kvm: decode KVM_EXIT_MMIO related fields of kvm_run struct

* src/kvm.c (kvm_run_structure_decode_mmio): New function.
(kvm_run_structure_decode_main) <case KVM_EXIT_MMIO>: Decode the area
of kvm_run struct.
* tests/ioctl_kvm_run_common.c (__asm__): Add the instructions
accessing address where no memory backing store to code.
(run_kvm): Raise an error only when getting unexpected MMIO exit.
* tests/ioctl_kvm_run_auxstr_vcpu_more.c (print_KVM_RUN_MORE): Print
mmio members of kvm_run struct.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

Author: masatake

src/kvm.c

@@ -465,6 +465,22 @@ kvm_run_structure_decode_io(struct tcb *tcp,
 	tprint_struct_end();
 }
 
+static void
+kvm_run_structure_decode_mmio(struct tcb *tcp,
+			      struct kvm_run *state)
+{
+	tprints_field_name("mmio");
+	tprint_struct_begin();
+	PRINT_FIELD_0X(state->mmio, phys_addr);
+	tprint_struct_next();
+	PRINT_FIELD_ARRAY(state->mmio, data, tcp, print_xint_array_member);
+	tprint_struct_next();
+	PRINT_FIELD_U(state->mmio, len);
+	tprint_struct_next();
+	PRINT_FIELD_U(state->mmio, is_write);
+	tprint_struct_end();
+}
+
 static void
 kvm_run_structure_decode_main(struct tcb *tcp,
 			      struct kvm_run *state_in,
@@ -522,6 +538,9 @@ kvm_run_structure_decode_main(struct tcb *tcp,
 	case KVM_EXIT_IO:
 		DECODE_UNION(kvm_run_structure_decode_io(tcp, state_out));
 		break;
+	case KVM_EXIT_MMIO:
+		DECODE_UNION(kvm_run_structure_decode_mmio(tcp, state_out));
+		break;
 	}
 
 	tprint_struct_end();

tests/ioctl_kvm_run_auxstr_vcpu_more.c

@@ -32,6 +32,16 @@ print_KVM_RUN_MORE(const int fd, const char *const dev, const char *str,
 		       run_after->io.direction == KVM_EXIT_IO_IN? "KVM_EXIT_IO_IN": "KVM_EXIT_IO_OUT",
 		       run_after->io.port, run_after->io.count, run_after->io.data_offset);
 		break;
+	case KVM_EXIT_MMIO:
+		printf(", {mmio={phys_addr=%#016llx, data=[%#0x, %#0x, %#0x, %#0x, %#0x, %#0x, %#0x, %#0x], len=%u, is_write=%u}}",
+		       run_after->mmio.phys_addr,
+		       run_after->mmio.data[0], run_after->mmio.data[1],
+		       run_after->mmio.data[2], run_after->mmio.data[3],
+		       run_after->mmio.data[4], run_after->mmio.data[5],
+		       run_after->mmio.data[6], run_after->mmio.data[7],
+		       run_after->mmio.len,
+		       run_after->mmio.is_write);
+		break;
 	}
 
 	puts("}");

tests/ioctl_kvm_run_common.c

@@ -80,6 +80,8 @@ __asm__(
 	"	mov $0x03f8, %dx	\n"
 	"	movb $'\n', %al		\n"
 	"	out %al, (%dx)		\n"
+	"	mov $0x2000, %dx	\n"
+	"	movb $0xdf, (%edx)	\n"
 	"	hlt			\n"
 # ifdef __x86_64__
 	".code64			\n"
@@ -91,6 +93,11 @@ __asm__(
 	"code_size:			\n"
 	"	.short . - code		\n"
 	".size code_size, . - code_size	\n"
+#ifdef __x86_64__
+	".code64			\n"
+#else
+	".code32			\n"
+#endif
 	);
 
 static void
@@ -237,17 +244,23 @@ run_kvm(const int vcpu_fd, struct kvm_run *const run, const size_t mmap_size,
 				error_msg_and_fail("unhandled KVM_EXIT_IO");
 			break;
 		case KVM_EXIT_MMIO:
-			error_msg_and_fail("Got an unexpected MMIO exit:"
-					   " phys_addr %#llx,"
-					   " data %02x %02x %02x %02x"
-						" %02x %02x %02x %02x,"
-					   " len %u, is_write %hhu",
-					   (unsigned long long) run->mmio.phys_addr,
-					   run->mmio.data[0], run->mmio.data[1],
-					   run->mmio.data[2], run->mmio.data[3],
-					   run->mmio.data[4], run->mmio.data[5],
-					   run->mmio.data[6], run->mmio.data[7],
-					   run->mmio.len, run->mmio.is_write);
+			if (!(p == NULL
+			      && run->mmio.phys_addr == 0x2000
+			      && run->mmio.data[0] == 0xdf
+			      && run->mmio.len == 1
+			      && run->mmio.is_write == 1))
+				error_msg_and_fail("Got an unexpected MMIO exit:"
+						   " phys_addr %#llx,"
+						   " data %02x %02x %02x %02x"
+						   " %02x %02x %02x %02x,"
+						   " len %u, is_write %hhu\n",
+						   (unsigned long long) run->mmio.phys_addr,
+						   run->mmio.data[0], run->mmio.data[1],
+						   run->mmio.data[2], run->mmio.data[3],
+						   run->mmio.data[4], run->mmio.data[5],
+						   run->mmio.data[6], run->mmio.data[7],
+						   run->mmio.len, run->mmio.is_write);
+			break;
 		case KVM_EXIT_FAIL_ENTRY:
 			error_msg_and_fail("Got an unexpected FAIL_ENTRY exit:"
 					   " hardware_entry_failure_reason %" PRI__x64,