From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Add MIG_RPCOMM_REQPAGES 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 | 3 ++
migration.c | 75 ++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 77 insertions(+), 1 deletion(-)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 67e5528..f53add7 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -45,6 +45,7 @@ struct MigrationParams {
enum mig_rpcomm_cmd {
MIG_RPCOMM_INVALID = 0, /* Must be 0 */
MIG_RPCOMM_ACK, /* data (seq: be32 ) */
+ MIG_RPCOMM_REQPAGES, /* data (start: be64, len: be64) */
MIG_RPCOMM_AFTERLASTVALID
};
@@ -234,6 +235,8 @@ void migrate_send_rp_message(MigrationIncomingState *mis,
uint16_t len, uint8_t *data);
void migrate_send_rp_ack(MigrationIncomingState *mis,
uint32_t value);
+void migrate_send_rp_reqpages(MigrationIncomingState *mis, const char* rbname,
+ ram_addr_t start, ram_addr_t len);
void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
diff --git a/migration.c b/migration.c
index c7ba6a1..efad18f 100644
--- a/migration.c
+++ b/migration.c
@@ -105,6 +105,38 @@ void migrate_send_rp_ack(MigrationIncomingState *mis,
migrate_send_rp_message(mis, MIG_RPCOMM_ACK, 4, (uint8_t *)&buf);
}
+/* 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_reqpages(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] = (uint64_t)start;
+ buf64[0] = cpu_to_be64(buf64[0]);
+ buf64[1] = (uint64_t)len;
+ buf64[1] = cpu_to_be64(buf64[1]);
+ migrate_send_rp_message(mis, MIG_RPCOMM_REQPAGES, msglen, bufc);
+}
+
void qemu_start_incoming_migration(const char *uri, Error **errp)
{
const char *p;
@@ -776,6 +808,17 @@ 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_reqpages(MigrationState *ms, const char* rbname,
+ ram_addr_t start, ram_addr_t len)
+{
+ DPRINTF("migrate_handle_rp_reqpages: at %zx for len %zx", start, len);
+}
+
+/*
* 'can read handler' for the fd callback
* stops the data handler being called if it's gone into
* error.
@@ -799,9 +842,12 @@ static void source_return_path_handler(void *opaque)
{
MigrationState *s = opaque;
QEMUFile *rp = qemu_file_get_return_path(s->file);
+ uint16_t expected_len;
const int max_len = 512;
uint8_t buf[max_len];
uint32_t tmp32;
+ uint64_t tmp64a, tmp64b;
+ char *tmpstr;
int res;
DPRINTF("RP: Receive\n");
@@ -811,7 +857,6 @@ static void source_return_path_handler(void *opaque)
}
if (s->rp_state.header_com == MIG_RPCOMM_INVALID) {
- uint16_t expected_len;
/* No command stored, so we're expecting a new header */
res = qemu_peek_buffer(rp, buf, 4, 0);
@@ -832,6 +877,11 @@ static void source_return_path_handler(void *opaque)
expected_len = 4;
break;
+ case MIG_RPCOMM_REQPAGES:
+ /* 16 byte start/len _possibly_ plus an id str */
+ expected_len = 16 + 256;
+ break;
+
default:
DPRINTF("RP: Received invalid cmd 0x%04x length 0x%04x\n",
s->rp_state.header_com, s->rp_state.header_len);
@@ -866,6 +916,29 @@ static void source_return_path_handler(void *opaque)
atomic_xchg(&s->rp_state.latest_ack, tmp32);
break;
+ case MIG_RPCOMM_REQPAGES:
+ tmp64a = be64_to_cpup((uint64_t *)buf); /* Start */
+ tmp64b = be64_to_cpup(((uint64_t *)buf)+1); /* Len */
+ tmpstr = NULL;
+ if (tmp64b & 1) {
+ /* 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 (s->rp_state.header_len != expected_len) {
+ error_report("RP: Received ReqPage with length %d expecting %d",
+ s->rp_state.header_len, expected_len);
+ source_return_path_bad(s);
+ }
+ migrate_handle_rp_reqpages(s, tmpstr,
+ (ram_addr_t)tmp64a,
+ (ram_addr_t)tmp64b);
+ break;
+
default:
/* This shouldn't happen because we should catch this above */
DPRINTF("RP: Bad header_com in dispatch\n");
--
1.9.3
