Commit 77892e1f authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

KVM: x86: Convert em_salc() to C 



Implement the SALC (Set AL if Carry) instruction in C.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarSean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/20250714103440.634145269@infradead.org
parent 2d82acd7

arch/x86/kvm/emulate.c

+9 −6
Original line number Diff line number Diff line
@@ -529,11 +529,14 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop); 
	ON64(FOP3E(op##q, rax, rdx, cl)) \

	FOP_END



FOP_START(salc)

FOP_FUNC(salc)

"pushf; sbb %al, %al; popf \n\t"

FOP_RET(salc)

FOP_END;

static int em_salc(struct x86_emulate_ctxt *ctxt)

{

	/*

	 * Set AL 0xFF if CF is set, or 0x00 when clear.

	 */

	ctxt->dst.val = 0xFF * !!(ctxt->eflags & X86_EFLAGS_CF);

	return X86EMUL_CONTINUE;

}



/*

 * XXX: inoutclob user must know where the argument is being expanded.
@@ -4423,7 +4426,7 @@ static const struct opcode opcode_table[256] = { 
	G(Src2CL | ByteOp, group2), G(Src2CL, group2),

	I(DstAcc | SrcImmUByte | No64, em_aam),

	I(DstAcc | SrcImmUByte | No64, em_aad),

	F(DstAcc | ByteOp | No64, em_salc),

	I(DstAcc | ByteOp | No64, em_salc),

	I(DstAcc | SrcXLat | ByteOp, em_mov),

	/* 0xD8 - 0xDF */

	N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,