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x86emul: correct {,F}CMOV and F{,U}COMI{,P} emulation
The FPU ones need to be executed with guest EFLAGS.{C,P,Z}F in context.
We also can't exclude someone wanting to hide the feature from (32-bit)
guests.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This commit is contained in:
Jan Beulich committed
1 parent
610b4eda2c
commit
de05bd965a
1 file changed
+29
-6
@@ -879,6 +879,24 @@ do { \
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put_stub(stub); \
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} while (0)
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#define emulate_fpu_insn_stub_eflags(bytes...) \
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do { \
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unsigned int nr_ = sizeof((uint8_t[]){ bytes }); \
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struct fpu_insn_ctxt fic_ = { .insn_bytes = nr_ }; \
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unsigned long tmp_; \
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memcpy(get_stub(stub), ((uint8_t[]){ bytes, 0xc3 }), nr_ + 1); \
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get_fpu(X86EMUL_FPU_fpu, &fic_); \
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asm volatile ( _PRE_EFLAGS("[eflags]", "[mask]", "[tmp]") \
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"call *%[func];" \
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_POST_EFLAGS("[eflags]", "[mask]", "[tmp]") \
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: [eflags] "+g" (_regs.eflags), \
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[tmp] "=&r" (tmp_) \
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: [func] "rm" (stub.func), \
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[mask] "i" (EFLG_ZF|EFLG_PF|EFLG_CF) ); \
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put_fpu(&fic_); \
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put_stub(stub); \
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} while (0)
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static unsigned long _get_rep_prefix(
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const struct cpu_user_regs *int_regs,
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int ad_bytes)
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@@ -1242,6 +1260,7 @@ static bool_t vcpu_has(
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#define vcpu_must_have(leaf, reg, bit) \
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generate_exception_if(!vcpu_has(leaf, reg, bit, ctxt, ops), EXC_UD, -1)
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#define vcpu_must_have_fpu() vcpu_must_have(0x00000001, EDX, 0)
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#define vcpu_must_have_cmov() vcpu_must_have(0x00000001, EDX, 15)
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#define vcpu_must_have_mmx() vcpu_must_have(0x00000001, EDX, 23)
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#define vcpu_must_have_sse() vcpu_must_have(0x00000001, EDX, 25)
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#define vcpu_must_have_sse2() vcpu_must_have(0x00000001, EDX, 26)
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@@ -3573,6 +3592,9 @@ x86_emulate(
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case 0xc8 ... 0xcf: /* fcmove %stN */
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case 0xd0 ... 0xd7: /* fcmovbe %stN */
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case 0xd8 ... 0xdf: /* fcmovu %stN */
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vcpu_must_have_cmov();
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emulate_fpu_insn_stub_eflags(0xda, modrm);
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break;
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case 0xe9: /* fucompp */
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emulate_fpu_insn_stub(0xda, modrm);
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break;
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@@ -3621,7 +3643,10 @@ x86_emulate(
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case 0xc8 ... 0xcf: /* fcmovne %stN */
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case 0xd0 ... 0xd7: /* fcmovnbe %stN */
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case 0xd8 ... 0xdf: /* fcmovnu %stN */
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emulate_fpu_insn_stub(0xdb, modrm);
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case 0xe8 ... 0xef: /* fucomi %stN */
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case 0xf0 ... 0xf7: /* fcomi %stN */
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vcpu_must_have_cmov();
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emulate_fpu_insn_stub_eflags(0xdb, modrm);
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break;
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case 0xe2: /* fnclex */
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emulate_fpu_insn("fnclex");
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@@ -3631,10 +3656,6 @@ x86_emulate(
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break;
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case 0xe4: /* fsetpm - 287 only, ignored by 387 */
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break;
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case 0xe8 ... 0xef: /* fucomi %stN */
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case 0xf0 ... 0xf7: /* fcomi %stN */
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emulate_fpu_insn_stub(0xdb, modrm);
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break;
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default:
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fail_if(modrm >= 0xc0);
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switch ( modrm_reg & 7 )
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@@ -3852,7 +3873,8 @@ x86_emulate(
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break;
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case 0xe8 ... 0xef: /* fucomip %stN */
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case 0xf0 ... 0xf7: /* fcomip %stN */
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emulate_fpu_insn_stub(0xdf, modrm);
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vcpu_must_have_cmov();
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emulate_fpu_insn_stub_eflags(0xdf, modrm);
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break;
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default:
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fail_if(modrm >= 0xc0);
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@@ -4760,6 +4782,7 @@ x86_emulate(
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}
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case X86EMUL_OPC(0x0f, 0x40) ... X86EMUL_OPC(0x0f, 0x4f): /* cmovcc */
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vcpu_must_have_cmov();
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dst.val = src.val;
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if ( !test_cc(b, _regs.eflags) )
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dst.type = OP_NONE;
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