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authorPeter Maydell <peter.maydell@linaro.org>2015-10-22 12:41:44 +0100
committerPeter Maydell <peter.maydell@linaro.org>2015-10-22 12:41:44 +0100
commitca3e40e233e87f7b29442311736a82da01c0df7b (patch)
treedba688d01dceded9b998e5d5cfb8cb9264354604 /docs/specs/vhost-user.txt
parentc1bd8997438f1b556acfeab1d52245ff7cc680c0 (diff)
parent3c23402d4032f69af44a87fdb8019ad3229a4f31 (diff)
Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
vhost, pc, virtio features, fixes, cleanups New features: VT-d support for devices behind a bridge vhost-user migration support Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Thu 22 Oct 2015 12:39:19 BST using RSA key ID D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" * remotes/mst/tags/for_upstream: (37 commits) hw/isa/lpc_ich9: inject the SMI on the VCPU that is writing to APM_CNT i386: keep cpu_model field in MachineState uptodate vhost: set the correct queue index in case of migration with multiqueue piix: fix resource leak reported by Coverity seccomp: add memfd_create to whitelist vhost-user-test: check ownership during migration vhost-user-test: add live-migration test vhost-user-test: learn to tweak various qemu arguments vhost-user-test: wrap server in TestServer struct vhost-user-test: remove useless static check vhost-user-test: move wait_for_fds() out vhost: add migration block if memfd failed vhost-user: use an enum helper for features mask vhost user: add rarp sending after live migration for legacy guest vhost user: add support of live migration net: add trace_vhost_user_event vhost-user: document migration log vhost: use a function for each call vhost-user: add a migration blocker vhost-user: send log shm fd along with log_base ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs/specs/vhost-user.txt')
-rw-r--r--docs/specs/vhost-user.txt63
1 files changed, 61 insertions, 2 deletions
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 4eadad1d6b..e0d71e27e6 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -115,11 +115,13 @@ the ones that do:
* VHOST_GET_FEATURES
* VHOST_GET_PROTOCOL_FEATURES
* VHOST_GET_VRING_BASE
+ * VHOST_SET_LOG_BASE (if VHOST_USER_PROTOCOL_F_LOG_SHMFD)
There are several messages that the master sends with file descriptors passed
in the ancillary data:
* VHOST_SET_MEM_TABLE
+ * VHOST_SET_LOG_BASE (if VHOST_USER_PROTOCOL_F_LOG_SHMFD)
* VHOST_SET_LOG_FD
* VHOST_SET_VRING_KICK
* VHOST_SET_VRING_CALL
@@ -140,8 +142,7 @@ Multiple queue support
Multiple queue is treated as a protocol extension, hence the slave has to
implement protocol features first. The multiple queues feature is supported
-only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set:
-#define VHOST_USER_PROTOCOL_F_MQ 0
+only when the protocol feature VHOST_USER_PROTOCOL_F_MQ (bit 0) is set.
The max number of queues the slave supports can be queried with message
VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of
@@ -152,6 +153,49 @@ queue in the sent message to identify a specified queue. One queue pair
is enabled initially. More queues are enabled dynamically, by sending
message VHOST_USER_SET_VRING_ENABLE.
+Migration
+---------
+
+During live migration, the master may need to track the modifications
+the slave makes to the memory mapped regions. The client should mark
+the dirty pages in a log. Once it complies to this logging, it may
+declare the VHOST_F_LOG_ALL vhost feature.
+
+All the modifications to memory pointed by vring "descriptor" should
+be marked. Modifications to "used" vring should be marked if
+VHOST_VRING_F_LOG is part of ring's features.
+
+Dirty pages are of size:
+#define VHOST_LOG_PAGE 0x1000
+
+The log memory fd is provided in the ancillary data of
+VHOST_USER_SET_LOG_BASE message when the slave has
+VHOST_USER_PROTOCOL_F_LOG_SHMFD protocol feature.
+
+The size of the log may be computed by using all the known guest
+addresses. The log covers from address 0 to the maximum of guest
+regions. In pseudo-code, to mark page at "addr" as dirty:
+
+page = addr / VHOST_LOG_PAGE
+log[page / 8] |= 1 << page % 8
+
+Use atomic operations, as the log may be concurrently manipulated.
+
+VHOST_USER_SET_LOG_FD is an optional message with an eventfd in
+ancillary data, it may be used to inform the master that the log has
+been modified.
+
+Once the source has finished migration, VHOST_USER_RESET_OWNER message
+will be sent by the source. No further update must be done before the
+destination takes over with new regions & rings.
+
+Protocol features
+-----------------
+
+#define VHOST_USER_PROTOCOL_F_MQ 0
+#define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
+#define VHOST_USER_PROTOCOL_F_RARP 2
+
Message types
-------------
@@ -236,6 +280,7 @@ Message types
Id: 6
Equivalent ioctl: VHOST_SET_LOG_BASE
Master payload: u64
+ Slave payload: N/A
Sets the logging base address.
@@ -337,3 +382,17 @@ Message types
Master payload: vring state description
Signal slave to enable or disable corresponding vring.
+
+ * VHOST_USER_SEND_RARP
+
+ Id: 19
+ Equivalent ioctl: N/A
+ Master payload: u64
+
+ Ask vhost user backend to broadcast a fake RARP to notify the migration
+ is terminated for guest that does not support GUEST_ANNOUNCE.
+ Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present in
+ VHOST_USER_GET_FEATURES and protocol feature bit VHOST_USER_PROTOCOL_F_RARP
+ is present in VHOST_USER_GET_PROTOCOL_FEATURES.
+ The first 6 bytes of the payload contain the mac address of the guest to
+ allow the vhost user backend to construct and broadcast the fake RARP.