Re: [PATCH kvm-unit-tests] Update AMD instructions to conform to LLVM assembler

* Re: [PATCH kvm-unit-tests] Update AMD instructions to conform to LLVM assembler
       [not found] <20190220202442.145494-1-pshier@google.com>
@ 2019-12-11 20:22 ` Jim Mattson
  2019-12-12  0:40   ` Paolo Bonzini
  2019-12-18 17:33   ` Paolo Bonzini
  2019-12-14 19:05 ` Fangrui Song
  1 sibling, 2 replies; 4+ messages in thread
From: Jim Mattson @ 2019-12-11 20:22 UTC (permalink / raw)
  To: Peter Shier; +Cc: kvm list, drjones, Paolo Bonzini

On Wed, Feb 20, 2019 at 12:25 PM Peter Shier <pshier@google.com> wrote:
>
> The GNU assembler (gas) allows omitting operands where there is only a
> single choice e.g. "VMRUN rAX".The LLVM assembler requires those operands
> even though they are the default and only choice.
>
> In addition, LLVM does not allow a CLGI instruction with a terminating
> \n\t. Adding a ; separator after the instruction is a workaround.
>
> Signed-off-by: Peter Shier <pshier@google.com>
> Reviewed-by: Marc Orr <marcorr@google.com>
> Reviewed-by: Jim Mattson <jmattson@google.com>
> ---
>  x86/svm.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/x86/svm.c b/x86/svm.c
> index bc74e7c690a8..e5cb730b08cb 100644
> --- a/x86/svm.c
> +++ b/x86/svm.c
> @@ -154,7 +154,7 @@ static void vmcb_ident(struct vmcb *vmcb)
>      struct descriptor_table_ptr desc_table_ptr;
>
>      memset(vmcb, 0, sizeof(*vmcb));
> -    asm volatile ("vmsave" : : "a"(vmcb_phys) : "memory");
> +    asm volatile ("vmsave %0" : : "a"(vmcb_phys) : "memory");
>      vmcb_set_seg(&save->es, read_es(), 0, -1U, data_seg_attr);
>      vmcb_set_seg(&save->cs, read_cs(), 0, -1U, code_seg_attr);
>      vmcb_set_seg(&save->ss, read_ss(), 0, -1U, data_seg_attr);
> @@ -262,20 +262,20 @@ static void test_run(struct test *test, struct vmcb *vmcb)
>      do {
>          tsc_start = rdtsc();
>          asm volatile (
> -            "clgi \n\t"
> -            "vmload \n\t"
> +            "clgi;\n\t" // semi-colon needed for LLVM compatibility
> +            "vmload %0\n\t"
>              "mov regs+0x80, %%r15\n\t"  // rflags
>              "mov %%r15, 0x170(%0)\n\t"
>              "mov regs, %%r15\n\t"       // rax
>              "mov %%r15, 0x1f8(%0)\n\t"
>              LOAD_GPR_C
> -            "vmrun \n\t"
> +            "vmrun %0\n\t"
>              SAVE_GPR_C
>              "mov 0x170(%0), %%r15\n\t"  // rflags
>              "mov %%r15, regs+0x80\n\t"
>              "mov 0x1f8(%0), %%r15\n\t"  // rax
>              "mov %%r15, regs\n\t"
> -            "vmsave \n\t"
> +            "vmsave %0\n\t"
>              "stgi"
>              : : "a"(vmcb_phys)
>              : "rbx", "rcx", "rdx", "rsi",
> @@ -330,7 +330,7 @@ static bool check_no_vmrun_int(struct test *test)
>
>  static void test_vmrun(struct test *test)
>  {
> -    asm volatile ("vmrun" : : "a"(virt_to_phys(test->vmcb)));
> +    asm volatile ("vmrun %0" : : "a"(virt_to_phys(test->vmcb)));
>  }
>
>  static bool check_vmrun(struct test *test)
> @@ -1241,7 +1241,7 @@ static bool lat_svm_insn_finished(struct test *test)
>
>      for ( ; runs != 0; runs--) {
>          tsc_start = rdtsc();
> -        asm volatile("vmload\n\t" : : "a"(vmcb_phys) : "memory");
> +        asm volatile("vmload %0\n\t" : : "a"(vmcb_phys) : "memory");
>          cycles = rdtsc() - tsc_start;
>          if (cycles > latvmload_max)
>              latvmload_max = cycles;
> @@ -1250,7 +1250,7 @@ static bool lat_svm_insn_finished(struct test *test)
>          vmload_sum += cycles;
>
>          tsc_start = rdtsc();
> -        asm volatile("vmsave\n\t" : : "a"(vmcb_phys) : "memory");
> +        asm volatile("vmsave %0\n\t" : : "a"(vmcb_phys) : "memory");
>          cycles = rdtsc() - tsc_start;
>          if (cycles > latvmsave_max)
>              latvmsave_max = cycles;

Ping.

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