Fix sysenter migration issue on AMD CPUs

Commit Message

Andre Przywara Aug. 24, 2009, 1:03 p.m. UTC

Thomas Besser wrote:
> Andre Przywara wrote:
>> Stephane, Thomas: Can you verify this?
> 
> I'm not very familiar with compiling kvm-mod from git sources. And your
> patch does not apply to svm.c shipped with kernel 2.6.30.5
You shouldn't have seen any problems with 2.6.30.5, since the code in 
question (sysenter/syscall emulation) is not in here.

> 
> So at the moment I have no clue, how to verify. Is there any short howto out
> there, how to get kvm module from git source?
You can use the attached patch, which applies against 
kvm-kmod-devel-88.tar.gz

If that does not help, tell me with what tree or tarball you are usually 
generating the KVM kernel modules. I use Avi's latest git tree, which is 
regularly synced with 2.6.31.rc<x>. The patch from Friday should apply 
against this one.
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm.git
You will have to build your whole kernel with this tree, if you build 
only the modules from here they will certainly mismatch your running kernel.

Regards,
Andre.

Comments

Thomas Besser Aug. 24, 2009, 2:06 p.m. UTC | #1

Andre Przywara wrote:

> Thomas Besser wrote:
>> Andre Przywara wrote:
>>> Stephane, Thomas: Can you verify this?
>> 
>> I'm not very familiar with compiling kvm-mod from git sources. And your
>> patch does not apply to svm.c shipped with kernel 2.6.30.5
> You shouldn't have seen any problems with 2.6.30.5, since the code in
> question (sysenter/syscall emulation) is not in here.

Both hosts running 2.6.30.5 with kvm as module from kernel source. So I
should have another problem with live migration and qemu-kvm (0.10.6). 

Probably this http://article.gmane.org/gmane.comp.emulators.kvm.devel/39185

Thanx
Thomas

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Patch

diff --git a/x86/svm.c b/x86/svm.c
index fb29061..75d18bf 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -117,7 +117,6 @@  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;
 
@@ -436,8 +435,6 @@  static void svm_vcpu_init_msrpm(u32 *msrpm)
 #endif
 	set_msr_interception(msrpm, MSR_K6_STAR, 1, 1);
 	set_msr_interception(msrpm, MSR_IA32_SYSENTER_CS, 1, 1);
-	set_msr_interception(msrpm, MSR_IA32_SYSENTER_ESP, 1, 1);
-	set_msr_interception(msrpm, MSR_IA32_SYSENTER_EIP, 1, 1);
 }
 
 static void svm_enable_lbrv(struct vcpu_svm *svm)
@@ -2062,7 +2059,7 @@  static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
 		break;
 #endif
 	case MSR_IA32_SYSENTER_CS:
-		*data = svm->sysenter_cs;
+		*data = svm->vmcb->save.sysenter_cs;
 		break;
 	case MSR_IA32_SYSENTER_EIP:
 		*data = svm->sysenter_eip;
@@ -2151,13 +2148,15 @@  static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 		break;
 #endif
 	case MSR_IA32_SYSENTER_CS:
-		svm->sysenter_cs = data;
+		svm->vmcb->save.sysenter_cs = data;
 		break;
 	case MSR_IA32_SYSENTER_EIP:
 		svm->sysenter_eip = data;
+		svm->vmcb->save.sysenter_eip = data;
 		break;
 	case MSR_IA32_SYSENTER_ESP:
 		svm->sysenter_esp = data;
+		svm->vmcb->save.sysenter_esp = data;
 		break;
 	case MSR_IA32_DEBUGCTLMSR:
 		if (!svm_has(SVM_FEATURE_LBRV)) {