commit 74545705cb2e398efc3cd751628c58f021323434
author Radim Krčmář <rkrcmar@redhat.com> Mon Apr 27 15:11:25 2015 +0200
committer Paolo Bonzini <pbonzini@redhat.com> Thu May 07 11:29:46 2015 +0200
tree e9f946816e8cb963678db7fa5e9e0471b3590792
parent 653f52c316a49c5ee2701bc13b15879f20790662

KVM: x86: fix initial PAT value

PAT should be 0007_0406_0007_0406h on RESET and not modified on INIT.
VMX used a wrong value (host's PAT) and while SVM used the right one,
it never got to arch.pat.

This is not an issue with QEMU as it will force the correct value.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b6ad0f9..8954d7a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1176,7 +1176,7 @@
 		clr_exception_intercept(svm, PF_VECTOR);
 		clr_cr_intercept(svm, INTERCEPT_CR3_READ);
 		clr_cr_intercept(svm, INTERCEPT_CR3_WRITE);
-		save->g_pat = 0x0007040600070406ULL;
+		save->g_pat = svm->vcpu.arch.pat;
 		save->cr3 = 0;
 		save->cr4 = 0;
 	}

arch/x86/kvm/vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a694ff6..3c218fd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4667,16 +4667,8 @@
 	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0);
 	vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest));
 
-	if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
-		u32 msr_low, msr_high;
-		u64 host_pat;
-		rdmsr(MSR_IA32_CR_PAT, msr_low, msr_high);
-		host_pat = msr_low | ((u64) msr_high << 32);
-		/* Write the default value follow host pat */
-		vmcs_write64(GUEST_IA32_PAT, host_pat);
-		/* Keep arch.pat sync with GUEST_IA32_PAT */
-		vmx->vcpu.arch.pat = host_pat;
-	}
+	if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT)
+		vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat);
 
 	for (i = 0; i < ARRAY_SIZE(vmx_msr_index); ++i) {
 		u32 index = vmx_msr_index[i];

arch/x86/kvm/x86.c

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c42134e..cdccbe1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7408,6 +7408,8 @@
 
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
 
+	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;
+
 	kvm_async_pf_hash_reset(vcpu);
 	kvm_pmu_init(vcpu);
 

arch/x86/kvm/x86.h

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index f5fef18..01a1d01 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -4,6 +4,8 @@
 #include <linux/kvm_host.h>
 #include "kvm_cache_regs.h"
 
+#define MSR_IA32_CR_PAT_DEFAULT  0x0007040600070406ULL
+
 static inline void kvm_clear_exception_queue(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.exception.pending = false;