2 files changed, 76 insertions, 56 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index fc4a6c1235f0..c252efed49d9 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -288,6 +288,10 @@ struct kvm_vcpu {
         u64 apic_base;
         u64 ia32_misc_enable_msr;
         int nmsrs;
+        int save_nmsrs;
+#ifdef CONFIG_X86_64
+        int msr_offset_kernel_gs_base;
+#endif
         struct vmx_msr_entry *guest_msrs;
         struct vmx_msr_entry *host_msrs;
 
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index a05bfa085877..872ca0381fbe 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -85,19 +85,6 @@ static const u32 vmx_msr_index[] = {
 };
 #define NR_VMX_MSR ARRAY_SIZE(vmx_msr_index)
 
-#ifdef CONFIG_X86_64
-static unsigned msr_offset_kernel_gs_base;
-#define NR_64BIT_MSRS 4
-/*
- * avoid save/load MSR_SYSCALL_MASK and MSR_LSTAR by std vt
- * mechanism (cpu bug AA24)
- */
-#define NR_BAD_MSRS 2
-#else
-#define NR_64BIT_MSRS 0
-#define NR_BAD_MSRS 0
-#endif
-
 static inline int is_page_fault(u32 intr_info)
 {
         return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
@@ -118,13 +105,23 @@ static inline int is_external_interrupt(u32 intr_info)
                 == (INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
 }
 
-static struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr)
+static int __find_msr_index(struct kvm_vcpu *vcpu, u32 msr)
 {
         int i;
 
         for (i = 0; i < vcpu->nmsrs; ++i)
                 if (vcpu->guest_msrs[i].index == msr)
-                        return &vcpu->guest_msrs[i];
+                        return i;
+        return -1;
+}
+
+static struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr)
+{
+        int i;
+
+        i = __find_msr_index(vcpu, msr);
+        if (i >= 0)
+                return &vcpu->guest_msrs[i];
         return NULL;
 }
 
@@ -307,10 +304,10 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
 
 #ifdef CONFIG_X86_64
         if (is_long_mode(vcpu)) {
-                save_msrs(vcpu->host_msrs + msr_offset_kernel_gs_base, 1);
-                load_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
+                save_msrs(vcpu->host_msrs + vcpu->msr_offset_kernel_gs_base, 1);
         }
 #endif
+        load_msrs(vcpu->guest_msrs, vcpu->save_nmsrs);
 }
 
 static void vmx_load_host_state(struct kvm_vcpu *vcpu)
@@ -337,12 +334,8 @@ static void vmx_load_host_state(struct kvm_vcpu *vcpu)
 
                 reload_tss();
         }
-#ifdef CONFIG_X86_64
-        if (is_long_mode(vcpu)) {
-                save_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
-                load_msrs(vcpu->host_msrs, NR_BAD_MSRS);
-        }
-#endif
+        save_msrs(vcpu->guest_msrs, vcpu->save_nmsrs);
+        load_msrs(vcpu->host_msrs, vcpu->save_nmsrs);
 }
 
 /*
@@ -464,41 +457,74 @@ static void vmx_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
 }
 
 /*
+ * Swap MSR entry in host/guest MSR entry array.
+ */
+void move_msr_up(struct kvm_vcpu *vcpu, int from, int to)
+{
+        struct vmx_msr_entry tmp;
+        tmp = vcpu->guest_msrs[to];
+        vcpu->guest_msrs[to] = vcpu->guest_msrs[from];
+        vcpu->guest_msrs[from] = tmp;
+        tmp = vcpu->host_msrs[to];
+        vcpu->host_msrs[to] = vcpu->host_msrs[from];
+        vcpu->host_msrs[from] = tmp;
+}
+
+/*
  * Set up the vmcs to automatically save and restore system
  * msrs.  Don't touch the 64-bit msrs if the guest is in legacy
  * mode, as fiddling with msrs is very expensive.
  */
 static void setup_msrs(struct kvm_vcpu *vcpu)
 {
-        int nr_skip, nr_good_msrs;
+        int index, save_nmsrs;
 
-        if (is_long_mode(vcpu))
-                nr_skip = NR_BAD_MSRS;
-        else
-                nr_skip = NR_64BIT_MSRS;
-        nr_good_msrs = vcpu->nmsrs - nr_skip;
+        save_nmsrs = 0;
+#ifdef CONFIG_X86_64
+        if (is_long_mode(vcpu)) {
+                index = __find_msr_index(vcpu, MSR_SYSCALL_MASK);
+                if (index >= 0)
+                        move_msr_up(vcpu, index, save_nmsrs++);
+                index = __find_msr_index(vcpu, MSR_LSTAR);
+                if (index >= 0)
+                        move_msr_up(vcpu, index, save_nmsrs++);
+                index = __find_msr_index(vcpu, MSR_CSTAR);
+                if (index >= 0)
+                        move_msr_up(vcpu, index, save_nmsrs++);
+                index = __find_msr_index(vcpu, MSR_KERNEL_GS_BASE);
+                if (index >= 0)
+                        move_msr_up(vcpu, index, save_nmsrs++);
+                /*
+                 * MSR_K6_STAR is only needed on long mode guests, and only
+                 * if efer.sce is enabled.
+                 */
+                index = __find_msr_index(vcpu, MSR_K6_STAR);
+                if ((index >= 0) && (vcpu->shadow_efer & EFER_SCE))
+                        move_msr_up(vcpu, index, save_nmsrs++);
+        }
+#endif
+        vcpu->save_nmsrs = save_nmsrs;
 
-        /*
-         * MSR_K6_STAR is only needed on long mode guests, and only
-         * if efer.sce is enabled.
-         */
-        if (find_msr_entry(vcpu, MSR_K6_STAR)) {
-                --nr_good_msrs;
 #ifdef CONFIG_X86_64
-                if (is_long_mode(vcpu) && (vcpu->shadow_efer & EFER_SCE))
-                        ++nr_good_msrs;
+        vcpu->msr_offset_kernel_gs_base =
+                __find_msr_index(vcpu, MSR_KERNEL_GS_BASE);
 #endif
+        index = __find_msr_index(vcpu, MSR_EFER);
+        if (index >= 0)
+                save_nmsrs = 1;
+        else {
+                save_nmsrs = 0;
+                index = 0;
         }
-
         vmcs_writel(VM_ENTRY_MSR_LOAD_ADDR,
-                    virt_to_phys(vcpu->guest_msrs + nr_skip));
+                    virt_to_phys(vcpu->guest_msrs + index));
         vmcs_writel(VM_EXIT_MSR_STORE_ADDR,
-                    virt_to_phys(vcpu->guest_msrs + nr_skip));
+                    virt_to_phys(vcpu->guest_msrs + index));
         vmcs_writel(VM_EXIT_MSR_LOAD_ADDR,
-                    virt_to_phys(vcpu->host_msrs + nr_skip));
-        vmcs_write32(VM_EXIT_MSR_STORE_COUNT, nr_good_msrs); /* 22.2.2 */
-        vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, nr_good_msrs);  /* 22.2.2 */
-        vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, nr_good_msrs); /* 22.2.2 */
+                    virt_to_phys(vcpu->host_msrs + index));
+        vmcs_write32(VM_EXIT_MSR_STORE_COUNT, save_nmsrs);
+        vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, save_nmsrs);
+        vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, save_nmsrs);
 }
 
 /*
@@ -595,14 +621,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
         case MSR_GS_BASE:
                 vmcs_writel(GUEST_GS_BASE, data);
                 break;
-        case MSR_LSTAR:
-        case MSR_SYSCALL_MASK:
-                msr = find_msr_entry(vcpu, msr_index);
-                if (msr)
-                        msr->data = data;
-                if (vcpu->vmx_host_state.loaded)
-                        load_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
-                break;
 #endif
         case MSR_IA32_SYSENTER_CS:
                 vmcs_write32(GUEST_SYSENTER_CS, data);
@@ -620,6 +638,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
                 msr = find_msr_entry(vcpu, msr_index);
                 if (msr) {
                         msr->data = data;
+                        if (vcpu->vmx_host_state.loaded)
+                                load_msrs(vcpu->guest_msrs,vcpu->save_nmsrs);
                         break;
                 }
                 return kvm_set_msr_common(vcpu, msr_index, data);
@@ -1331,10 +1351,6 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
                 vcpu->host_msrs[j].reserved = 0;
                 vcpu->host_msrs[j].data = data;
                 vcpu->guest_msrs[j] = vcpu->host_msrs[j];
-#ifdef CONFIG_X86_64
-                if (index == MSR_KERNEL_GS_BASE)
-                        msr_offset_kernel_gs_base = j;
-#endif
                 ++vcpu->nmsrs;
         }