From: zhanghailiang <zhang.zhanghaili...@huawei.com>
We can get guest's memory block information by using command
"guest-get-memory-blocks", the returned value contains a list of memory block
info, such as phys-index, online state, can-offline info.
Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
*replaced guest-triggerable assertion with an error msg
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
qga/commands-posix.c | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 233 insertions(+), 1 deletion(-)
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 0ce27a4..6cd21b2 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -1992,9 +1992,241 @@ out:
}
}
+static void ga_read_sysfs_file(int dirfd, const char *pathname, char *buf,
+ int size, Error **errp)
+{
+ int fd;
+ int res;
+
+ errno = 0;
+ fd = openat(dirfd, pathname, O_RDONLY);
+ if (fd == -1) {
+ error_setg_errno(errp, errno, "open sysfs file \"%s\"", pathname);
+ return;
+ }
+
+ res = pread(fd, buf, size, 0);
+ if (res == -1) {
+ error_setg_errno(errp, errno, "pread sysfs file \"%s\"", pathname);
+ } else if (res == 0) {
+ error_setg(errp, "pread sysfs file \"%s\": unexpected EOF", pathname);
+ }
+ close(fd);
+}
+
+static void ga_write_sysfs_file(int dirfd, const char *pathname,
+ const char *buf, int size, Error **errp)
+{
+ int fd;
+
+ errno = 0;
+ fd = openat(dirfd, pathname, O_WRONLY);
+ if (fd == -1) {
+ error_setg_errno(errp, errno, "open sysfs file \"%s\"", pathname);
+ return;
+ }
+
+ if (pwrite(fd, buf, size, 0) == -1) {
+ error_setg_errno(errp, errno, "pwrite sysfs file \"%s\"", pathname);
+ }
+
+ close(fd);
+}
+
+/* Transfer online/offline status between @mem_blk and the guest system.
+ *
+ * On input either @errp or *@errp must be NULL.
+ *
+ * In system-to-@mem_blk direction, the following @mem_blk fields are accessed:
+ * - R: mem_blk->phys_index
+ * - W: mem_blk->online
+ * - W: mem_blk->can_offline
+ *
+ * In @mem_blk-to-system direction, the following @mem_blk fields are accessed:
+ * - R: mem_blk->phys_index
+ * - R: mem_blk->online
+ *- R: mem_blk->can_offline
+ * Written members remain unmodified on error.
+ */
+static void transfer_memory_block(GuestMemoryBlock *mem_blk, bool sys2memblk,
+ GuestMemoryBlockResponse *result,
+ Error **errp)
+{
+ char *dirpath;
+ int dirfd;
+ char *status;
+ Error *local_err = NULL;
+
+ if (!sys2memblk) {
+ DIR *dp;
+
+ if (!result) {
+ error_setg(errp, "Internal error, 'result' should not be NULL");
+ return;
+ }
+ errno = 0;
+ dp = opendir("/sys/devices/system/memory/");
+ /* if there is no 'memory' directory in sysfs,
+ * we think this VM does not support online/offline memory block,
+ * any other solution?
+ */
+ if (!dp && errno == ENOENT) {
+ result->response =
+ GUEST_MEMORY_BLOCK_RESPONSE_TYPE_OPERATION_NOT_SUPPORTED;
+ goto out1;
+ }
+ closedir(dp);
+ }
+
+ dirpath = g_strdup_printf("/sys/devices/system/memory/memory%" PRId64 "/",
+ mem_blk->phys_index);
+ dirfd = open(dirpath, O_RDONLY | O_DIRECTORY);
+ if (dirfd == -1) {
+ if (sys2memblk) {
+ error_setg_errno(errp, errno, "open(\"%s\")", dirpath);
+ } else {
+ if (errno == ENOENT) {
+ result->response = GUEST_MEMORY_BLOCK_RESPONSE_TYPE_NOT_FOUND;
+ } else {
+ result->response =
+ GUEST_MEMORY_BLOCK_RESPONSE_TYPE_OPERATION_FAILED;
+ }
+ }
+ g_free(dirpath);
+ goto out1;
+ }
+ g_free(dirpath);
+
+ status = g_malloc0(10);
+ ga_read_sysfs_file(dirfd, "state", status, 10, &local_err);
+ if (local_err) {
+ /* treat with sysfs file that not exist in old kernel */
+ if (errno == ENOENT) {
+ error_free(local_err);
+ if (sys2memblk) {
+ mem_blk->online = true;
+ mem_blk->can_offline = false;
+ } else if (!mem_blk->online) {
+ result->response =
+ GUEST_MEMORY_BLOCK_RESPONSE_TYPE_OPERATION_NOT_SUPPORTED;
+ }
+ } else {
+ if (sys2memblk) {
+ error_propagate(errp, local_err);
+ } else {
+ result->response =
+ GUEST_MEMORY_BLOCK_RESPONSE_TYPE_OPERATION_FAILED;
+ }
+ }
+ goto out2;
+ }
+
+ if (sys2memblk) {
+ char removable = '0';
+
+ mem_blk->online = (strncmp(status, "online", 6) == 0);
+
+ ga_read_sysfs_file(dirfd, "removable", &removable, 1, &local_err);
+ if (local_err) {
+ /* if no 'removable' file, it does't support offline mem blk */
+ if (errno == ENOENT) {
+ error_free(local_err);
+ mem_blk->can_offline = false;
+ } else {
+ error_propagate(errp, local_err);
+ }
+ } else {
+ mem_blk->can_offline = (removable != '0');
+ }
+ } else {
+ if (mem_blk->online != (strncmp(status, "online", 6) == 0)) {
+ char *new_state = mem_blk->online ? g_strdup("online") :
+ g_strdup("offline");
+
+ ga_write_sysfs_file(dirfd, "state", new_state, strlen(new_state),
+ &local_err);
+ g_free(new_state);
+ if (local_err) {
+ error_free(local_err);
+ result->response =
+ GUEST_MEMORY_BLOCK_RESPONSE_TYPE_OPERATION_FAILED;
+ goto out2;
+ }
+
+ result->response = GUEST_MEMORY_BLOCK_RESPONSE_TYPE_SUCCESS;
+ result->has_error_code = false;
+ } /* otherwise pretend successful re-(on|off)-lining */
+ }
+ g_free(status);
+ close(dirfd);
+ return;
+
+out2:
+ g_free(status);
+ close(dirfd);
+out1:
+ if (!sys2memblk) {
+ result->has_error_code = true;
+ result->error_code = errno;
+ }
+}
+
GuestMemoryBlockList *qmp_guest_get_memory_blocks(Error **errp)
{
- error_set(errp, QERR_UNSUPPORTED);
+ GuestMemoryBlockList *head, **link;
+ Error *local_err = NULL;
+ struct dirent *de;
+ DIR *dp;
+
+ head = NULL;
+ link = &head;
+
+ dp = opendir("/sys/devices/system/memory/");
+ if (!dp) {
+ error_setg_errno(errp, errno, "Can't open directory"
+ "\"/sys/devices/system/memory/\"\n");
+ return NULL;
+ }
+
+ /* Note: the phys_index of memory block may be discontinuous,
+ * this is because a memblk is the unit of the Sparse Memory design, which
+ * allows discontinuous memory ranges (ex. NUMA), so here we should
+ * traverse the memory block directory.
+ */
+ while ((de = readdir(dp)) != NULL) {
+ GuestMemoryBlock *mem_blk;
+ GuestMemoryBlockList *entry;
+
+ if ((strncmp(de->d_name, "memory", 6) != 0) ||
+ !(de->d_type & DT_DIR)) {
+ continue;
+ }
+
+ mem_blk = g_malloc0(sizeof *mem_blk);
+ /* The d_name is "memoryXXX", phys_index is block id, same as XXX */
+ mem_blk->phys_index = strtoul(&de->d_name[6], NULL, 10);
+ mem_blk->has_can_offline = true; /* lolspeak ftw */
+ transfer_memory_block(mem_blk, true, NULL, &local_err);
+
+ entry = g_malloc0(sizeof *entry);
+ entry->value = mem_blk;
+
+ *link = entry;
+ link = &entry->next;
+ }
+
+ closedir(dp);
+ if (local_err == NULL) {
+ /* there's no guest with zero memory blocks */
+ if (head == NULL) {
+ error_setg(errp, "guest reported zero memory blocks!");
+ return;
+ }
+ return head;
+ }
+
+ qapi_free_GuestMemoryBlockList(head);
+ error_propagate(errp, local_err);
return NULL;
}
--
1.9.1
