Commit 57abfa11 authored by Uros Bizjak's avatar Uros Bizjak Committed by Paolo Bonzini
Browse files

KVM: VMX: Do not declare vmread_error() asmlinkage 



There is no need to declare vmread_error() asmlinkage, its arguments
can be passed via registers for both 32-bit and 64-bit targets.
Function argument registers are considered call-clobbered registers,
they are saved in the trampoline just before the function call and
restored afterwards.

Dropping "asmlinkage" patch unifies trampoline function argument handling
between 32-bit and 64-bit targets and improves generated code for 32-bit
targets.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: default avatarUros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220817144045.3206-1-ubizjak@gmail.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e390f4d6

arch/x86/kvm/vmx/vmenter.S

+3 −12
Original line number Diff line number Diff line
@@ -292,22 +292,13 @@ SYM_FUNC_START(vmread_error_trampoline) 
	push %r10

	push %r11

#endif

#ifdef CONFIG_X86_64



	/* Load @field and @fault to arg1 and arg2 respectively. */

	mov 3*WORD_SIZE(%rbp), %_ASM_ARG2

	mov 2*WORD_SIZE(%rbp), %_ASM_ARG1

#else

	/* Parameters are passed on the stack for 32-bit (see asmlinkage). */

	push 3*WORD_SIZE(%ebp)

	push 2*WORD_SIZE(%ebp)

#endif

	mov 3*WORD_SIZE(%_ASM_BP), %_ASM_ARG2

	mov 2*WORD_SIZE(%_ASM_BP), %_ASM_ARG1



	call vmread_error



#ifndef CONFIG_X86_64

	add $8, %esp

#endif



	/* Zero out @fault, which will be popped into the result register. */

	_ASM_MOV $0, 3*WORD_SIZE(%_ASM_BP)

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -439,7 +439,7 @@ do { \ 
	pr_warn_ratelimited(fmt);	\

} while (0)



asmlinkage void vmread_error(unsigned long field, bool fault)

void vmread_error(unsigned long field, bool fault)

{

	if (fault)

		kvm_spurious_fault();

arch/x86/kvm/vmx/vmx_ops.h

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 
#include "vmcs.h"

#include "../x86.h"



asmlinkage void vmread_error(unsigned long field, bool fault);

void vmread_error(unsigned long field, bool fault);

__attribute__((regparm(0))) void vmread_error_trampoline(unsigned long field,

							 bool fault);

void vmwrite_error(unsigned long field, unsigned long value);