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[PATCH 24/25] target/i386: do not check PREFIX_LOCK in old-style decoder

Paolo Bonzini posted 25 patches 5 months, 2 weeks ago
There is a newer version of this series
[PATCH 24/25] target/i386: do not check PREFIX_LOCK in old-style decoder
Posted by Paolo Bonzini 5 months, 2 weeks ago 
It is already checked before getting there.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 67f2e792166..ee5ef3ccbc6 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -2993,7 +2993,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
 
         case 7: /* RDSEED, RDPID with f3 prefix */
             if (mod != 3 ||
-                (s->prefix & (PREFIX_LOCK | PREFIX_REPNZ))) {
+                (s->prefix & PREFIX_REPNZ)) {
                 goto illegal_op;
             }
             if (s->prefix & PREFIX_REPZ) {
@@ -3013,7 +3013,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
 
         case 6: /* RDRAND */
             if (mod != 3 ||
-                (s->prefix & (PREFIX_LOCK | PREFIX_REPZ | PREFIX_REPNZ)) ||
+                (s->prefix & (PREFIX_REPZ | PREFIX_REPNZ)) ||
                 !(s->cpuid_ext_features & CPUID_EXT_RDRAND)) {
                 goto illegal_op;
             }
@@ -3173,8 +3173,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
 
         case 0xd0: /* xgetbv */
             if ((s->cpuid_ext_features & CPUID_EXT_XSAVE) == 0
-                || (s->prefix & (PREFIX_LOCK | PREFIX_DATA
-                                 | PREFIX_REPZ | PREFIX_REPNZ))) {
+                || (s->prefix & (PREFIX_DATA | PREFIX_REPZ | PREFIX_REPNZ))) {
                 goto illegal_op;
             }
             tcg_gen_trunc_tl_i32(s->tmp2_i32, cpu_regs[R_ECX]);
@@ -3184,8 +3183,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
 
         case 0xd1: /* xsetbv */
             if ((s->cpuid_ext_features & CPUID_EXT_XSAVE) == 0
-                || (s->prefix & (PREFIX_LOCK | PREFIX_DATA
-                                 | PREFIX_REPZ | PREFIX_REPNZ))) {
+                || (s->prefix & (PREFIX_DATA | PREFIX_REPZ | PREFIX_REPNZ))) {
                 goto illegal_op;
             }
             gen_svm_check_intercept(s, SVM_EXIT_XSETBV);
@@ -3352,8 +3350,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             gen_st_modrm(s, decode, ot);
             break;
         case 0xee: /* rdpkru */
-            if (s->prefix & (PREFIX_LOCK | PREFIX_DATA
-                             | PREFIX_REPZ | PREFIX_REPNZ)) {
+            if (s->prefix & (PREFIX_DATA | PREFIX_REPZ | PREFIX_REPNZ)) {
                 goto illegal_op;
             }
             tcg_gen_trunc_tl_i32(s->tmp2_i32, cpu_regs[R_ECX]);
@@ -3361,8 +3358,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             tcg_gen_extr_i64_tl(cpu_regs[R_EAX], cpu_regs[R_EDX], s->tmp1_i64);
             break;
         case 0xef: /* wrpkru */
-            if (s->prefix & (PREFIX_LOCK | PREFIX_DATA
-                             | PREFIX_REPZ | PREFIX_REPNZ)) {
+            if (s->prefix & (PREFIX_DATA | PREFIX_REPZ | PREFIX_REPNZ)) {
                 goto illegal_op;
             }
             tcg_gen_concat_tl_i64(s->tmp1_i64, cpu_regs[R_EAX],
@@ -3438,7 +3434,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             if (prefixes & PREFIX_REPZ) {
                 /* bndcl */
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16) {
                     goto illegal_op;
                 }
@@ -3446,7 +3441,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             } else if (prefixes & PREFIX_REPNZ) {
                 /* bndcu */
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16) {
                     goto illegal_op;
                 }
@@ -3460,7 +3454,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
                 }
                 if (mod == 3) {
                     int reg2 = (modrm & 7) | REX_B(s);
-                    if (reg2 >= 4 || (prefixes & PREFIX_LOCK)) {
+                    if (reg2 >= 4) {
                         goto illegal_op;
                     }
                     if (s->flags & HF_MPX_IU_MASK) {
@@ -3489,7 +3483,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
                 /* bndldx */
                 AddressParts a = decode->mem;
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16
                     || a.base < -1) {
                     goto illegal_op;
@@ -3525,7 +3518,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             if (mod != 3 && (prefixes & PREFIX_REPZ)) {
                 /* bndmk */
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16) {
                     goto illegal_op;
                 }
@@ -3553,7 +3545,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
             } else if (prefixes & PREFIX_REPNZ) {
                 /* bndcn */
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16) {
                     goto illegal_op;
                 }
@@ -3565,7 +3556,7 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
                 }
                 if (mod == 3) {
                     int reg2 = (modrm & 7) | REX_B(s);
-                    if (reg2 >= 4 || (prefixes & PREFIX_LOCK)) {
+                    if (reg2 >= 4) {
                         goto illegal_op;
                     }
                     if (s->flags & HF_MPX_IU_MASK) {
@@ -3592,7 +3583,6 @@ static void gen_multi0F(DisasContext *s, X86DecodedInsn *decode)
                 /* bndstx */
                 AddressParts a = decode->mem;
                 if (reg >= 4
-                    || (prefixes & PREFIX_LOCK)
                     || s->aflag == MO_16
                     || a.base < -1) {
                     goto illegal_op;
-- 
2.45.1
Re: [PATCH 24/25] target/i386: do not check PREFIX_LOCK in old-style decoder
Posted by Richard Henderson 5 months, 2 weeks ago 
On 6/8/24 01:41, Paolo Bonzini wrote:
> It is already checked before getting there.
> 
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
>   target/i386/tcg/translate.c | 26 ++++++++------------------
>   1 file changed, 8 insertions(+), 18 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
Re: [PATCH 24/25] target/i386: do not check PREFIX_LOCK in old-style decoder
Posted by Paolo Bonzini 5 months, 2 weeks ago 
On Sat, Jun 8, 2024 at 10:16 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 6/8/24 01:41, Paolo Bonzini wrote:
> > It is already checked before getting there.
> >
> > Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> > ---
> >   target/i386/tcg/translate.c | 26 ++++++++------------------
> >   1 file changed, 8 insertions(+), 18 deletions(-)
>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

... except cmpxchg8b/cmpxchg16b do have to accept LOCK. Fortunately
it's trivial to convert them, with just an ugly temporary

    if (decode.e.gen == gen_multi0F) {
        accept_lock = true;
    }

that only lasts one commit. I'll resend this part of the series later
(and BTx as well).

Paolo

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