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Commit 7d88bb48 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Avi Kivity
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KVM: x86 emulator: Let compiler know insn_fetch() rarely fails 



Fetching the instruction which was to be executed by the guest cannot
fail normally.  So compiler should always predict that it will succeed.

Signed-off-by: default avatarTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent e85a1085

arch/x86/kvm/emulate.c

+3 −3
Original line number Diff line number Diff line
@@ -672,11 +672,11 @@ static int do_insn_fetch_byte(struct x86_emulate_ctxt *ctxt, u8 *dest) 
		size = min(15UL - cur_size,

			   PAGE_SIZE - offset_in_page(ctxt->_eip));

		rc = __linearize(ctxt, addr, size, false, true, &linear);

		if (rc != X86EMUL_CONTINUE)

		if (unlikely(rc != X86EMUL_CONTINUE))

			return rc;

		rc = ctxt->ops->fetch(ctxt, linear, fc->data + cur_size,

				      size, &ctxt->exception);

		if (rc != X86EMUL_CONTINUE)

		if (unlikely(rc != X86EMUL_CONTINUE))

			return rc;

		fc->end += size;

	}
@@ -691,7 +691,7 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt, 
	int rc;



	/* x86 instructions are limited to 15 bytes. */

	if (ctxt->_eip + size - ctxt->eip > 15)

	if (unlikely(ctxt->_eip + size - ctxt->eip > 15))

		return X86EMUL_UNHANDLEABLE;

	while (size--) {

		rc = do_insn_fetch_byte(ctxt, dest++);