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Re: [PATCH] target/i386: implement undocumented "smsw r32" behavior
From: |
Roman Bolshakov |
Subject: |
Re: [PATCH] target/i386: implement undocumented "smsw r32" behavior |
Date: |
Thu, 2 Jul 2020 12:37:17 +0300 |
On Fri, Jun 26, 2020 at 06:44:19AM -0400, Paolo Bonzini wrote:
> In 32-bit mode, the higher 16 bits of the destination
> register are undefined. In practice CR0[31:0] is stored,
> just like in 64-bit mode, so just remove the "if" that
> currently differentiates the behavior.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Hi Paolo,
It seems to be a follow-up to the kvm-unit-tests patch:
https://patchwork.kernel.org/patch/11590445/
Could you please add:
Reported-by: Roman Bolshakov <r.bolshakov@yadro.com>
> ---
> target/i386/translate.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/target/i386/translate.c b/target/i386/translate.c
> index 4d808a6f93..60eac03498 100644
> --- a/target/i386/translate.c
> +++ b/target/i386/translate.c
> @@ -7579,12 +7579,13 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
> CASE_MODRM_OP(4): /* smsw */
> gen_svm_check_intercept(s, pc_start, SVM_EXIT_READ_CR0);
> tcg_gen_ld_tl(s->T0, cpu_env, offsetof(CPUX86State, cr[0]));
> - if (CODE64(s)) {
> - mod = (modrm >> 6) & 3;
> - ot = (mod != 3 ? MO_16 : s->dflag);
> - } else {
> - ot = MO_16;
> - }
> + /*
> + * In 32-bit mode, the higher 16 bits of the destination
> + * register are undefined. In practice CR0[31:0] is stored
> + * just like in 64-bit mode.
> + */
> + mod = (modrm >> 6) & 3;
> + ot = (mod != 3 ? MO_16 : s->dflag);
> gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 1);
> break;
> case 0xee: /* rdpkru */
> --
> 2.26.2
>
>
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Regards,
Roman