diff options
| author | Matt Borgerson <contact@mborgerson.com> | 2023-07-13 00:29:01 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-08-04 11:42:18 +0200 |
| commit | b2ea6450d8e1336a33eb958ccc64604bc35a43dd (patch) | |
| tree | 5c4e49ab60b305c6e9cc8fc8040ecf08b210a970 /target/i386 | |
| parent | c26d005e62f4fd177dae0cd70c24cb96761edebc (diff) | |
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.
Signed-off-by: Matt Borgerson <contact@mborgerson.com>
Message-ID: <CADc=-s5F10muEhLs4f3mxqsEPAHWj0XFfOC2sfFMVHrk9fcpMg@mail.gmail.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'target/i386')
| -rw-r--r-- | target/i386/tcg/decode-new.c.inc | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc index 46afd9960b..8f93a239dd 100644 --- a/target/i386/tcg/decode-new.c.inc +++ b/target/i386/tcg/decode-new.c.inc @@ -1803,16 +1803,18 @@ 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_helper_enter_mmx(cpu_env); - } + default: break; } if (!validate_vex(s, &decode)) { return; } + if (decode.e.special == X86_SPECIAL_MMX && + !(s->prefix & (PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA))) { + gen_helper_enter_mmx(cpu_env); + } + 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); } |