iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: VMX: Do not declare vmread_error() asmlinkage

Browse Source 
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: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220817144045.3206-1-ubizjak@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Uros Bizjak 2022-08-17 16:40:45 +02:00 committed by Paolo Bonzini
parent e390f4d69d
commit 57abfa11ba
3 changed files with 5 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/x86/kvm/vmx/vmenter.S
View File

@ -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)

2
arch/x86/kvm/vmx/vmx.c
View File

@ -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();

2
arch/x86/kvm/vmx/vmx_ops.h
View File

@ -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);