Merge branch 'kvm-updates/2.6.30' of git://git.kernel.org/pub/scm/virt/kvm/kvm

* 'kvm-updates/2.6.30' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Remove port 80 passthrough
  KVM: Make EFER reads safe when EFER does not exist
  KVM: Fix NX support reporting
  KVM: SVM: Fix cross vendor migration issue with unusable bit

2 files changed, 8 insertions, 6 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1821c2078199..1f8510c51d6e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -411,7 +411,6 @@ static __init int svm_hardware_setup(void)
 
         iopm_va = page_address(iopm_pages);
         memset(iopm_va, 0xff, PAGE_SIZE * (1 << IOPM_ALLOC_ORDER));
-        clear_bit(0x80, iopm_va); /* allow direct access to PC debug port */
         iopm_base = page_to_pfn(iopm_pages) << PAGE_SHIFT;
 
         if (boot_cpu_has(X86_FEATURE_NX))
@@ -796,6 +795,11 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
         var->db = (s->attrib >> SVM_SELECTOR_DB_SHIFT) & 1;
         var->g = (s->attrib >> SVM_SELECTOR_G_SHIFT) & 1;
 
+        /* AMD's VMCB does not have an explicit unusable field, so emulate it
+         * for cross vendor migration purposes by "not present"
+         */
+        var->unusable = !var->present || (var->type == 0);
+
         switch (seg) {
         case VCPU_SREG_CS:
                 /*
@@ -827,8 +831,6 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
                         var->type |= 0x1;
                 break;
         }
-
-        var->unusable = !var->present;
 }
 
 static int svm_get_cpl(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7c1ce5ac6131..49079a46687b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1121,9 +1121,9 @@ 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 +1259,7 @@ 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