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

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

Message-Id: <YbcbbGW2GcMx6KpD@hirez.programming.kicks-ass.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Zijlstra 2021-12-13 11:07:40 +01:00 committed by Paolo Bonzini
parent 55749769fe
commit 907d139318
1 changed files with 27 additions and 0 deletions
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27
arch/x86/kvm/vmx/vmx_ops.h
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@ -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)