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  1. 03 6月, 2021 2 次提交
  3. 09 4月, 2021 1 次提交
  5. 09 3月, 2021 1 次提交
  7. 13 11月, 2020 1 次提交
  9. 22 10月, 2020 1 次提交
  11. 28 9月, 2020 2 次提交
    • A
      KVM: x86: Allow deflecting unknown MSR accesses to user space · 1ae09954
      由 Alexander Graf 提交于 
      MSRs are weird. Some of them are normal control registers, such as EFER.
Some however are registers that really are model specific, not very
interesting to virtualization workloads, and not performance critical.
Others again are really just windows into package configuration.

Out of these MSRs, only the first category is necessary to implement in
kernel space. Rarely accessed MSRs, MSRs that should be fine tunes against
certain CPU models and MSRs that contain information on the package level
are much better suited for user space to process. However, over time we have
accumulated a lot of MSRs that are not the first category, but still handled
by in-kernel KVM code.

This patch adds a generic interface to handle WRMSR and RDMSR from user
space. With this, any future MSR that is part of the latter categories can
be handled in user space.

Furthermore, it allows us to replace the existing "ignore_msrs" logic with
something that applies per-VM rather than on the full system. That way you
can run productive VMs in parallel to experimental ones where you don't care
about proper MSR handling.
Signed-off-by: NAlexander Graf <graf@amazon.com>
Reviewed-by: NJim Mattson <jmattson@google.com>

Message-Id: <20200925143422.21718-3-graf@amazon.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      1ae09954
    • R
      KVM: x86: emulating RDPID failure shall return #UD rather than #GP · a9e2e0ae
      由 Robert Hoo 提交于 
      Per Intel's SDM, RDPID takes a #UD if it is unsupported, which is more or
less what KVM is emulating when MSR_TSC_AUX is not available.  In fact,
there are no scenarios in which RDPID is supposed to #GP.

Fixes: fb6d4d34 ("KVM: x86: emulate RDPID")
Signed-off-by: NRobert Hoo <robert.hu@linux.intel.com>
Message-Id: <1598581422-76264-1-git-send-email-robert.hu@linux.intel.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      a9e2e0ae
  13. 13 9月, 2020 1 次提交
  15. 24 8月, 2020 1 次提交
  17. 05 6月, 2020 1 次提交
  19. 14 5月, 2020 1 次提交
  21. 17 3月, 2020 4 次提交
  23. 04 3月, 2020 1 次提交
    • V
      KVM: x86: clear stale x86_emulate_ctxt->intercept value · 342993f9
      由 Vitaly Kuznetsov 提交于 
      After commit 07721fee ("KVM: nVMX: Don't emulate instructions in guest
mode") Hyper-V guests on KVM stopped booting with:

 kvm_nested_vmexit:    rip fffff802987d6169 reason EPT_VIOLATION info1 181
    info2 0 int_info 0 int_info_err 0
 kvm_page_fault:       address febd0000 error_code 181
 kvm_emulate_insn:     0:fffff802987d6169: f3 a5
 kvm_emulate_insn:     0:fffff802987d6169: f3 a5 FAIL
 kvm_inj_exception:    #UD (0x0)

"f3 a5" is a "rep movsw" instruction, which should not be intercepted
at all.  Commit c44b4c6a ("KVM: emulate: clean up initializations in
init_decode_cache") reduced the number of fields cleared by
init_decode_cache() claiming that they are being cleared elsewhere,
'intercept', however, is left uncleared if the instruction does not have
any of the "slow path" flags (NotImpl, Stack, Op3264, Sse, Mmx, CheckPerm,
NearBranch, No16 and of course Intercept itself).

Fixes: c44b4c6a ("KVM: emulate: clean up initializations in init_decode_cache")
Fixes: 07721fee ("KVM: nVMX: Don't emulate instructions in guest mode")
Cc: stable@vger.kernel.org
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      342993f9
  25. 21 2月, 2020 1 次提交
  27. 28 1月, 2020 6 次提交
  29. 21 1月, 2020 1 次提交
    • S
      KVM: x86: Add dedicated emulator helpers for querying CPUID features · 5ae78e95
      由 Sean Christopherson 提交于 
      Add feature-specific helpers for querying guest CPUID support from the
emulator instead of having the emulator do a full CPUID and perform its
own bit tests.  The primary motivation is to eliminate the emulator's
usage of bit() so that future patches can add more extensive build-time
assertions on the usage of bit() without having to expose yet more code
to the emulator.

Note, providing a generic guest_cpuid_has() to the emulator doesn't work
due to the existing built-time assertions in guest_cpuid_has(), which
require the feature being checked to be a compile-time constant.

No functional change intended.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      5ae78e95
  31. 15 11月, 2019 1 次提交
  33. 12 9月, 2019 1 次提交
  35. 22 8月, 2019 2 次提交
  37. 19 7月, 2019 1 次提交
  39. 19 6月, 2019 1 次提交
  41. 18 6月, 2019 1 次提交
  43. 16 4月, 2019 5 次提交
    • S
      KVM: x86: Always use 32-bit SMRAM save state for 32-bit kernels · b68f3cc7
      由 Sean Christopherson 提交于 
      Invoking the 64-bit variation on a 32-bit kenrel will crash the guest,
trigger a WARN, and/or lead to a buffer overrun in the host, e.g.
rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and
thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64.

KVM allows userspace to report long mode support via CPUID, even though
the guest is all but guaranteed to crash if it actually tries to enable
long mode.  But, a pure 32-bit guest that is ignorant of long mode will
happily plod along.

SMM complicates things as 64-bit CPUs use a different SMRAM save state
area.  KVM handles this correctly for 64-bit kernels, e.g. uses the
legacy save state map if userspace has hid long mode from the guest,
but doesn't fare well when userspace reports long mode support on a
32-bit host kernel (32-bit KVM doesn't support 64-bit guests).

Since the alternative is to crash the guest, e.g. by not loading state
or explicitly requesting shutdown, unconditionally use the legacy SMRAM
save state map for 32-bit KVM.  If a guest has managed to get far enough
to handle SMIs when running under a weird/buggy userspace hypervisor,
then don't deliberately crash the guest since there are no downsides
(from KVM's perspective) to allow it to continue running.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b68f3cc7
    • S
      KVM: x86: Don't clear EFER during SMM transitions for 32-bit vCPU · 8f4dc2e7
      由 Sean Christopherson 提交于 
      Neither AMD nor Intel CPUs have an EFER field in the legacy SMRAM save
state area, i.e. don't save/restore EFER across SMM transitions.  KVM
somewhat models this, e.g. doesn't clear EFER on entry to SMM if the
guest doesn't support long mode.  But during RSM, KVM unconditionally
clears EFER so that it can get back to pure 32-bit mode in order to
start loading CRs with their actual non-SMM values.

Clear EFER only when it will be written when loading the non-SMM state
so as to preserve bits that can theoretically be set on 32-bit vCPUs,
e.g. KVM always emulates EFER_SCE.

And because CR4.PAE is cleared only to play nice with EFER, wrap that
code in the long mode check as well.  Note, this may result in a
compiler warning about cr4 being consumed uninitialized.  Re-read CR4
even though it's technically unnecessary, as doing so allows for more
readable code and RSM emulation is not a performance critical path.

Fixes: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      8f4dc2e7
    • S
      KVM: x86: clear SMM flags before loading state while leaving SMM · 9ec19493
      由 Sean Christopherson 提交于 
      RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Stop dancing around the issue of HF_SMM_MASK being set when
loading SMSTATE into architectural state, e.g. by toggling it for
problematic flows, and simply clear HF_SMM_MASK prior to loading
architectural state (from SMRAM save state area).
Reported-by: NJon Doron <arilou@gmail.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 5bea5123 ("KVM: VMX: check nested state and CR4.VMXE against SMM")
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Tested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      9ec19493
    • S
      KVM: x86: Open code kvm_set_hflags · c5833c7a
      由 Sean Christopherson 提交于 
      Prepare for clearing HF_SMM_MASK prior to loading state from the SMRAM
save state map, i.e. kvm_smm_changed() needs to be called after state
has been loaded and so cannot be done automatically when setting
hflags from RSM.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      c5833c7a
    • S
      KVM: x86: Load SMRAM in a single shot when leaving SMM · ed19321f
      由 Sean Christopherson 提交于 
      RSM emulation is currently broken on VMX when the interrupted guest has
CR4.VMXE=1.  Rather than dance around the issue of HF_SMM_MASK being set
when loading SMSTATE into architectural state, ideally RSM emulation
itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM
architectural state.

Ostensibly, the only motivation for having HF_SMM_MASK set throughout
the loading of state from the SMRAM save state area is so that the
memory accesses from GET_SMSTATE() are tagged with role.smm.  Load
all of the SMRAM save state area from guest memory at the beginning of
RSM emulation, and load state from the buffer instead of reading guest
memory one-by-one.

This paves the way for clearing HF_SMM_MASK prior to loading state,
and also aligns RSM with the enter_smm() behavior, which fills a
buffer and writes SMRAM save state in a single go.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      ed19321f
  45. 06 1月, 2019 1 次提交
    • M
      jump_label: move 'asm goto' support test to Kconfig · e9666d10
      由 Masahiro Yamada 提交于 
      Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".

The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:

  #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
  # define HAVE_JUMP_LABEL
  #endif

We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.

Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: NSedat Dilek <sedat.dilek@gmail.com>
      e9666d10
  47. 29 10月, 2018 1 次提交
  49. 28 9月, 2018 1 次提交