KVM: x86 emulator: disable writeback when decode dest operand (36089fed) · Commits · 戴 / test

arch/x86/kvm/emulate.c

+6 −17

Original line number	Diff line number	Diff line
		@@ -2627,9 +2627,6 @@ done_prefixes:

		/* Decode and fetch the destination operand: register or memory. */
		switch (c->d & DstMask) {
		case ImplicitOps:
		/* Special instructions do their own operand decoding. */
		return 0;
		case DstReg:
		decode_register_operand(&c->dst, c,
		c->twobyte && (c->b == 0xb6 \|\| c->b == 0xb7));
		@@ -2664,6 +2661,11 @@ done_prefixes:
		c->regs[VCPU_REGS_RDI]);
		c->dst.val = 0;
		break;
		case ImplicitOps:
		/* Special instructions do their own operand decoding. */
		default:
		c->dst.type = OP_NONE; /* Disable writeback. */
		return 0;
		}

		done:
		@@ -3115,7 +3117,6 @@ special_insn:
		case 0xf5: /* cmc */
		/* complement carry flag from eflags reg */
		ctxt->eflags ^= EFLG_CF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		break;
		case 0xf6 ... 0xf7: /* Grp3 */
		if (!emulate_grp3(ctxt, ops))
		@@ -3123,16 +3124,13 @@ special_insn:
		break;
		case 0xf8: /* clc */
		ctxt->eflags &= ~EFLG_CF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		break;
		case 0xfa: /* cli */
		if (emulator_bad_iopl(ctxt, ops)) {
		emulate_gp(ctxt, 0);
		goto done;
		} else {
		} else
		ctxt->eflags &= ~X86_EFLAGS_IF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		}
		break;
		case 0xfb: /* sti */
		if (emulator_bad_iopl(ctxt, ops)) {
		@@ -3141,16 +3139,13 @@ special_insn:
		} else {
		ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
		ctxt->eflags \|= X86_EFLAGS_IF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		}
		break;
		case 0xfc: /* cld */
		ctxt->eflags &= ~EFLG_DF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		break;
		case 0xfd: /* std */
		ctxt->eflags \|= EFLG_DF;
		c->dst.type = OP_NONE; /* Disable writeback. */
		break;
		case 0xfe: /* Grp4 */
		grp45:
		@@ -3287,16 +3282,13 @@ twobyte_insn:
		break;
		case 0x06:
		emulate_clts(ctxt->vcpu);
		c->dst.type = OP_NONE;
		break;
		case 0x09: /* wbinvd */
		kvm_emulate_wbinvd(ctxt->vcpu);
		c->dst.type = OP_NONE;
		break;
		case 0x08: /* invd */
		case 0x0d: /* GrpP (prefetch) */
		case 0x18: /* Grp16 (prefetch/nop) */
		c->dst.type = OP_NONE;
		break;
		case 0x20: /* mov cr, reg */
		switch (c->modrm_reg) {
		@@ -3349,7 +3341,6 @@ twobyte_insn:
		goto done;
		}
		rc = X86EMUL_CONTINUE;
		c->dst.type = OP_NONE;
		break;
		case 0x32:
		/* rdmsr */
		@@ -3361,7 +3352,6 @@ twobyte_insn:
		c->regs[VCPU_REGS_RDX] = msr_data >> 32;
		}
		rc = X86EMUL_CONTINUE;
		c->dst.type = OP_NONE;
		break;
		case 0x34: /* sysenter */
		rc = emulate_sysenter(ctxt, ops);
		@@ -3385,7 +3375,6 @@ twobyte_insn:
		case 0x80 ... 0x8f: /* jnz rel, etc*/
		if (test_cc(c->b, ctxt->eflags))
		jmp_rel(c, c->src.val);
		c->dst.type = OP_NONE;
		break;
		case 0xa0: /* push fs */
		emulate_push_sreg(ctxt, ops, VCPU_SREG_FS);

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