KVM: prevent spurious exit to userspace during task switch emulation.
If kvm_task_switch() fails code exits to userspace without specifying
exit reason, so the previous exit reason is reused by userspace. Fix
this by specifying exit reason correctly.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 78af522..ab78eb8 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2266,8 +2266,14 @@
(int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
skip_emulated_instruction(&svm->vcpu);
- return kvm_task_switch(&svm->vcpu, tss_selector, reason,
- has_error_code, error_code);
+ if (kvm_task_switch(&svm->vcpu, tss_selector, reason,
+ has_error_code, error_code) == EMULATE_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 1;
}
static int cpuid_interception(struct vcpu_svm *svm)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1b38d8a..6e5e75e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3316,9 +3316,13 @@
type != INTR_TYPE_NMI_INTR))
skip_emulated_instruction(vcpu);
- if (!kvm_task_switch(vcpu, tss_selector, reason, has_error_code,
- error_code))
+ if (kvm_task_switch(vcpu, tss_selector, 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;
+ }
/* clear all local breakpoint enable flags */
vmcs_writel(GUEST_DR7, vmcs_readl(GUEST_DR7) & ~55);