Re: [PATCH] selftests: kvm: Use a shorter encoding to clear RAX

2020-08-18 Thread Yang Weijiang
On Mon, Aug 17, 2020 at 01:20:34PM -0400, Paolo Bonzini wrote: > From: Yang Weijiang > > If debug_regs.c is built with newer binutils, the resulting binary is > "optimized" > by the assembler: > > asm volatile("ss_start: " > "xor %%rax,%%rax\n\t" > "cpuid\n\t" >

Re: [PATCH] selftests: kvm: Use a shorter encoding to clear RAX

2020-08-17 Thread Sean Christopherson
On Mon, Aug 17, 2020 at 01:20:34PM -0400, Paolo Bonzini wrote: > From: Yang Weijiang This shouldn't be here without Weijiang's SOB. > If debug_regs.c is built with newer binutils, the resulting binary is > "optimized" > by the assembler: > > asm volatile("ss_start: " > "xor %%rax,

[PATCH] selftests: kvm: Use a shorter encoding to clear RAX

2020-08-17 Thread Paolo Bonzini
From: Yang Weijiang If debug_regs.c is built with newer binutils, the resulting binary is "optimized" by the assembler: asm volatile("ss_start: " "xor %%rax,%%rax\n\t" "cpuid\n\t" "movl $0x1a0,%%ecx\n\t" "rdmsr\n\t" : : : "rax", "