KVM: VMX: Move VMREAD cleanup to exception handler
We clean up a failed VMREAD by clearing the output register. Do
it in the exception handler instead of unconditionally. This is
worthwhile since there are more than a hundred call sites.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d48ec60..7d22d6c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -43,6 +43,8 @@
#include "trace.h"
#define __ex(x) __kvm_handle_fault_on_reboot(x)
+#define __ex_clear(x, reg) \
+ ____kvm_handle_fault_on_reboot(x, "xor " reg " , " reg)
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
@@ -587,10 +589,10 @@
static unsigned long vmcs_readl(unsigned long field)
{
- unsigned long value = 0;
+ unsigned long value;
- asm volatile (__ex(ASM_VMX_VMREAD_RDX_RAX)
- : "+a"(value) : "d"(field) : "cc");
+ asm volatile (__ex_clear(ASM_VMX_VMREAD_RDX_RAX, "%0")
+ : "=a"(value) : "d"(field) : "cc");
return value;
}