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target/i386: Check CR0.TS before enter_mmx 

When CR0.TS=1, execution of x87 FPU, MMX, and some SSE instructions will
cause a Device Not Available (DNA) exception (#NM). System software uses
this exception event to lazily context switch FPU state.

Before this patch, enter_mmx helpers may be generated just before #NM
generation, prematurely resetting FPU state before the guest has a
chance to save it.
This commit is contained in:
Matt Borgerson 2023-07-15 17:17:27 -07:00
parent 71c8cb62af
commit b5015e99b7
1 changed files with 7 additions and 4 deletions
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11
target/i386/tcg/decode-new.c.inc
View File

@ -1804,16 +1804,19 @@ static void disas_insn_new(DisasContext *s, CPUState *cpu, int b)
}
break;
case X86_SPECIAL_MMX:
if (!(s->prefix & (PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA))) {
gen_enter_mmx(s);
}
default:
break;
}
if (!validate_vex(s, &decode)) {
return;
}
if (decode.e.special == X86_SPECIAL_MMX &&
!(s->prefix & (PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA))) {
gen_enter_mmx(s);
}
if (decode.op[0].has_ea || decode.op[1].has_ea || decode.op[2].has_ea) {
gen_load_ea(s, &decode.mem, decode.e.vex_class == 12);
}