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KVM: x86: add asm_safe wrapper

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commit aabba3c6abd50b05b1fc2c6ec44244aa6bcda576 upstream.

Move the existing exception handling for inline assembly into a macro
and switch its return values to X86EMUL type.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Radim Krčmář 2016-11-08 20:54:18 +01:00 • committed by Greg Kroah-Hartman
parent 4fa0090249
commit d9c4c1e7c2
1 changed files with 23 additions and 11 deletions
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34
arch/x86/kvm/emulate.c
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@ -435,6 +435,26 @@ FOP_END;
FOP_START(salc) "pushf; sbb %al, %al; popf \n\t" FOP_RET
FOP_END;
/*
* XXX: inoutclob user must know where the argument is being expanded.
* Relying on CC_HAVE_ASM_GOTO would allow us to remove _fault.
*/
#define asm_safe(insn, inoutclob...) \
({ \
int _fault = 0; \
\
asm volatile("1:" insn "\n" \
"2:\n" \
".pushsection .fixup, \"ax\"\n" \
"3: movl $1, %[_fault]\n" \
" jmp 2b\n" \
".popsection\n" \
_ASM_EXTABLE(1b, 3b) \
: [_fault] "+qm"(_fault) inoutclob ); \
\
_fault ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; \
})
static int emulator_check_intercept(struct x86_emulate_ctxt *ctxt,
enum x86_intercept intercept,
enum x86_intercept_stage stage)
@ -5086,21 +5106,13 @@ static bool string_insn_completed(struct x86_emulate_ctxt *ctxt)
static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
{
bool fault = false;
int rc;
ctxt->ops->get_fpu(ctxt);
asm volatile("1: fwait \n\t"
"2: \n\t"
".pushsection .fixup,\"ax\" \n\t"
"3: \n\t"
"movb $1, %[fault] \n\t"
"jmp 2b \n\t"
".popsection \n\t"
_ASM_EXTABLE(1b, 3b)
: [fault]"+qm"(fault));
rc = asm_safe("fwait");
ctxt->ops->put_fpu(ctxt);
if (unlikely(fault))
if (unlikely(rc != X86EMUL_CONTINUE))
return emulate_exception(ctxt, MF_VECTOR, 0, false);
return X86EMUL_CONTINUE;