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| author |   Wanpeng Li <wanpeng.li@hotmail.com> | 2017-07-20 01:11:54 -0700 |
|---|---|---|
| committer |   Radim Krčmář <rkrcmar@redhat.com> | 2017-07-20 17:00:00 +0200 |
| commit | f244deed7a254b4a61333e6886575ce0102e8356 (patch) | |
| tree | da8046fc368f57164a8816340465955b5673f3fb /arch | |
| parent | x86: add MULTIUSER dependency for KVM (diff) | |
| download | linux-dev-f244deed7a254b4a61333e6886575ce0102e8356.tar.xz linux-dev-f244deed7a254b4a61333e6886575ce0102e8356.zip | |
KVM: VMX: Fix invalid guest state detection after task-switch emulation
This can be reproduced by EPT=1, unrestricted_guest=N, emulate_invalid_state=Y
or EPT=0, the trace of kvm-unit-tests/taskswitch2.flat is like below, it tries
to emulate invalid guest state task-switch:
kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0
kvm_emulate_insn: 42000:0:0f 0b (0x2)
kvm_emulate_insn: 42000:0:0f 0b (0x2) failed
kvm_inj_exception: #UD (0x0)
kvm_entry: vcpu 0
kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0
kvm_emulate_insn: 42000:0:0f 0b (0x2)
kvm_emulate_insn: 42000:0:0f 0b (0x2) failed
kvm_inj_exception: #UD (0x0)
......................
It appears that the task-switch emulation updates rflags (and vm86
flag) only after the segments are loaded, causing vmx->emulation_required
to be set, when in fact invalid guest state emulation is not needed.
This patch fixes it by updating vmx->emulation_required after the
rflags (and vm86 flag) is updated in task-switch emulation.
Thanks Radim for moving the update to vmx__set_flags and adding Paolo's
suggestion for the check.
Suggested-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 791c018a0034..29fd8af5c347 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2327,6 +2327,11 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu) __vmx_load_host_state(to_vmx(vcpu)); } +static bool emulation_required(struct kvm_vcpu *vcpu) +{ + return emulate_invalid_guest_state && !guest_state_valid(vcpu); +} + static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu); /* @@ -2364,6 +2369,8 @@ static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu) static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) { + unsigned long old_rflags = vmx_get_rflags(vcpu); + __set_bit(VCPU_EXREG_RFLAGS, (ulong *)&vcpu->arch.regs_avail); to_vmx(vcpu)->rflags = rflags; if (to_vmx(vcpu)->rmode.vm86_active) { @@ -2371,6 +2378,9 @@ static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags) rflags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM; } vmcs_writel(GUEST_RFLAGS, rflags); + + if ((old_rflags ^ to_vmx(vcpu)->rflags) & X86_EFLAGS_VM) + to_vmx(vcpu)->emulation_required = emulation_required(vcpu); } static u32 vmx_get_pkru(struct kvm_vcpu *vcpu) @@ -3858,11 +3868,6 @@ static __init int alloc_kvm_area(void) return 0; } -static bool emulation_required(struct kvm_vcpu *vcpu) -{ - return emulate_invalid_guest_state && !guest_state_valid(vcpu); -} - static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg, struct kvm_segment *save) { |