[PATCH] kvm: optimize inline assembly

Forms like "0(%rsp)" generate an instruction with an unnecessary one byte
displacement under certain circumstances.  replace with the equivalent
"(%rsp)".

Signed-off-by: Avi Kivity <avi@qumranet.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 27e05a77e21a5645e07dada6717609822de7aea5..5cc1a6ec0174a841a41c18a106a4f9bb6cba5d90 100644 (file)
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1786,10 +1786,10 @@ again:
                "kvm_vmx_return: "
                /* Save guest registers, load host registers, keep flags */
 #ifdef CONFIG_X86_64
-               "xchg %3,     0(%%rsp) \n\t"
+               "xchg %3,     (%%rsp) \n\t"
                "mov %%rax, %c[rax](%3) \n\t"
                "mov %%rbx, %c[rbx](%3) \n\t"
-               "pushq 0(%%rsp); popq %c[rcx](%3) \n\t"
+               "pushq (%%rsp); popq %c[rcx](%3) \n\t"
                "mov %%rdx, %c[rdx](%3) \n\t"
                "mov %%rsi, %c[rsi](%3) \n\t"
                "mov %%rdi, %c[rdi](%3) \n\t"
@@ -1804,24 +1804,24 @@ again:
                "mov %%r15, %c[r15](%3) \n\t"
                "mov %%cr2, %%rax   \n\t"
                "mov %%rax, %c[cr2](%3) \n\t"
-               "mov 0(%%rsp), %3 \n\t"
+               "mov (%%rsp), %3 \n\t"
 
                "pop  %%rcx; pop  %%r15; pop  %%r14; pop  %%r13; pop  %%r12;"
                "pop  %%r11; pop  %%r10; pop  %%r9;  pop  %%r8;"
                "pop  %%rbp; pop  %%rdi; pop  %%rsi;"
                "pop  %%rdx; pop  %%rbx; pop  %%rax \n\t"
 #else
-               "xchg %3, 0(%%esp) \n\t"
+               "xchg %3, (%%esp) \n\t"
                "mov %%eax, %c[rax](%3) \n\t"
                "mov %%ebx, %c[rbx](%3) \n\t"
-               "pushl 0(%%esp); popl %c[rcx](%3) \n\t"
+               "pushl (%%esp); popl %c[rcx](%3) \n\t"
                "mov %%edx, %c[rdx](%3) \n\t"
                "mov %%esi, %c[rsi](%3) \n\t"
                "mov %%edi, %c[rdi](%3) \n\t"
                "mov %%ebp, %c[rbp](%3) \n\t"
                "mov %%cr2, %%eax  \n\t"
                "mov %%eax, %c[cr2](%3) \n\t"
-               "mov 0(%%esp), %3 \n\t"
+               "mov (%%esp), %3 \n\t"
 
                "pop %%ecx; popa \n\t"
 #endif