcs02->apic_access_page as dirty when unpinning
vmcs->apic_access_page is simply a token that the hypervisor puts into
the PFN of a 4KB EPTE (or PTE if using shadow-paging) that triggers
APIC-access VMExit or APIC virtualization logic whenever a CPU running
in VMX non-root mode read/write from/to this PFN.

As every write either triggers an APIC-access VMExit or write is
performed on vmcs->virtual_apic_page, the PFN pointed to by
vmcs->apic_access_page should never actually be touched by CPU.

Therefore, there is no need to mark vmcs02->apic_access_page as dirty
after unpin it on L2->L1 emulated VMExit or when L1 exit VMX operation.

Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 12:03:48 +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 b07a5c53d4 KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it
If X86_FEATURE_RTM is disabled, the guest should not be able to access
MSR_IA32_TSX_CTRL.  We can therefore use it in KVM to force all
transactions from the guest to abort.

Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 10:01:02 +01:00
Paolo Bonzini c11f83e062 KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality
The current guest mitigation of TAA is both too heavy and not really
sufficient.  It is too heavy because it will cause some affected CPUs
(those that have MDS_NO but lack TAA_NO) to fall back to VERW and
get the corresponding slowdown.  It is not really sufficient because
it will cause the MDS_NO bit to disappear upon microcode update, so
that VMs started before the microcode update will not be runnable
anymore afterwards, even with tsx=on.

Instead, if tsx=on on the host, we can emulate MSR_IA32_TSX_CTRL for
the guest and let it run without the VERW mitigation.  Even though
MSR_IA32_TSX_CTRL is quite heavyweight, and we do not want to write
it on every vmentry, we can use the shared MSR functionality because
the host kernel need not protect itself from TSX-based side-channels.

Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 10:00:59 +01:00
Paolo Bonzini edef5c36b0 KVM: x86: implement MSR_IA32_TSX_CTRL effect on CPUID
Because KVM always emulates CPUID, the CPUID clear bit
(bit 1) of MSR_IA32_TSX_CTRL must be emulated "manually"
by the hypervisor when performing said emulation.

Right now neither kvm-intel.ko nor kvm-amd.ko implement
MSR_IA32_TSX_CTRL but this will change in the next patch.

Reviewed-by: Jim Mattson <jmattson@google.com>
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 09:59:31 +01:00
Paolo Bonzini de1fca5d6e KVM: x86: do not modify masked bits of shared MSRs
"Shared MSRs" are guest MSRs that are written to the host MSRs but
keep their value until the next return to userspace.  They support
a mask, so that some bits keep the host value, but this mask is
only used to skip an unnecessary MSR write and the value written
to the MSR is always the guest MSR.

Fix this and, while at it, do not update smsr->values[slot].curr if
for whatever reason the wrmsr fails.  This should only happen due to
reserved bits, so the value written to smsr->values[slot].curr
will not match when the user-return notifier and the host value will
always be restored.  However, it is untidy and in rare cases this
can actually avoid spurious WRMSRs on return to userspace.

Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 09:59:22 +01:00
Paolo Bonzini cbbaa2727a KVM: x86: fix presentation of TSX feature in ARCH_CAPABILITIES
KVM does not implement MSR_IA32_TSX_CTRL, so it must not be presented
to the guests.  It is also confusing to have !ARCH_CAP_TSX_CTRL_MSR &&
!RTM && ARCH_CAP_TAA_NO: lack of MSR_IA32_TSX_CTRL suggests TSX was not
hidden (it actually was), yet the value says that TSX is not vulnerable
to microarchitectural data sampling.  Fix both.

Cc: stable@vger.kernel.org
Tested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-21 09:59:10 +01:00
Liran Alon 992edeaefe KVM: nVMX: Assume TLB entries of L1 and L2 are tagged differently if L0 use EPT
Since commit 1313cc2bd8 ("kvm: mmu: Add guest_mode to kvm_mmu_page_role"),
guest_mode was added to mmu-role and therefore if L0 use EPT, it will
always run L1 and L2 with different EPTP. i.e. EPTP01!=EPTP02.

Because TLB entries are tagged with EP4TA, KVM can assume
TLB entries populated while running L2 are tagged differently
than TLB entries populated while running L1.

Therefore, update nested_has_guest_tlb_tag() to consider if
L0 use EPT instead of if L1 use EPT.

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-20 14:23:27 +01:00
Liran Alon 5637f60b68 KVM: x86: Unexport kvm_vcpu_reload_apic_access_page()
The function is only used in kvm.ko module.

Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-20 14:23:26 +01:00
Chenyi Qiang c79eb77554 KVM: nVMX: add CR4_LA57 bit to nested CR4_FIXED1
When L1 guest uses 5-level paging, it fails vm-entry to L2 due to
invalid host-state. It needs to add CR4_LA57 bit to nested CR4_FIXED1
MSR.

Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-20 14:23:26 +01:00
Liran Alon cc87767097 KVM: nVMX: Use semi-colon instead of comma for exit-handlers initialization
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-20 14:23:25 +01:00
Nitesh Narayan Lal 9a2ae9f6b6 KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap
Not zeroing the bitmap used for identifying the destination vCPUs for an
IOAPIC scan request in fixed delivery mode could lead to waking up unwanted
vCPUs. This patch zeroes the vCPU bitmap before passing it to
kvm_bitmap_or_dest_vcpus(), which is responsible for setting the bitmap
with the bits corresponding to the destination vCPUs.

Fixes: 7ee30bc132c6("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-20 14:23:24 +01:00
Thomas Gleixner 6b546e1c9a x86/tss: Fix and move VMX BUILD_BUG_ON()
The BUILD_BUG_ON(IO_BITMAP_OFFSET - 1 == 0x67) in the VMX code is bogus in
two aspects:

1) This wants to be in generic x86 code simply to catch issues even when
   VMX is disabled in Kconfig.

2) The IO_BITMAP_OFFSET is not the right thing to check because it makes
   asssumptions about the layout of tss_struct. Nothing requires that the
   I/O bitmap is placed right after x86_tss, which is the hardware mandated
   tss structure. It pointlessly makes restrictions on the struct
   tss_struct layout.

The proper thing to check is:

    - Offset of x86_tss in tss_struct is 0
    - Size of x86_tss == 0x68

Move it to the other build time TSS checks and make it do the right thing.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
2019-11-16 11:24:00 +01:00
Nitesh Narayan Lal 7ee30bc132 KVM: x86: deliver KVM IOAPIC scan request to target vCPUs
In IOAPIC fixed delivery mode instead of flushing the scan
requests to all vCPUs, we should only send the requests to
vCPUs specified within the destination field.

This patch introduces kvm_get_dest_vcpus_mask() API which
retrieves an array of target vCPUs by using
kvm_apic_map_get_dest_lapic() and then based on the
vcpus_idx, it sets the bit in a bitmap. However, if the above
fails kvm_get_dest_vcpus_mask() finds the target vCPUs by
traversing all available vCPUs. Followed by setting the
bits in the bitmap.

If we had different vCPUs in the previous request for the
same redirection table entry then bits corresponding to
these vCPUs are also set. This to done to keep
ioapic_handled_vectors synchronized.

This bitmap is then eventually passed on to
kvm_make_vcpus_request_mask() to generate a masked request
only for the target vCPUs.

This would enable us to reduce the latency overhead on isolated
vCPUs caused by the IPI to process due to KVM_REQ_IOAPIC_SCAN.

Suggested-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:22 +01:00
Aaron Lewis 662f1d1d19 KVM: nVMX: Add support for capturing highest observable L2 TSC
The L1 hypervisor may include the IA32_TIME_STAMP_COUNTER MSR in the
vmcs12 MSR VM-exit MSR-store area as a way of determining the highest
TSC value that might have been observed by L2 prior to VM-exit. The
current implementation does not capture a very tight bound on this
value.  To tighten the bound, add the IA32_TIME_STAMP_COUNTER MSR to the
vmcs02 VM-exit MSR-store area whenever it appears in the vmcs12 VM-exit
MSR-store area.  When L0 processes the vmcs12 VM-exit MSR-store area
during the emulation of an L2->L1 VM-exit, special-case the
IA32_TIME_STAMP_COUNTER MSR, using the value stored in the vmcs02
VM-exit MSR-store area to derive the value to be stored in the vmcs12
VM-exit MSR-store area.

Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:20 +01:00
Aaron Lewis ef0fbcac3f kvm: vmx: Rename function find_msr() to vmx_find_msr_index()
Rename function find_msr() to vmx_find_msr_index() in preparation for an
upcoming patch where we export it and use it in nested.c.

Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:20 +01:00
Aaron Lewis 7cfe0526fd kvm: vmx: Rename NR_AUTOLOAD_MSRS to NR_LOADSTORE_MSRS
Rename NR_AUTOLOAD_MSRS to NR_LOADSTORE_MSRS.  This needs to be done
due to the addition of the MSR-autostore area that will be added in a
future patch.  After that the name AUTOLOAD will no longer make sense.

Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:19 +01:00
Aaron Lewis 365d3d55d6 kvm: nested: Introduce read_and_check_msr_entry()
Add the function read_and_check_msr_entry() which just pulls some code
out of nested_vmx_store_msr().  This will be useful as reusable code in
upcoming patches.

Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:18 +01:00
Paolo Bonzini d4069dbeb5 KVM: nVMX: mark functions in the header as "static inline"
Correct a small inaccuracy in the shattering of vmx.c, which becomes
visible now that pmu_intel.c includes nested.h.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:17 +01:00
Oliver Upton 03a8871add KVM: nVMX: Expose load IA32_PERF_GLOBAL_CTRL VM-{Entry,Exit} control
The "load IA32_PERF_GLOBAL_CTRL" bit for VM-entry and VM-exit should
only be exposed to the guest if IA32_PERF_GLOBAL_CTRL is a valid MSR.
Create a new helper to allow pmu_refresh() to update the VM-Entry and
VM-Exit controls to ensure PMU values are initialized when performing
the is_valid_msr() check.

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:16 +01:00
Oliver Upton 71f7347025 KVM: nVMX: Load GUEST_IA32_PERF_GLOBAL_CTRL MSR on VM-Entry
Add condition to prepare_vmcs02 which loads IA32_PERF_GLOBAL_CTRL on
VM-entry if the "load IA32_PERF_GLOBAL_CTRL" bit on the VM-entry control
is set. Use SET_MSR_OR_WARN() rather than directly writing to the field
to avoid overwrite by atomic_switch_perf_msrs().

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:16 +01:00
Oliver Upton 458151f65b KVM: nVMX: Use kvm_set_msr to load IA32_PERF_GLOBAL_CTRL on VM-Exit
The existing implementation for loading the IA32_PERF_GLOBAL_CTRL MSR
on VM-exit was incorrect, as the next call to atomic_switch_perf_msrs()
could cause this value to be overwritten. Instead, call kvm_set_msr()
which will allow atomic_switch_perf_msrs() to correctly set the values.

Define a macro, SET_MSR_OR_WARN(), to set the MSR with kvm_set_msr()
and WARN on failure.

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:15 +01:00
Oliver Upton c547cb6f78 KVM: nVMX: Check HOST_IA32_PERF_GLOBAL_CTRL on VM-Entry
Add a consistency check on nested vm-entry for host's
IA32_PERF_GLOBAL_CTRL from vmcs12. Per Intel's SDM Vol 3 26.2.2:

  If the "load IA32_PERF_GLOBAL_CTRL"
  VM-exit control is 1, bits reserved in the IA32_PERF_GLOBAL_CTRL
  MSR must be 0 in the field for that register"

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:14 +01:00
Oliver Upton bfc6ad6ab3 KVM: nVMX: Check GUEST_IA32_PERF_GLOBAL_CTRL on VM-Entry
Add condition to nested_vmx_check_guest_state() to check the validity of
GUEST_IA32_PERF_GLOBAL_CTRL. Per Intel's SDM Vol 3 26.3.1.1:

  If the "load IA32_PERF_GLOBAL_CTRL" VM-entry control is 1, bits
  reserved in the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the field for that
  register.

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:13 +01:00
Oliver Upton 9477f4449b KVM: VMX: Add helper to check reserved bits in IA32_PERF_GLOBAL_CTRL
Create a helper function to check the validity of a proposed value for
IA32_PERF_GLOBAL_CTRL from the existing check in intel_pmu_set_msr().

Per Intel's SDM, the reserved bits in IA32_PERF_GLOBAL_CTRL must be
cleared for the corresponding host/guest state fields.

Suggested-by: Jim Mattson <jmattson@google.com>
Co-developed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:13 +01:00
Liran Alon 1924242b2a KVM: x86: Optimization: Requst TLB flush in fast_cr3_switch() instead of do it directly
When KVM emulates a nested VMEntry (L1->L2 VMEntry), it switches mmu root
page. If nEPT is used, this will happen from
kvm_init_shadow_ept_mmu()->__kvm_mmu_new_cr3() and otherwise it will
happpen from nested_vmx_load_cr3()->kvm_mmu_new_cr3(). Either case,
__kvm_mmu_new_cr3() will use fast_cr3_switch() in attempt to switch to a
previously cached root page.

In case fast_cr3_switch() finds a matching cached root page, it will
set it in mmu->root_hpa and request KVM_REQ_LOAD_CR3 such that on
next entry to guest, KVM will set root HPA in appropriate hardware
fields (e.g. vmcs->eptp). In addition, fast_cr3_switch() calls
kvm_x86_ops->tlb_flush() in order to flush TLB as MMU root page
was replaced.

This works as mmu->root_hpa, which vmx_flush_tlb() use, was
already replaced in cached_root_available(). However, this may
result in unnecessary INVEPT execution because a KVM_REQ_TLB_FLUSH
may have already been requested. For example, by prepare_vmcs02()
in case L1 don't use VPID.

Therefore, change fast_cr3_switch() to just request TLB flush on
next entry to guest.

Reviewed-by: Bhavesh Davda <bhavesh.davda@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:11 +01:00
Like Xu b35e5548b4 KVM: x86/vPMU: Add lazy mechanism to release perf_event per vPMC
Currently, a host perf_event is created for a vPMC functionality emulation.
It’s unpredictable to determine if a disabled perf_event will be reused.
If they are disabled and are not reused for a considerable period of time,
those obsolete perf_events would increase host context switch overhead that
could have been avoided.

If the guest doesn't WRMSR any of the vPMC's MSRs during an entire vcpu
sched time slice, and its independent enable bit of the vPMC isn't set,
we can predict that the guest has finished the use of this vPMC, and then
do request KVM_REQ_PMU in kvm_arch_sched_in and release those perf_events
in the first call of kvm_pmu_handle_event() after the vcpu is scheduled in.

This lazy mechanism delays the event release time to the beginning of the
next scheduled time slice if vPMC's MSRs aren't changed during this time
slice. If guest comes back to use this vPMC in next time slice, a new perf
event would be re-created via perf_event_create_kernel_counter() as usual.

Suggested-by: Wei Wang <wei.w.wang@intel.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:10 +01:00
Like Xu a6da0d77e9 KVM: x86/vPMU: Reuse perf_event to avoid unnecessary pmc_reprogram_counter
The perf_event_create_kernel_counter() in the pmc_reprogram_counter() is
a heavyweight and high-frequency operation, especially when host disables
the watchdog (maximum 21000000 ns) which leads to an unacceptable latency
of the guest NMI handler. It limits the use of vPMUs in the guest.

When a vPMC is fully enabled, the legacy reprogram_*_counter() would stop
and release its existing perf_event (if any) every time EVEN in most cases
almost the same requested perf_event will be created and configured again.

For each vPMC, if the reuqested config ('u64 eventsel' for gp and 'u8 ctrl'
for fixed) is the same as its current config AND a new sample period based
on pmc->counter is accepted by host perf interface, the current event could
be reused safely as a new created one does. Otherwise, do release the
undesirable perf_event and reprogram a new one as usual.

It's light-weight to call pmc_pause_counter (disable, read and reset event)
and pmc_resume_counter (recalibrate period and re-enable event) as guest
expects instead of release-and-create again on any condition. Compared to
use the filterable event->attr or hw.config, a new 'u64 current_config'
field is added to save the last original programed config for each vPMC.

Based on this implementation, the number of calls to pmc_reprogram_counter
is reduced by ~82.5% for a gp sampling event and ~99.9% for a fixed event.
In the usage of multiplexing perf sampling mode, the average latency of the
guest NMI handler is reduced from 104923 ns to 48393 ns (~2.16x speed up).
If host disables watchdog, the minimum latecy of guest NMI handler could be
speed up at ~3413x (from 20407603 to 5979 ns) and at ~786x in the average.

Suggested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:44:09 +01:00