[PATCH] svm: exit to userspace if write to cr8 and not using in-kernel apic

["Joerg Roedel" <joerg.roedel-5C7GfCeVMHo@public.gmane.org>]

With this patch KVM on SVM will exit to userspace if the guest writes to CR8
and the in-kernel APIC is disabled.

Signed-off-by: Joerg Roedel <joerg.roedel-5C7GfCeVMHo@public.gmane.org>
Signed-off-by: Markus Rechberger <markus.rechberger-5C7GfCeVMHo@public.gmane.org>
---
 drivers/kvm/svm.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 677b525..9f8564a 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1048,6 +1048,15 @@ static int emulate_on_interception(struct vcpu_svm *svm,
 	return 1;
 }
 
+static int cr8_write_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+	emulate_instruction(&svm->vcpu, NULL, 0, 0, 0);
+	if (irqchip_in_kernel(svm->vcpu.kvm))
+		return 1;
+	kvm_run->exit_reason = KVM_EXIT_SET_TPR;
+	return 0;
+}
+
 static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -1202,7 +1211,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
 	[SVM_EXIT_WRITE_CR0]          		= emulate_on_interception,
 	[SVM_EXIT_WRITE_CR3]          		= emulate_on_interception,
 	[SVM_EXIT_WRITE_CR4]          		= emulate_on_interception,
-	[SVM_EXIT_WRITE_CR8]          		= emulate_on_interception,
+	[SVM_EXIT_WRITE_CR8]          		= cr8_write_interception,
 	[SVM_EXIT_READ_DR0] 			= emulate_on_interception,
 	[SVM_EXIT_READ_DR1]			= emulate_on_interception,
 	[SVM_EXIT_READ_DR2]			= emulate_on_interception,
-- 
1.5.2.5




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