Commit 907d1393 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Paolo Bonzini
Browse files

KVM: VMX: Provide vmread version using asm-goto-with-outputs 



Use asm-goto-output for smaller fast path code.

Message-Id: <YbcbbGW2GcMx6KpD@hirez.programming.kicks-ass.net>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 55749769

arch/x86/kvm/vmx/vmx_ops.h

+27 −0
Original line number Diff line number Diff line
@@ -71,6 +71,31 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field) 
{

	unsigned long value;



#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT



	asm_volatile_goto("1: vmread %[field], %[output]\n\t"

			  "jna %l[do_fail]\n\t"



			  _ASM_EXTABLE(1b, %l[do_exception])



			  : [output] "=r" (value)

			  : [field] "r" (field)

			  : "cc"

			  : do_fail, do_exception);



	return value;



do_fail:

	WARN_ONCE(1, "kvm: vmread failed: field=%lx\n", field);

	pr_warn_ratelimited("kvm: vmread failed: field=%lx\n", field);

	return 0;



do_exception:

	kvm_spurious_fault();

	return 0;



#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */



	asm volatile("1: vmread %2, %1\n\t"

		     ".byte 0x3e\n\t" /* branch taken hint */

		     "ja 3f\n\t"
@@ -101,6 +126,8 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field) 
		     _ASM_EXTABLE(1b, 4b)

		     : ASM_CALL_CONSTRAINT, "=r"(value) : "r"(field) : "cc");

	return value;



#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */

}



static __always_inline u16 vmcs_read16(unsigned long field)