[1/2] use explicit 64bit storage for sysenter values

Commit Message

Andre Przywara May 28, 2009, 9:56 a.m. UTC

Since AMD does not support sysenter in 64bit mode, the VMCB fields storing
the MSRs are truncated to 32bit upon VMRUN/#VMEXIT. So store the values
in a separate 64bit storage to avoid truncation.

Signed-off-by: Christoph Egger <[e-mail]>
---
 arch/x86/kvm/kvm_svm.h |    4 ++++
 arch/x86/kvm/svm.c     |   12 ++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

Comments

Avi Kivity May 31, 2009, 8:53 a.m. UTC | #1

Andre Przywara wrote:
> Since AMD does not support sysenter in 64bit mode, the VMCB fields storing
> the MSRs are truncated to 32bit upon VMRUN/#VMEXIT. So store the values
> in a separate 64bit storage to avoid truncation.
>   

Applied, thanks.

> +	struct kvm_segment user_cs; /* used in sysenter/sysexit emulation */
>   

Dropped this, unused.

Patch

diff --git a/arch/x86/kvm/kvm_svm.h b/arch/x86/kvm/kvm_svm.h
index ed66e4c..4129dc1 100644
--- a/arch/x86/kvm/kvm_svm.h
+++ b/arch/x86/kvm/kvm_svm.h
@@ -27,6 +27,10 @@  struct vcpu_svm {
 	unsigned long vmcb_pa;
 	struct svm_cpu_data *svm_data;
 	uint64_t asid_generation;
+	uint64_t sysenter_cs;
+	uint64_t sysenter_esp;
+	uint64_t sysenter_eip;
+	struct kvm_segment user_cs; /* used in sysenter/sysexit emulation */
 
 	u64 next_rip;
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index dd667dd..f0f2885 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1978,13 +1978,13 @@  static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
 		break;
 #endif
 	case MSR_IA32_SYSENTER_CS:
-		*data = svm->vmcb->save.sysenter_cs;
+		*data = svm->sysenter_cs;
 		break;
 	case MSR_IA32_SYSENTER_EIP:
-		*data = svm->vmcb->save.sysenter_eip;
+		*data = svm->sysenter_eip;
 		break;
 	case MSR_IA32_SYSENTER_ESP:
-		*data = svm->vmcb->save.sysenter_esp;
+		*data = svm->sysenter_esp;
 		break;
 	/* Nobody will change the following 5 values in the VMCB so
 	   we can safely return them on rdmsr. They will always be 0
@@ -2068,13 +2068,13 @@  static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 		break;
 #endif
 	case MSR_IA32_SYSENTER_CS:
-		svm->vmcb->save.sysenter_cs = data;
+		svm->sysenter_cs = data;
 		break;
 	case MSR_IA32_SYSENTER_EIP:
-		svm->vmcb->save.sysenter_eip = data;
+		svm->sysenter_eip = data;
 		break;
 	case MSR_IA32_SYSENTER_ESP:
-		svm->vmcb->save.sysenter_esp = data;
+		svm->sysenter_esp = data;
 		break;
 	case MSR_IA32_DEBUGCTLMSR:
 		if (!svm_has(SVM_FEATURE_LBRV)) {