4 files changed, 64 insertions, 20 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 992ab7115871..9390a31c06f4 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -27,6 +27,8 @@
 
 #include <asm/desc.h>
 
+#define __ex(x) __kvm_handle_fault_on_reboot(x)
+
 MODULE_AUTHOR("Qumranet");
 MODULE_LICENSE("GPL");
 
@@ -129,17 +131,17 @@ static inline void push_irq(struct kvm_vcpu *vcpu, u8 irq)
 
 static inline void clgi(void)
 {
-        asm volatile (SVM_CLGI);
+        asm volatile (__ex(SVM_CLGI));
 }
 
 static inline void stgi(void)
 {
-        asm volatile (SVM_STGI);
+        asm volatile (__ex(SVM_STGI));
 }
 
 static inline void invlpga(unsigned long addr, u32 asid)
 {
-        asm volatile (SVM_INVLPGA :: "a"(addr), "c"(asid));
+        asm volatile (__ex(SVM_INVLPGA) :: "a"(addr), "c"(asid));
 }
 
 static inline unsigned long kvm_read_cr2(void)
@@ -1758,17 +1760,17 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 /* Enter guest mode */
                 "push %%rax \n\t"
                 "mov %c[vmcb](%[svm]), %%rax \n\t"
-                SVM_VMLOAD "\n\t"
-                SVM_VMRUN "\n\t"
-                SVM_VMSAVE "\n\t"
+                __ex(SVM_VMLOAD) "\n\t"
+                __ex(SVM_VMRUN) "\n\t"
+                __ex(SVM_VMSAVE) "\n\t"
                 "pop %%rax \n\t"
 #else
                 /* Enter guest mode */
                 "push %%eax \n\t"
                 "mov %c[vmcb](%[svm]), %%eax \n\t"
-                SVM_VMLOAD "\n\t"
-                SVM_VMRUN "\n\t"
-                SVM_VMSAVE "\n\t"
+                __ex(SVM_VMLOAD) "\n\t"
+                __ex(SVM_VMRUN) "\n\t"
+                __ex(SVM_VMSAVE) "\n\t"
                 "pop %%eax \n\t"
 #endif
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fff8e23433d6..b80b4d141637 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -30,6 +30,8 @@
 #include <asm/io.h>
 #include <asm/desc.h>
 
+#define __ex(x) __kvm_handle_fault_on_reboot(x)
+
 MODULE_AUTHOR("Qumranet");
 MODULE_LICENSE("GPL");
 
@@ -278,7 +280,7 @@ static inline void __invvpid(int ext, u16 vpid, gva_t gva)
         u64 gva;
     } operand = { vpid, 0, gva };
 
-    asm volatile (ASM_VMX_INVVPID
+    asm volatile (__ex(ASM_VMX_INVVPID)
                   /* CF==1 or ZF==1 --> rc = -1 */
                   "; ja 1f ; ud2 ; 1:"
                   : : "a"(&operand), "c"(ext) : "cc", "memory");
@@ -290,7 +292,7 @@ static inline void __invept(int ext, u64 eptp, gpa_t gpa)
                 u64 eptp, gpa;
         } operand = {eptp, gpa};
 
-        asm volatile (ASM_VMX_INVEPT
+        asm volatile (__ex(ASM_VMX_INVEPT)
                         /* CF==1 or ZF==1 --> rc = -1 */
                         "; ja 1f ; ud2 ; 1:\n"
                         : : "a" (&operand), "c" (ext) : "cc", "memory");
@@ -311,7 +313,7 @@ static void vmcs_clear(struct vmcs *vmcs)
         u64 phys_addr = __pa(vmcs);
         u8 error;
 
-        asm volatile (ASM_VMX_VMCLEAR_RAX "; setna %0"
+        asm volatile (__ex(ASM_VMX_VMCLEAR_RAX) "; setna %0"
                       : "=g"(error) : "a"(&phys_addr), "m"(phys_addr)
                       : "cc", "memory");
         if (error)
@@ -378,7 +380,7 @@ static unsigned long vmcs_readl(unsigned long field)
 {
         unsigned long value;
 
-        asm volatile (ASM_VMX_VMREAD_RDX_RAX
+        asm volatile (__ex(ASM_VMX_VMREAD_RDX_RAX)
                       : "=a"(value) : "d"(field) : "cc");
         return value;
 }
@@ -413,7 +415,7 @@ static void vmcs_writel(unsigned long field, unsigned long value)
 {
         u8 error;
 
-        asm volatile (ASM_VMX_VMWRITE_RAX_RDX "; setna %0"
+        asm volatile (__ex(ASM_VMX_VMWRITE_RAX_RDX) "; setna %0"
                        : "=q"(error) : "a"(value), "d"(field) : "cc");
         if (unlikely(error))
                 vmwrite_error(field, value);
@@ -621,7 +623,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
                 u8 error;
 
                 per_cpu(current_vmcs, cpu) = vmx->vmcs;
-                asm volatile (ASM_VMX_VMPTRLD_RAX "; setna %0"
+                asm volatile (__ex(ASM_VMX_VMPTRLD_RAX) "; setna %0"
                               : "=g"(error) : "a"(&phys_addr), "m"(phys_addr)
                               : "cc");
                 if (error)
@@ -1030,13 +1032,14 @@ static void hardware_enable(void *garbage)
                        MSR_IA32_FEATURE_CONTROL_LOCKED |
                        MSR_IA32_FEATURE_CONTROL_VMXON_ENABLED);
         write_cr4(read_cr4() | X86_CR4_VMXE); /* FIXME: not cpu hotplug safe */
-        asm volatile (ASM_VMX_VMXON_RAX : : "a"(&phys_addr), "m"(phys_addr)
+        asm volatile (ASM_VMX_VMXON_RAX
+                      : : "a"(&phys_addr), "m"(phys_addr)
                       : "memory", "cc");
 }
 
 static void hardware_disable(void *garbage)
 {
-        asm volatile (ASM_VMX_VMXOFF : : : "cc");
+        asm volatile (__ex(ASM_VMX_VMXOFF) : : : "cc");
         write_cr4(read_cr4() & ~X86_CR4_VMXE);
 }
 
@@ -2834,7 +2837,7 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 "push %%edx; push %%ebp;"
                 "push %%ecx \n\t"
 #endif
-                ASM_VMX_VMWRITE_RSP_RDX "\n\t"
+                __ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t"
                 /* Check if vmlaunch of vmresume is needed */
                 "cmpl $0, %c[launched](%0) \n\t"
                 /* Load guest registers.  Don't clobber flags. */
@@ -2869,9 +2872,9 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 #endif
                 /* Enter guest mode */
                 "jne .Llaunched \n\t"
-                ASM_VMX_VMLAUNCH "\n\t"
+                __ex(ASM_VMX_VMLAUNCH) "\n\t"
                 "jmp .Lkvm_vmx_return \n\t"
-                ".Llaunched: " ASM_VMX_VMRESUME "\n\t"
+                ".Llaunched: " __ex(ASM_VMX_VMRESUME) "\n\t"
                 ".Lkvm_vmx_return: "
                 /* Save guest registers, load host registers, keep flags */
 #ifdef CONFIG_X86_64
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index c2d066e185f4..0df9d5fa281a 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -692,4 +692,28 @@ enum {
         trace_mark(kvm_trace_##name, "%u %p %u %u %u %u %u %u", KVM_TRC_##evt, \
                                                 vcpu, 0, 0, 0, 0, 0, 0)
 
+#ifdef CONFIG_64BIT
+#define KVM_EX_ENTRY ".quad"
+#else
+#define KVM_EX_ENTRY ".long"
+#endif
+
+/*
+ * Hardware virtualization extension instructions may fault if a
+ * reboot turns off virtualization while processes are running.
+ * Trap the fault and ignore the instruction if that happens.
+ */
+asmlinkage void kvm_handle_fault_on_reboot(void);
+
+#define __kvm_handle_fault_on_reboot(insn) \
+        "666: " insn "\n\t" \
+        ".pushsection .text.fixup, \"ax\" \n" \
+        "667: \n\t" \
+        "push $666b \n\t" \
+        "jmp kvm_handle_fault_on_reboot \n\t" \
+        ".popsection \n\t" \
+        ".pushsection __ex_table, \"a\" \n\t" \
+        KVM_EX_ENTRY " 666b, 667b \n\t" \
+        ".popsection"
+
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f9dd20606c40..e4bf88a9ee4e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -65,6 +65,8 @@ struct dentry *kvm_debugfs_dir;
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                            unsigned long arg);
 
+bool kvm_rebooting;
+
 static inline int valid_vcpu(int n)
 {
         return likely(n >= 0 && n < KVM_MAX_VCPUS);
@@ -1301,6 +1303,18 @@ static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
         return NOTIFY_OK;
 }
 
+
+asmlinkage void kvm_handle_fault_on_reboot(void)
+{
+        if (kvm_rebooting)
+                /* spin while reset goes on */
+                while (true)
+                        ;
+        /* Fault while not rebooting.  We want the trace. */
+        BUG();
+}
+EXPORT_SYMBOL_GPL(kvm_handle_fault_on_reboot);
+
 static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
                       void *v)
 {
@@ -1310,6 +1324,7 @@ static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
                  * in vmx root mode.
                  */
                 printk(KERN_INFO "kvm: exiting hardware virtualization\n");
+                kvm_rebooting = true;
                 on_each_cpu(hardware_disable, NULL, 1);
         }
         return NOTIFY_OK;