1 files changed, 8 insertions, 4 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7c1ce5ac6131..3944e917e794 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -338,6 +338,9 @@ EXPORT_SYMBOL_GPL(kvm_lmsw);
 
 void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {
+        unsigned long old_cr4 = vcpu->arch.cr4;
+        unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE;
+
         if (cr4 & CR4_RESERVED_BITS) {
                 printk(KERN_DEBUG "set_cr4: #GP, reserved bits\n");
                 kvm_inject_gp(vcpu, 0);
@@ -351,7 +354,8 @@ void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
                         kvm_inject_gp(vcpu, 0);
                         return;
                 }
-        } else if (is_paging(vcpu) && !is_pae(vcpu) && (cr4 & X86_CR4_PAE)
+        } else if (is_paging(vcpu) && (cr4 & X86_CR4_PAE)
+                   && ((cr4 ^ old_cr4) & pdptr_bits)
                    && !load_pdptrs(vcpu, vcpu->arch.cr3)) {
                 printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
                 kvm_inject_gp(vcpu, 0);
@@ -1121,9 +1125,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 static int is_efer_nx(void)
 {
-        u64 efer;
+        unsigned long long efer = 0;
 
-        rdmsrl(MSR_EFER, efer);
+        rdmsrl_safe(MSR_EFER, &efer);
         return efer & EFER_NX;
 }
 
@@ -1259,7 +1263,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
                 bit(X86_FEATURE_CMOV) | bit(X86_FEATURE_PSE36) |
                 bit(X86_FEATURE_MMX) | bit(X86_FEATURE_FXSR) |
                 bit(X86_FEATURE_SYSCALL) |
-                (bit(X86_FEATURE_NX) && is_efer_nx()) |
+                (is_efer_nx() ? bit(X86_FEATURE_NX) : 0) |
 #ifdef CONFIG_X86_64
                 bit(X86_FEATURE_LM) |
 #endif