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>
This commit is contained in:
parent
c2ce3f5d89
commit
f244deed7a
|
@ -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)
|
||||
{
|
||||
|
|
Loading…
Reference in New Issue