From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Add MIG_RP_MSG_REQ_PAGES command on Return path for the postcopy
destination to request a page from the source.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
include/migration/migration.h | 4 +++
migration/migration.c | 70 +++++++++++++++++++++++++++++++++++++++++++
trace-events | 1 +
3 files changed, 75 insertions(+)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 68a1731..8742d53 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -47,6 +47,8 @@ enum mig_rp_message_type {
MIG_RP_MSG_INVALID = 0, /* Must be 0 */
MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */
MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */
+
+ MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be64) */
};
typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
@@ -246,6 +248,8 @@ void migrate_send_rp_shut(MigrationIncomingState *mis,
uint32_t value);
void migrate_send_rp_pong(MigrationIncomingState *mis,
uint32_t value);
+void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char* rbname,
+ ram_addr_t start, ram_addr_t len);
void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
diff --git a/migration/migration.c b/migration/migration.c
index 3e5a7c8..0373b77 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -113,6 +113,36 @@ static void deferred_incoming_migration(Error **errp)
deferred_incoming = true;
}
+/* Request a range of pages from the source VM at the given
+ * start address.
+ * rbname: Name of the RAMBlock to request the page in, if NULL it's the same
+ * as the last request (a name must have been given previously)
+ * Start: Address offset within the RB
+ * Len: Length in bytes required - must be a multiple of pagesize
+ */
+void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname,
+ ram_addr_t start, ram_addr_t len)
+{
+ uint8_t bufc[16+1+255]; /* start (8 byte), len (8 byte), rbname upto 256 */
+ uint64_t *buf64 = (uint64_t *)bufc;
+ size_t msglen = 16; /* start + len */
+
+ assert(!(len & 1));
+ if (rbname) {
+ int rbname_len = strlen(rbname);
+ assert(rbname_len < 256);
+
+ len |= 1; /* Flag to say we've got a name */
+ bufc[msglen++] = rbname_len;
+ memcpy(bufc + msglen, rbname, rbname_len);
+ msglen += rbname_len;
+ }
+
+ buf64[0] = cpu_to_be64((uint64_t)start);
+ buf64[1] = cpu_to_be64((uint64_t)len);
+ migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc);
+}
+
void qemu_start_incoming_migration(const char *uri, Error **errp)
{
const char *p;
@@ -939,6 +969,17 @@ static void source_return_path_bad(MigrationState *s)
}
/*
+ * Process a request for pages received on the return path,
+ * We're allowed to send more than requested (e.g. to round to our page size)
+ * and we don't need to send pages that have already been sent.
+ */
+static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname,
+ ram_addr_t start, ram_addr_t len)
+{
+ trace_migrate_handle_rp_req_pages(rbname, start, len);
+}
+
+/*
* Handles messages sent on the return path towards the source VM
*
*/
@@ -950,6 +991,8 @@ static void *source_return_path_thread(void *opaque)
const int max_len = 512;
uint8_t buf[max_len];
uint32_t tmp32;
+ ram_addr_t start, len;
+ char *tmpstr;
int res;
trace_source_return_path_thread_entry();
@@ -965,6 +1008,11 @@ static void *source_return_path_thread(void *opaque)
expected_len = 4;
break;
+ case MIG_RP_MSG_REQ_PAGES:
+ /* 16 byte start/len _possibly_ plus an id str */
+ expected_len = 16 + 256;
+ break;
+
default:
error_report("RP: Received invalid message 0x%04x length 0x%04x",
header_type, header_len);
@@ -1010,6 +1058,28 @@ static void *source_return_path_thread(void *opaque)
trace_source_return_path_thread_pong(tmp32);
break;
+ case MIG_RP_MSG_REQ_PAGES:
+ start = be64_to_cpup((uint64_t *)buf);
+ len = be64_to_cpup(((uint64_t *)buf)+1);
+ tmpstr = NULL;
+ if (len & 1) {
+ len -= 1; /* Remove the flag */
+ /* Now we expect an idstr */
+ tmp32 = buf[16]; /* Length of the following idstr */
+ tmpstr = (char *)&buf[17];
+ buf[17+tmp32] = '\0';
+ expected_len = 16+1+tmp32;
+ } else {
+ expected_len = 16;
+ }
+ if (header_len != expected_len) {
+ error_report("RP: Req_Page with length %d expecting %d",
+ header_len, expected_len);
+ source_return_path_bad(ms);
+ }
+ migrate_handle_rp_req_pages(ms, tmpstr, start, len);
+ break;
+
default:
break;
}
diff --git a/trace-events b/trace-events
index 528d5a3..328d64c 100644
--- a/trace-events
+++ b/trace-events
@@ -1422,6 +1422,7 @@ migrate_fd_error(void) ""
migrate_fd_cancel(void) ""
migrate_pending(uint64_t size, uint64_t max, uint64_t post, uint64_t nonpost)
"pending size %" PRIu64 " max %" PRIu64 " (post=%" PRIu64 " nonpost=%" PRIu64
")"
migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
+migrate_handle_rp_req_pages(const char *rbname, size_t start, size_t len) "in
%s at %zx len %zx"
migration_thread_after_loop(void) ""
migration_thread_file_err(void) ""
migration_thread_setup_complete(void) ""
--
2.4.3
