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>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b6ad0f9de80a566fa4510b4a87197c0cf9a436e9..8954d7a07703d42d1ba68337c5f19bdd252873ac 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1176,7 +1176,7 @@ static void init_vmcb(struct vcpu_svm *svm, bool init_event)
                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;
        }

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a694ff6bce8029ae91644a7ffffbb5c3cd8f93af..3c218fd59f8c8f101688a22b78b115e69a396599 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4667,16 +4667,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
        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];

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c42134e98e311135a62d6d89c432f7b2f8aff133..cdccbe1749a53165ad1168fa1d4ec7e16d22d4c1 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7408,6 +7408,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
        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);
 

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index f5fef18680964164263c5fb111bf55e68bd3655c..01a1d011e073a8bb60c8226ea4138af2626b4e7f 100644 (file)
--- 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;