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KVM: x86: Handle emulation failure directly in kvm_task_switch()

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Consolidate the reporting of emulation failure into kvm_task_switch()
so that it can return EMULATE_USER_EXIT.  This helps pave the way for
removing EMULATE_FAIL altogether.

This also fixes a theoretical bug where task switch interception could
suppress an EMULATE_USER_EXIT return.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2019-08-27 14:40:35 -07:00 committed by Paolo Bonzini
parent 738fece46d
commit 1051778f6e
3 changed files with 11 additions and 23 deletions
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11
arch/x86/kvm/svm.c
View File

@ -3892,17 +3892,10 @@ static int task_switch_interception(struct vcpu_svm *svm)
if (int_type != SVM_EXITINTINFO_TYPE_SOFT)
int_vec = -1;
if (kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
has_error_code, error_code) == EMULATE_FAIL)
goto fail;
return 1;
fail:
svm->vcpu.run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
svm->vcpu.run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
svm->vcpu.run->internal.ndata = 0;
return 0;
return kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
has_error_code, error_code) != EMULATE_USER_EXIT;
}
static int cpuid_interception(struct vcpu_svm *svm)

14
arch/x86/kvm/vmx/vmx.c
View File

@ -5074,21 +5074,13 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
type != INTR_TYPE_NMI_INTR))
skip_emulated_instruction(vcpu);
if (kvm_task_switch(vcpu, tss_selector,
type == INTR_TYPE_SOFT_INTR ? idt_index : -1, reason,
has_error_code, error_code) == EMULATE_FAIL) {
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
vcpu->run->internal.ndata = 0;
return 0;
}
/*
* TODO: What about debug traps on tss switch?
* Are we supposed to inject them and update dr6?
*/
return 1;
return kvm_task_switch(vcpu, tss_selector,
type == INTR_TYPE_SOFT_INTR ? idt_index : -1,
reason, has_error_code, error_code) != EMULATE_USER_EXIT;
}
static int handle_ept_violation(struct kvm_vcpu *vcpu)

9
arch/x86/kvm/x86.c
View File

@ -8693,9 +8693,12 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason,
has_error_code, error_code);
if (ret)
return EMULATE_FAIL;
if (ret) {
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
vcpu->run->internal.ndata = 0;
return EMULATE_USER_EXIT;
}
kvm_rip_write(vcpu, ctxt->eip);
kvm_set_rflags(vcpu, ctxt->eflags);