KVM: x86 emulator: Allow PM/VM86 switch during task switch
Task switches can switch between Protected Mode and VM86. The current
mode must be updated during the task switch emulation so that the new
segment selectors are interpreted correctly.
In order to let privilege checks succeed, rflags needs to be updated in
the vcpu struct as this causes a CPL update.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ab39d84..53efd59 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1354,7 +1354,11 @@
static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
+ unsigned long old_rflags = to_svm(vcpu)->vmcb->save.rflags;
+
to_svm(vcpu)->vmcb->save.rflags = rflags;
+ if ((old_rflags ^ rflags) & X86_EFLAGS_VM)
+ svm_update_cpl(vcpu);
}
static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)