On 07/03/2012 12:50 PM, Zhengwang Ruan wrote: > Hi kashyapc & all, > > I see a piece of code in vmx_vcpu_run as below, is it used to switch > context to a guest? Kvm don't used "vmlaunch" or "vmresume" to launch or > resume a guest? You trimmed the bit that contains vmlaunch/vmresume. Why does kvm need to manually switch context by filling > registers using stored register copies? Those registers don't get automatically switched by the hardware. > > =============== > > asm( > /* Store host registers */ > "push %%"R"dx; push %%"R"bp;" > "push %%"R"cx \n\t" /* placeholder for guest rcx */ > "push %%"R"cx \n\t" > "cmp %%"R"sp, %c[host_rsp](%0) \n\t" > "je 1f \n\t" > "mov %%"R"sp, %c[host_rsp](%0) \n\t" > __ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t" > "1: \n\t" > /* Reload cr2 if changed */ > "mov %c[cr2](%0), %%"R"ax \n\t" > "mov %%cr2, %%"R"dx \n\t" > "cmp %%"R"ax, %%"R"dx \n\t" > "je 2f \n\t" > "mov %%"R"ax, %%cr2 \n\t" > "2: \n\t" > /* Check if vmlaunch of vmresume is needed */ > "cmpl $0, %c[launched](%0) \n\t" > /* Load guest registers. Don't clobber flags. */ > "mov %c[rax](%0), %%"R"ax \n\t" > "mov %c[rbx](%0), %%"R"bx \n\t" > "mov %c[rdx](%0), %%"R"dx \n\t" > "mov %c[rsi](%0), %%"R"si \n\t" > "mov %c[rdi](%0), %%"R"di \n\t" > "mov %c[rbp](%0), %%"R"bp \n\t" > -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
