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  1. 23 5月, 2018 4 次提交
    • J
      KVM: nVMX: Ensure that VMCS12 field offsets do not change · 21ebf53b
      由 Jim Mattson 提交于 
      Enforce the invariant that existing VMCS12 field offsets must not
change. Experience has shown that without strict enforcement, this
invariant will not be maintained.
Signed-off-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[Changed the code to use BUILD_BUG_ON_MSG instead of better, but GCC 4.6
 requiring _Static_assert. - Radim.]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      21ebf53b
    • J
      KVM: nVMX: Restore the VMCS12 offsets for v4.0 fields · b348e793
      由 Jim Mattson 提交于 
      Changing the VMCS12 layout will break save/restore compatibility with
older kvm releases once the KVM_{GET,SET}_NESTED_STATE ioctls are
accepted upstream. Google has already been using these ioctls for some
time, and we implore the community not to disturb the existing layout.

Move the four most recently added fields to preserve the offsets of
the previously defined fields and reserve locations for the vmread and
vmwrite bitmaps, which will be used in the virtualization of VMCS
shadowing (to improve the performance of double-nesting).
Signed-off-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[Kept the SDM order in vmcs_field_to_offset_table. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      b348e793
    • A
      KVM: x86: use timespec64 for KVM_HC_CLOCK_PAIRING · 899a31f5
      由 Arnd Bergmann 提交于 
      The hypercall was added using a struct timespec based implementation,
but we should not use timespec in new code.

This changes it to timespec64. There is no functional change
here since the implementation is only used in 64-bit kernels
that use the same definition for timespec and timespec64.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      899a31f5
    • J
      kvm: nVMX: Use nested_run_pending rather than from_vmentry · 6514dc38
      由 Jim Mattson 提交于 
      When saving a vCPU's nested state, the vmcs02 is discarded. Only the
shadow vmcs12 is saved. The shadow vmcs12 contains all of the
information needed to reconstruct an equivalent vmcs02 on restore, but
we have to be able to deal with two contexts:

1. The nested state was saved immediately after an emulated VM-entry,
   before the vmcs02 was ever launched.

2. The nested state was saved some time after the first successful
   launch of the vmcs02.

Though it's an implementation detail rather than an architected bit,
vmx->nested_run_pending serves to distinguish between these two
cases. Hence, we save it as part of the vCPU's nested state. (Yes,
this is ugly.)

Even when restoring from a checkpoint, it may be necessary to build
the vmcs02 as if prepare_vmcs02 was called from nested_vmx_run. So,
the 'from_vmentry' argument should be dropped, and
vmx->nested_run_pending should be consulted instead. The nested state
restoration code then has to set vmx->nested_run_pending prior to
calling prepare_vmcs02. It's important that the restoration code set
vmx->nested_run_pending anyway, since the flag impacts things like
interrupt delivery as well.

Fixes: cf8b84f4 ("kvm: nVMX: Prepare for checkpointing L2 state")
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      6514dc38
  3. 15 5月, 2018 8 次提交
  5. 11 5月, 2018 4 次提交
  7. 06 5月, 2018 1 次提交
    • A
      KVM: x86: remove APIC Timer periodic/oneshot spikes · ecf08dad
      由 Anthoine Bourgeois 提交于 
      Since the commit "8003c9ae: add APIC Timer periodic/oneshot mode VMX
preemption timer support", a Windows 10 guest has some erratic timer
spikes.

Here the results on a 150000 times 1ms timer without any load:
	  Before 8003c9ae | After 8003c9ae
Max           1834us          |  86000us
Mean          1100us          |   1021us
Deviation       59us          |    149us
Here the results on a 150000 times 1ms timer with a cpu-z stress test:
	  Before 8003c9ae | After 8003c9ae
Max          32000us          | 140000us
Mean          1006us          |   1997us
Deviation      140us          |  11095us

The root cause of the problem is starting hrtimer with an expiry time
already in the past can take more than 20 milliseconds to trigger the
timer function.  It can be solved by forward such past timers
immediately, rather than submitting them to hrtimer_start().
In case the timer is periodic, update the target expiration and call
hrtimer_start with it.

v2: Check if the tsc deadline is already expired. Thank you Mika.
v3: Execute the past timers immediately rather than submitting them to
hrtimer_start().
v4: Rearm the periodic timer with advance_periodic_target_expiration() a
simpler version of set_target_expiration(). Thank you Paolo.

Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NAnthoine Bourgeois <anthoine.bourgeois@blade-group.com>
8003c9ae ("KVM: LAPIC: add APIC Timer periodic/oneshot mode VMX preemption timer support")
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      ecf08dad
  9. 28 4月, 2018 1 次提交
  11. 27 4月, 2018 1 次提交
  13. 16 4月, 2018 2 次提交
  15. 13 4月, 2018 1 次提交
  17. 11 4月, 2018 2 次提交
  19. 10 4月, 2018 1 次提交
    • K
      X86/VMX: Disable VMX preemption timer if MWAIT is not intercepted · 386c6ddb
      由 KarimAllah Ahmed 提交于 
      The VMX-preemption timer is used by KVM as a way to set deadlines for the
guest (i.e. timer emulation). That was safe till very recently when
capability KVM_X86_DISABLE_EXITS_MWAIT to disable intercepting MWAIT was
introduced. According to Intel SDM 25.5.1:

"""
The VMX-preemption timer operates in the C-states C0, C1, and C2; it also
operates in the shutdown and wait-for-SIPI states. If the timer counts down
to zero in any state other than the wait-for SIPI state, the logical
processor transitions to the C0 C-state and causes a VM exit; the timer
does not cause a VM exit if it counts down to zero in the wait-for-SIPI
state. The timer is not decremented in C-states deeper than C2.
"""

Now once the guest issues the MWAIT with a c-state deeper than
C2 the preemption timer will never wake it up again since it stopped
ticking! Usually this is compensated by other activities in the system that
would wake the core from the deep C-state (and cause a VMExit). For
example, if the host itself is ticking or it received interrupts, etc!

So disable the VMX-preemption timer if MWAIT is exposed to the guest!

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: NKarimAllah Ahmed <karahmed@amazon.de>
Fixes: 4d5422ceSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      386c6ddb
  21. 07 4月, 2018 1 次提交
  23. 05 4月, 2018 7 次提交
    • P
      kvm: x86: fix a compile warning · 3140c156
      由 Peng Hao 提交于 
      fix a "warning: no previous prototype".

Cc: stable@vger.kernel.org
Signed-off-by: NPeng Hao <peng.hao2@zte.com.cn>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      3140c156
    • W
      KVM: X86: Add Force Emulation Prefix for "emulate the next instruction" · 6c86eedc
      由 Wanpeng Li 提交于 
      There is no easy way to force KVM to run an instruction through the emulator
(by design as that will expose the x86 emulator as a significant attack-surface).
However, we do wish to expose the x86 emulator in case we are testing it
(e.g. via kvm-unit-tests). Therefore, this patch adds a "force emulation prefix"
that is designed to raise #UD which KVM will trap and it's #UD exit-handler will
match "force emulation prefix" to run instruction after prefix by the x86 emulator.
To not expose the x86 emulator by default, we add a module parameter that should
be off by default.

A simple testcase here:

    #include <stdio.h>
    #include <string.h>

    #define HYPERVISOR_INFO 0x40000000

    #define CPUID(idx, eax, ebx, ecx, edx) \
        asm volatile (\
        "ud2a; .ascii \"kvm\"; cpuid" \
        :"=b" (*ebx), "=a" (*eax), "=c" (*ecx), "=d" (*edx) \
            :"0"(idx) );

    void main()
    {
        unsigned int eax, ebx, ecx, edx;
        char string[13];

        CPUID(HYPERVISOR_INFO, &eax, &ebx, &ecx, &edx);
        *(unsigned int *)(string + 0) = ebx;
        *(unsigned int *)(string + 4) = ecx;
        *(unsigned int *)(string + 8) = edx;

        string[12] = 0;
        if (strncmp(string, "KVMKVMKVM\0\0\0", 12) == 0)
            printf("kvm guest\n");
        else
            printf("bare hardware\n");
    }
Suggested-by: NAndrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NLiran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
[Correctly handle usermode exits. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6c86eedc
    • W
      KVM: X86: Introduce handle_ud() · 082d06ed
      由 Wanpeng Li 提交于 
      Introduce handle_ud() to handle invalid opcode, this function will be
used by later patches.
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NLiran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      082d06ed
    • P
      KVM: vmx: unify adjacent #ifdefs · 4fde8d57
      由 Paolo Bonzini 提交于 
      vmx_save_host_state has multiple ifdefs for CONFIG_X86_64 that have
no other code between them.  Simplify by reducing them to a single
conditional.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      4fde8d57
    • A
      x86: kvm: hide the unused 'cpu' variable · 51e8a8cc
      由 Arnd Bergmann 提交于 
      The local variable was newly introduced but is only accessed in one
place on x86_64, but not on 32-bit:

arch/x86/kvm/vmx.c: In function 'vmx_save_host_state':
arch/x86/kvm/vmx.c:2175:6: error: unused variable 'cpu' [-Werror=unused-variable]

This puts it into another #ifdef.

Fixes: 35060ed6 ("x86/kvm/vmx: avoid expensive rdmsr for MSR_GS_BASE")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      51e8a8cc
    • S
      KVM: VMX: remove bogus WARN_ON in handle_ept_misconfig · c75d0edc
      由 Sean Christopherson 提交于 
      Remove the WARN_ON in handle_ept_misconfig() as it is unnecessary
and causes false positives.  Return the unmodified result of
kvm_mmu_page_fault() instead of converting a system error code to
KVM_EXIT_UNKNOWN so that userspace sees the error code of the
actual failure, not a generic "we don't know what went wrong".

  * kvm_mmu_page_fault() will WARN if reserved bits are set in the
    SPTEs, i.e. it covers the case where an EPT misconfig occurred
    because of a KVM bug.

  * The WARN_ON will fire on any system error code that is hit while
    handling the fault, e.g. -ENOMEM from mmu_topup_memory_caches()
    while handling a legitmate MMIO EPT misconfig or -EFAULT from
    kvm_handle_bad_page() if the corresponding HVA is invalid.  In
    either case, userspace should receive the original error code
    and firing a warning is incorrect behavior as KVM is operating
    as designed.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      c75d0edc
    • S
      Revert "KVM: X86: Fix SMRAM accessing even if VM is shutdown" · 2c151b25
      由 Sean Christopherson 提交于 
      The bug that led to commit 95e057e2
was a benign warning (no adverse affects other than the warning
itself) that was detected by syzkaller.  Further inspection shows
that the WARN_ON in question, in handle_ept_misconfig(), is
unnecessary and flawed (this was also briefly discussed in the
original patch: https://patchwork.kernel.org/patch/10204649).

  * The WARN_ON is unnecessary as kvm_mmu_page_fault() will WARN
    if reserved bits are set in the SPTEs, i.e. it covers the case
    where an EPT misconfig occurred because of a KVM bug.

  * The WARN_ON is flawed because it will fire on any system error
    code that is hit while handling the fault, e.g. -ENOMEM can be
    returned by mmu_topup_memory_caches() while handling a legitmate
    MMIO EPT misconfig.

The original behavior of returning -EFAULT when userspace munmaps
an HVA without first removing the memslot is correct and desirable,
i.e. KVM is letting userspace know it has generated a bad address.
Returning RET_PF_EMULATE masks the WARN_ON in the EPT misconfig path,
but does not fix the underlying bug, i.e. the WARN_ON is bogus.

Furthermore, returning RET_PF_EMULATE has the unwanted side effect of
causing KVM to attempt to emulate an instruction on any page fault
with an invalid HVA translation, e.g. a not-present EPT violation
on a VM_PFNMAP VMA whose fault handler failed to insert a PFN.

  * There is no guarantee that the fault is directly related to the
    instruction, i.e. the fault could have been triggered by a side
    effect memory access in the guest, e.g. while vectoring a #DB or
    writing a tracing record.  This could cause KVM to effectively
    mask the fault if KVM doesn't model the behavior leading to the
    fault, i.e. emulation could succeed and resume the guest.

  * If emulation does fail, KVM will return EMULATION_FAILED instead
    of -EFAULT, which is a red herring as the user will either debug
    a bogus emulation attempt or scratch their head wondering why we
    were attempting emulation in the first place.

TL;DR: revert to returning -EFAULT and remove the bogus WARN_ON in
handle_ept_misconfig in a future patch.

This reverts commit 95e057e2.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      2c151b25
  25. 04 4月, 2018 2 次提交
    • S
      kvm: Add emulation for movups/movupd · 29916968
      由 Stefan Fritsch 提交于 
      This is very similar to the aligned versions movaps/movapd.

We have seen the corresponding emulation failures with openbsd as guest
and with Windows 10 with intel HD graphics pass through.
Signed-off-by: NChristian Ehrhardt <christian_ehrhardt@genua.de>
Signed-off-by: NStefan Fritsch <sf@sfritsch.de>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      29916968
    • S
      KVM: VMX: raise internal error for exception during invalid protected mode state · add5ff7a
      由 Sean Christopherson 提交于 
      Exit to userspace with KVM_INTERNAL_ERROR_EMULATION if we encounter
an exception in Protected Mode while emulating guest due to invalid
guest state.  Unlike Big RM, KVM doesn't support emulating exceptions
in PM, i.e. PM exceptions are always injected via the VMCS.  Because
we will never do VMRESUME due to emulation_required, the exception is
never realized and we'll keep emulating the faulting instruction over
and over until we receive a signal.

Exit to userspace iff there is a pending exception, i.e. don't exit
simply on a requested event. The purpose of this check and exit is to
aid in debugging a guest that is in all likelihood already doomed.
Invalid guest state in PM is extremely limited in normal operation,
e.g. it generally only occurs for a few instructions early in BIOS,
and any exception at this time is all but guaranteed to be fatal.
Non-vectored interrupts, e.g. INIT, SIPI and SMI, can be cleanly
handled/emulated, while checking for vectored interrupts, e.g. INTR
and NMI, without hitting false positives would add a fair amount of
complexity for almost no benefit (getting hit by lightning seems
more likely than encountering this specific scenario).

Add a WARN_ON_ONCE to vmx_queue_exception() if we try to inject an
exception via the VMCS and emulation_required is true.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      add5ff7a
  27. 29 3月, 2018 5 次提交
    • L
      KVM: nVMX: Optimization: Dont set KVM_REQ_EVENT when VMExit with nested_run_pending · f497b6c2
      由 Liran Alon 提交于 
      When vCPU runs L2 and there is a pending event that requires to exit
from L2 to L1 and nested_run_pending=1, vcpu_enter_guest() will request
an immediate-exit from L2 (See req_immediate_exit).

Since now handling of req_immediate_exit also makes sure to set
KVM_REQ_EVENT, there is no need to also set it on vmx_vcpu_run() when
nested_run_pending=1.

This optimizes cases where VMRESUME was executed by L1 to enter L2 and
there is no pending events that require exit from L2 to L1. Previously,
this would have set KVM_REQ_EVENT unnecessarly.
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      f497b6c2
    • L
      KVM: nVMX: Require immediate-exit when event reinjected to L2 and L1 event pending · 1a680e35
      由 Liran Alon 提交于 
      In case L2 VMExit to L0 during event-delivery, VMCS02 is filled with
IDT-vectoring-info which vmx_complete_interrupts() makes sure to
reinject before next resume of L2.

While handling the VMExit in L0, an IPI could be sent by another L1 vCPU
to the L1 vCPU which currently runs L2 and exited to L0.

When L0 will reach vcpu_enter_guest() and call inject_pending_event(),
it will note that a previous event was re-injected to L2 (by
IDT-vectoring-info) and therefore won't check if there are pending L1
events which require exit from L2 to L1. Thus, L0 enters L2 without
immediate VMExit even though there are pending L1 events!

This commit fixes the issue by making sure to check for L1 pending
events even if a previous event was reinjected to L2 and bailing out
from inject_pending_event() before evaluating a new pending event in
case an event was already reinjected.

The bug was observed by the following setup:
* L0 is a 64CPU machine which runs KVM.
* L1 is a 16CPU machine which runs KVM.
* L0 & L1 runs with APICv disabled.
(Also reproduced with APICv enabled but easier to analyze below info
with APICv disabled)
* L1 runs a 16CPU L2 Windows Server 2012 R2 guest.
During L2 boot, L1 hangs completely and analyzing the hang reveals that
one L1 vCPU is holding KVM's mmu_lock and is waiting forever on an IPI
that he has sent for another L1 vCPU. And all other L1 vCPUs are
currently attempting to grab mmu_lock. Therefore, all L1 vCPUs are stuck
forever (as L1 runs with kernel-preemption disabled).

Observing /sys/kernel/debug/tracing/trace_pipe reveals the following
series of events:
(1) qemu-system-x86-19066 [030] kvm_nested_vmexit: rip:
0xfffff802c5dca82f reason: EPT_VIOLATION ext_inf1: 0x0000000000000182
ext_inf2: 0x00000000800000d2 ext_int: 0x00000000 ext_int_err: 0x00000000
(2) qemu-system-x86-19054 [028] kvm_apic_accept_irq: apicid f
vec 252 (Fixed|edge)
(3) qemu-system-x86-19066 [030] kvm_inj_virq: irq 210
(4) qemu-system-x86-19066 [030] kvm_entry: vcpu 15
(5) qemu-system-x86-19066 [030] kvm_exit: reason EPT_VIOLATION
rip 0xffffe00069202690 info 83 0
(6) qemu-system-x86-19066 [030] kvm_nested_vmexit: rip:
0xffffe00069202690 reason: EPT_VIOLATION ext_inf1: 0x0000000000000083
ext_inf2: 0x0000000000000000 ext_int: 0x00000000 ext_int_err: 0x00000000
(7) qemu-system-x86-19066 [030] kvm_nested_vmexit_inject: reason:
EPT_VIOLATION ext_inf1: 0x0000000000000083 ext_inf2: 0x0000000000000000
ext_int: 0x00000000 ext_int_err: 0x00000000
(8) qemu-system-x86-19066 [030] kvm_entry: vcpu 15

Which can be analyzed as follows:
(1) L2 VMExit to L0 on EPT_VIOLATION during delivery of vector 0xd2.
Therefore, vmx_complete_interrupts() will set KVM_REQ_EVENT and reinject
a pending-interrupt of 0xd2.
(2) L1 sends an IPI of vector 0xfc (CALL_FUNCTION_VECTOR) to destination
vCPU 15. This will set relevant bit in LAPIC's IRR and set KVM_REQ_EVENT.
(3) L0 reach vcpu_enter_guest() which calls inject_pending_event() which
notes that interrupt 0xd2 was reinjected and therefore calls
vmx_inject_irq() and returns. Without checking for pending L1 events!
Note that at this point, KVM_REQ_EVENT was cleared by vcpu_enter_guest()
before calling inject_pending_event().
(4) L0 resumes L2 without immediate-exit even though there is a pending
L1 event (The IPI pending in LAPIC's IRR).

We have already reached the buggy scenario but events could be
furthered analyzed:
(5+6) L2 VMExit to L0 on EPT_VIOLATION.  This time not during
event-delivery.
(7) L0 decides to forward the VMExit to L1 for further handling.
(8) L0 resumes into L1. Note that because KVM_REQ_EVENT is cleared, the
LAPIC's IRR is not examined and therefore the IPI is still not delivered
into L1!
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      1a680e35
    • L
      KVM: x86: Fix misleading comments on handling pending exceptions · a042c26f
      由 Liran Alon 提交于 
      The reason that exception.pending should block re-injection of
NMI/interrupt is not described correctly in comment in code.
Instead, it describes why a pending exception should be injected
before a pending NMI/interrupt.

Therefore, move currently present comment to code-block evaluating
a new pending event which explains why exception.pending is evaluated
first.
In addition, create a new comment describing that exception.pending
blocks re-injection of NMI/interrupt because the exception was
queued by handling vmexit which was due to NMI/interrupt delivery.
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@orcle.com>
[Used a comment from Sean J <sean.j.christopherson@intel.com>. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      a042c26f
    • L
      KVM: x86: Rename interrupt.pending to interrupt.injected · 04140b41
      由 Liran Alon 提交于 
      For exceptions & NMIs events, KVM code use the following
coding convention:
*) "pending" represents an event that should be injected to guest at
some point but it's side-effects have not yet occurred.
*) "injected" represents an event that it's side-effects have already
occurred.

However, interrupts don't conform to this coding convention.
All current code flows mark interrupt.pending when it's side-effects
have already taken place (For example, bit moved from LAPIC IRR to
ISR). Therefore, it makes sense to just rename
interrupt.pending to interrupt.injected.

This change follows logic of previous commit 664f8e26 ("KVM: X86:
Fix loss of exception which has not yet been injected") which changed
exception to follow this coding convention as well.

It is important to note that in case !lapic_in_kernel(vcpu),
interrupt.pending usage was and still incorrect.
In this case, interrrupt.pending can only be set using one of the
following ioctls: KVM_INTERRUPT, KVM_SET_VCPU_EVENTS and
KVM_SET_SREGS. Looking at how QEMU uses these ioctls, one can see that
QEMU uses them either to re-set an "interrupt.pending" state it has
received from KVM (via KVM_GET_VCPU_EVENTS interrupt.pending or
via KVM_GET_SREGS interrupt_bitmap) or by dispatching a new interrupt
from QEMU's emulated LAPIC which reset bit in IRR and set bit in ISR
before sending ioctl to KVM. So it seems that indeed "interrupt.pending"
in this case is also suppose to represent "interrupt.injected".
However, kvm_cpu_has_interrupt() & kvm_cpu_has_injectable_intr()
is misusing (now named) interrupt.injected in order to return if
there is a pending interrupt.
This leads to nVMX/nSVM not be able to distinguish if it should exit
from L2 to L1 on EXTERNAL_INTERRUPT on pending interrupt or should
re-inject an injected interrupt.
Therefore, add a FIXME at these functions for handling this issue.

This patch introduce no semantics change.
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      04140b41
    • L
      KVM: VMX: No need to clear pending NMI/interrupt on inject realmode interrupt · 7c5a6a59
      由 Liran Alon 提交于 
      kvm_inject_realmode_interrupt() is called from one of the injection
functions which writes event-injection to VMCS: vmx_queue_exception(),
vmx_inject_irq() and vmx_inject_nmi().

All these functions are called just to cause an event-injection to
guest. They are not responsible of manipulating the event-pending
flag. The only purpose of kvm_inject_realmode_interrupt() should be
to emulate real-mode interrupt-injection.

This was also incorrect when called from vmx_queue_exception().
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      7c5a6a59