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| author | Gleb Natapov <gleb@redhat.com> | 2009-03-30 16:03:29 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2009-06-10 11:48:38 +0300 |
| commit | 64a7ec066813443440bfc9f60a9e76a47cfa6b2b (patch) | |
| tree | d6d3461ba7667ac2801350d5b3b518e84b5df0f6 /arch/x86/kvm/vmx.c | |
| parent | b237ac37a149e8b56436fabf093532483bff13b0 (diff) | |
| download | lwn-64a7ec066813443440bfc9f60a9e76a47cfa6b2b.tar.gz lwn-64a7ec066813443440bfc9f60a9e76a47cfa6b2b.zip | |
KVM: Fix unneeded instruction skipping during task switching.
There is no need to skip instruction if the reason for a task switch
is a task gate in IDT and access to it is caused by an external even.
The problem is currently solved only for VMX since there is no reliable
way to skip an instruction in SVM. We should emulate it instead.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e4ad9d3c0636..c6997c0e8ca6 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3038,22 +3038,40 @@ static int handle_task_switch(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) struct vcpu_vmx *vmx = to_vmx(vcpu); unsigned long exit_qualification; u16 tss_selector; - int reason; + int reason, type, idt_v; + + idt_v = (vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK); + type = (vmx->idt_vectoring_info & VECTORING_INFO_TYPE_MASK); exit_qualification = vmcs_readl(EXIT_QUALIFICATION); reason = (u32)exit_qualification >> 30; - if (reason == TASK_SWITCH_GATE && vmx->vcpu.arch.nmi_injected && - (vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK) && - (vmx->idt_vectoring_info & VECTORING_INFO_TYPE_MASK) - == INTR_TYPE_NMI_INTR) { - vcpu->arch.nmi_injected = false; - if (cpu_has_virtual_nmis()) - vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, - GUEST_INTR_STATE_NMI); + if (reason == TASK_SWITCH_GATE && idt_v) { + switch (type) { + case INTR_TYPE_NMI_INTR: + vcpu->arch.nmi_injected = false; + if (cpu_has_virtual_nmis()) + vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, + GUEST_INTR_STATE_NMI); + break; + case INTR_TYPE_EXT_INTR: + kvm_clear_interrupt_queue(vcpu); + break; + case INTR_TYPE_HARD_EXCEPTION: + case INTR_TYPE_SOFT_EXCEPTION: + kvm_clear_exception_queue(vcpu); + break; + default: + break; + } } tss_selector = exit_qualification; + if (!idt_v || (type != INTR_TYPE_HARD_EXCEPTION && + type != INTR_TYPE_EXT_INTR && + type != INTR_TYPE_NMI_INTR)) + skip_emulated_instruction(vcpu); + if (!kvm_task_switch(vcpu, tss_selector, reason)) return 0; @@ -3306,7 +3324,7 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx) vector = idt_vectoring_info & VECTORING_INFO_VECTOR_MASK; type = idt_vectoring_info & VECTORING_INFO_TYPE_MASK; - switch(type) { + switch (type) { case INTR_TYPE_NMI_INTR: vmx->vcpu.arch.nmi_injected = true; /* |