Add support for the 0x81 AND instruction, now generated

by clang in the local APIC code.

0x81 is a read-modify-write instruction - the EPT check
that only allowed read or write and not both has been
relaxed to allow read and write.

Reviewed by:	neel
Obtained from:	NetApp

2 files changed, 34 insertions, 4 deletions

diff --git a/sys/amd64/vmm/intel/vmx.c b/sys/amd64/vmm/intel/vmx.c
index 2b6ef35..4f267bb 100644
--- a/sys/amd64/vmm/intel/vmx.c
+++ b/sys/amd64/vmm/intel/vmx.c
@@ -1159,15 +1159,16 @@ vmx_ept_fault(struct vm *vm, int cpu,
 	if (ept_qual & EPT_VIOLATION_INST_FETCH)
 		return (UNHANDLED);
 
-	/* EPT violation must be a read fault or a write fault but not both */
+	/* EPT violation must be a read fault or a write fault */
 	read = ept_qual & EPT_VIOLATION_DATA_READ ? 1 : 0;
 	write = ept_qual & EPT_VIOLATION_DATA_WRITE ? 1 : 0;
-	if ((read ^ write) == 0)
+	if ((read | write) == 0)
 		return (UNHANDLED);
 
 	/*
-	 * The EPT violation must have been caused by accessing a guest-physical
-	 * address that is a translation of a guest-linear address.
+	 * The EPT violation must have been caused by accessing a
+	 * guest-physical address that is a translation of a guest-linear
+	 * address.
 	 */
 	if ((ept_qual & EPT_VIOLATION_GLA_VALID) == 0 ||
 	    (ept_qual & EPT_VIOLATION_XLAT_VALID) == 0) {
diff --git a/sys/amd64/vmm/vmm_instruction_emul.c b/sys/amd64/vmm/vmm_instruction_emul.c
index 5e5399b..0a7286b 100644
--- a/sys/amd64/vmm/vmm_instruction_emul.c
+++ b/sys/amd64/vmm/vmm_instruction_emul.c
@@ -81,6 +81,11 @@ static const struct vie_op one_byte_opcodes[256] = {
 	[0x23] = {
 		.op_byte = 0x23,
 		.op_type = VIE_OP_TYPE_AND,
+	},
+	[0x81] = {
+		.op_byte = 0x81,
+		.op_type = VIE_OP_TYPE_AND,
+		.op_flags = VIE_OP_F_IMM,
 	}
 };
 
@@ -299,6 +304,30 @@ emulate_and(void *vm, int vcpuid, uint64_t gpa, struct vie *vie,
 		val1 &= val2;
 		error = vie_update_register(vm, vcpuid, reg, val1, size);
 		break;
+	case 0x81:
+		printf("0x81 AND\n");
+		/*
+		 * AND reg (ModRM:reg) with immediate and store the
+		 * result in reg
+		 *
+		 * 81/          and r/m32, imm32
+		 * REX.W + 81/  and r/m64, imm32 sign-extended to 64
+		 */
+		if (vie->rex_w)
+			size = 8;
+		
+		/* get the first operand */
+                error = memread(vm, vcpuid, gpa, &val1, size, arg);
+                if (error)
+			break;
+
+                /*
+		 * perform the operation with the pre-fetched immediate
+		 * operand and write the result
+		 */
+                val1 &= vie->immediate;
+                error = memwrite(vm, vcpuid, gpa, val1, size, arg);
+		break;
 	default:
 		break;
 	}