einj_mem_uc: add extra arguments to support guest error injection

To support Guest Error injection, add two extra arguments:

- '-j': skip error injection, this step should do with host physical
  address on host which creates GPA->HPA mappings for the guest.
- '-k': kick off trigger by writing a file from remote (host).

The steps to inject guest error are:

STEP 1: start a VM with a stdio monitor which allows giving complex
commands to the QEMU emulator.

	qemu-system-aarch64  -enable-kvm \
		-cpu host \
		-M virt,gic-version=3 \
		-m 8G \
		-d guest_errors \
		-rtc base=localtime,clock=host \
		-smp cores=2,threads=2,sockets=2 \
		-object memory-backend-ram,id=mem0,size=4G \
		-object memory-backend-ram,id=mem1,size=4G \
		-numa node,memdev=mem0,cpus=0-3,nodeid=0 \
		-numa node,memdev=mem1,cpus=4-7,nodeid=1 \
		-bios /usr/share/AAVMF/AAVMF_CODE.fd \
		-drive driver=qcow2,media=disk,cache=writeback,if=virtio,id=alinu1_rootfs,file=/path/to/image.qcow2 \
		-netdev user,id=n1,hostfwd=tcp::5555-:22  \
		-serial telnet:localhost:4321,server,nowait \
		-device virtio-net-pci,netdev=n1 \
		-monitor stdio
	QEMU 7.2.0 monitor - type 'help' for more information
	(qemu) VNC server running on 127.0.0.1:5900

STEP 2: login guest and install ras-tools, then run `einj_mem_uc` to
allocate a page in userspace, dumps the virtual and physical address of the
page. The `-j` is to skip error injection and `-k` is to wait for a kick.

	$ ./einj_mem_uc single -j -k
	0: single   vaddr = 0xffffbd88c400 paddr = 151f21400

STEP 3: run command `gpa2hpa` in QEMU monitor and it will print the host
physical address at which the guest's physical address addr is mapped.

	(qemu) gpa2hpa 0x151f21400
	Host physical address for 0x151f21400 (mem1) is 0x935757400

STEP 4: inject an uncorrected error via the APEI interface to the finally
translated host physical address on host.

	echo 0x949a84400 > /sys/kernel/debug/apei/einj/param1
	echo 0xfffffffffffff000 > /sys/kernel/debug/apei/einj/param2
	echo 0x0 > /sys/kernel/debug/apei/einj/flags
	echo 0x10 > /sys/kernel/debug/apei/einj/error_type
	echo 1 > /sys/kernel/debug/apei/einj/notrigger
	echo 1 > /sys/kernel/debug/apei/einj/error_inject

STEP 5: then kick `einj_mem_uc` to trigger the error by writing
"trigger_start".  In this example, the kick is done on host.

	ssh -p 5555 root@localhost "echo trigger > ~/trigger_start"

STEP 6: We will observe that the QEMU process exit.

	(qemu) qemu-system-aarch64: Hardware memory error!

Signed-off-by: zhangyangzeyu.zyzy <xiaoque@linux.alibaba.com>
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 117 insertions, 6 deletions

diff --git a/README b/README
index da17edd..a896ab9 100644
--- a/README
+++ b/README
@@ -19,3 +19,74 @@ Arm platform specific drivers:
 
 - memattr: a test suit to poison specific memory attribute.
 - ras-tolerance: a driver to overwrite error severity to a lower level at runtime.
+
+Virtualization:
+
+Injecting errors into guests is a rather manual process. You can run einj_mem_uc
+inside the guest with special arguments to skip the injection, but still print
+the guest physical address. Then on the host convert that to a host physical
+address and inject. Finally have the process on the guest consume the error.
+
+Detailed steps are:
+
+- '-j': skip error injection, this step should do with host physical
+  address on host which creates GPA->HPA mappings for the guest.
+- '-k': kick off trigger by writing a file from remote (host).
+
+The steps to inject guest error are:
+
+STEP 1: start a VM with a stdio monitor which allows giving complex
+commands to the QEMU emulator.
+
+        qemu-system-aarch64  -enable-kvm \
+                -cpu host \
+                -M virt,gic-version=3 \
+                -m 8G \
+                -d guest_errors \
+                -rtc base=localtime,clock=host \
+                -smp cores=2,threads=2,sockets=2 \
+                -object memory-backend-ram,id=mem0,size=4G \
+                -object memory-backend-ram,id=mem1,size=4G \
+                -numa node,memdev=mem0,cpus=0-3,nodeid=0 \
+                -numa node,memdev=mem1,cpus=4-7,nodeid=1 \
+                -bios /usr/share/AAVMF/AAVMF_CODE.fd \
+                -drive driver=qcow2,media=disk,cache=writeback,if=virtio,id=alinu1_rootfs,file=/path/to/image.qcow2 \
+                -netdev user,id=n1,hostfwd=tcp::5555-:22  \
+                -serial telnet:localhost:4321,server,nowait \
+                -device virtio-net-pci,netdev=n1 \
+                -monitor stdio
+        QEMU 7.2.0 monitor - type 'help' for more information
+        (qemu) VNC server running on 127.0.0.1:5900
+
+STEP 2: login guest and install ras-tools, then run `einj_mem_uc` to
+allocate a page in userspace, dumps the virtual and physical address of the
+page. The `-j` is to skip error injection and `-k` is to wait for a kick.
+
+        $ ./einj_mem_uc single -j -k
+        0: single   vaddr = 0xffffbd88c400 paddr = 151f21400
+
+STEP 3: run command `gpa2hpa` in QEMU monitor and it will print the host
+physical address at which the guest's physical address addr is mapped.
+
+        (qemu) gpa2hpa 0x151f21400
+        Host physical address for 0x151f21400 (mem1) is 0x935757400
+
+STEP 4: inject an uncorrected error via the APEI interface to the finally
+translated host physical address on host.
+
+        echo 0x949a84400 > /sys/kernel/debug/apei/einj/param1
+        echo 0xfffffffffffff000 > /sys/kernel/debug/apei/einj/param2
+        echo 0x0 > /sys/kernel/debug/apei/einj/flags
+        echo 0x10 > /sys/kernel/debug/apei/einj/error_type
+        echo 1 > /sys/kernel/debug/apei/einj/notrigger
+        echo 1 > /sys/kernel/debug/apei/einj/error_inject
+
+STEP 5: then kick `einj_mem_uc` to trigger the error by writing
+"trigger_start".  In this example, the kick is done on host.
+
+        ssh -p 5555 root@localhost "echo trigger > ~/trigger_start"
+
+STEP 6: We will observe that the QEMU process exit.
+
+        (qemu) qemu-system-aarch64: Hardware memory error!
+
diff --git a/einj_mem_uc.c b/einj_mem_uc.c
index acc64fd..88764d0 100644
--- a/einj_mem_uc.c
+++ b/einj_mem_uc.c
@@ -1057,7 +1057,7 @@ static void show_help(void)
 {
 	struct test *t;
 
-	printf("Usage: %s [-a][-c count][-d delay][-f][-i] [-m runup:size:align][testname]\n", progname);
+	printf("Usage: %s [-a][-c count][-d delay][-f][-i][j][k] [-m runup:size:align][testname]\n", progname);
 	printf("  %-8s %-5s %s\n", "Testname", "Fatal", "Description");
 	for (t = tests; t->testname; t++)
 		printf("  %-8s %-5s %s\n", t->testname,
@@ -1098,10 +1098,40 @@ struct sigaction recover_act = {
 	.sa_flags = SA_SIGINFO,
 };
 
+void kick_by_file(struct test *t, char *addr) {
+	const char *trigger = "./trigger_start";
+	const char *trigger_flag = "trigger";
+	char trigger_buf[16];
+	int count = 64*3;
+	int fd;
+	errno = 0;
+
+	if (unlink(trigger) < 0 && errno != ENOENT) {
+		fprintf(stderr, "fail to remove trigger file\n");
+		exit(1);
+	}
+
+	memset(trigger_buf, 0, sizeof(trigger_buf));
+	while (count--) {
+		if ((fd = open(trigger, O_RDONLY)) < 0) {
+			sleep(1);
+			continue;
+		}
+		if (read(fd, trigger_buf, sizeof(trigger_buf)) > 0 &&
+			strstr(trigger_buf, trigger_flag) != NULL) {
+			break;
+		}
+		sleep(1);
+	}
+
+	/* trigger now */
+	t->trigger(addr);
+}
+
 int main(int argc, char **argv)
 {
 	int c, i;
-	int	count = 1;
+	int	count = 1, kick = 0, inject_skip_flag = 0;
 	double	delay = 1.0;
 	struct test *t;
 	void	*vaddr;
@@ -1118,7 +1148,7 @@ int main(int argc, char **argv)
 	pagesize = getpagesize();
 	pid = getpid();
 
-	while ((c = getopt(argc, argv, "ac:d:fhim:z:S")) != -1) switch (c) {
+	while ((c = getopt(argc, argv, "ac:d:fhijkm:z:S")) != -1) switch (c) {
 	case 'a':
 		all_flag = 1;
 		break;
@@ -1134,6 +1164,12 @@ int main(int argc, char **argv)
 	case 'i':
 		cmci_skip_flag = 1;
 		break;
+	case 'j':
+		inject_skip_flag = 1;
+		break;
+	case 'k':
+		kick = 1;
+		break;
 	case 'm':
 		parse_memcpy(optarg);
 		break;
@@ -1148,7 +1184,7 @@ int main(int argc, char **argv)
 		break;
 	}
 
-	if (Sflag == 0)
+	if (Sflag == 0 && inject_skip_flag == 0)
 		check_configuration();
 
 	if (optind < argc)
@@ -1178,9 +1214,13 @@ int main(int argc, char **argv)
 				printf("Unexpected SIGBUS\n");
 			}
 		} else {
-			t->inject(paddr, vaddr, t->notrigger);
+			if (!inject_skip_flag)
+				t->inject(paddr, vaddr, t->notrigger);
 			sleep(3);
-			t->trigger(vaddr);
+			if (kick)
+				kick_by_file(t, vaddr);
+			else
+				t->trigger(vaddr);
 			if (t->flags & F_SIGBUS) {
 				printf("Expected SIGBUS, didn't get one\n");
 			}