diff options
| author | Gabriel L. Somlo <gsomlo@gmail.com> | 2014-05-07 16:52:13 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-05-08 15:40:49 +0200 |
| commit | 87c00572ba05aa8c9db118da75c608f47eb10b9e (patch) | |
| tree | 484e8cc1da97c7302c739364ee0af9bd68cebb0e /arch/x86/kvm/svm.c | |
| parent | b63cf42fd1d8c18fab71222321aaf356f63089c9 (diff) | |
kvm: x86: emulate monitor and mwait instructions as nop
Treat monitor and mwait instructions as nop, which is architecturally
correct (but inefficient) behavior. We do this to prevent misbehaving
guests (e.g. OS X <= 10.7) from crashing after they fail to check for
monitor/mwait availability via cpuid.
Since mwait-based idle loops relying on these nop-emulated instructions
would keep the host CPU pegged at 100%, do NOT advertise their presence
via cpuid, to prevent compliant guests from using them inadvertently.
Signed-off-by: Gabriel L. Somlo <somlo@cmu.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 7f4f9c2bada..0b7d58d0c5f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2770,12 +2770,6 @@ static int xsetbv_interception(struct vcpu_svm *svm) return 1; } -static int invalid_op_interception(struct vcpu_svm *svm) -{ - kvm_queue_exception(&svm->vcpu, UD_VECTOR); - return 1; -} - static int task_switch_interception(struct vcpu_svm *svm) { u16 tss_selector; @@ -3287,6 +3281,24 @@ static int pause_interception(struct vcpu_svm *svm) return 1; } +static int nop_interception(struct vcpu_svm *svm) +{ + skip_emulated_instruction(&(svm->vcpu)); + return 1; +} + +static int monitor_interception(struct vcpu_svm *svm) +{ + printk_once(KERN_WARNING "kvm: MONITOR instruction emulated as NOP!\n"); + return nop_interception(svm); +} + +static int mwait_interception(struct vcpu_svm *svm) +{ + printk_once(KERN_WARNING "kvm: MWAIT instruction emulated as NOP!\n"); + return nop_interception(svm); +} + static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = { [SVM_EXIT_READ_CR0] = cr_interception, [SVM_EXIT_READ_CR3] = cr_interception, @@ -3344,8 +3356,8 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = { [SVM_EXIT_CLGI] = clgi_interception, [SVM_EXIT_SKINIT] = skinit_interception, [SVM_EXIT_WBINVD] = emulate_on_interception, - [SVM_EXIT_MONITOR] = invalid_op_interception, - [SVM_EXIT_MWAIT] = invalid_op_interception, + [SVM_EXIT_MONITOR] = monitor_interception, + [SVM_EXIT_MWAIT] = mwait_interception, [SVM_EXIT_XSETBV] = xsetbv_interception, [SVM_EXIT_NPF] = pf_interception, }; |