From c62b91e5804e7d2b1e8e253fc4031b4ea67a11f7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 9 Oct 2015 17:17:29 +0200 Subject: vhost-user: document migration log MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Marc-André Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Tested-by: Thibaut Collet --- docs/specs/vhost-user.txt | 48 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) (limited to 'docs/specs') diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index 4eadad1..e0292a0 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 +153,48 @@ 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 + Message types ------------- @@ -236,6 +279,7 @@ Message types Id: 6 Equivalent ioctl: VHOST_SET_LOG_BASE Master payload: u64 + Slave payload: N/A Sets the logging base address. -- cgit v1.1 From 3e866365e1eb6bcfa2d01c21debb05b9e47a47f7 Mon Sep 17 00:00:00 2001 From: Thibaut Collet Date: Fri, 9 Oct 2015 17:17:32 +0200 Subject: vhost user: add rarp sending after live migration for legacy guest MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A new vhost user message is added to allow QEMU to ask to vhost user backend to broadcast a fake RARP after live migration for guest without GUEST_ANNOUNCE capability. This new message is sent only if the backend supports the new VHOST_USER_PROTOCOL_F_RARP protocol feature. The payload of this new message is the MAC address of the guest (not known by the backend). The MAC address is copied in the first 6 bytes of a u64 to avoid to create a new payload message type. This new message has no equivalent ioctl so a new callback is added in the userOps structure to send the request. Upon reception of this new message the vhost user backend must generate and broadcast a fake RARP request to notify the migration is terminated. Signed-off-by: Thibaut Collet [Rebased and fixed checkpatch errors - Marc-André] Signed-off-by: Marc-André Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Tested-by: Thibaut Collet --- docs/specs/vhost-user.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'docs/specs') diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index e0292a0..e0d71e2 100644 --- a/docs/specs/vhost-user.txt +++ b/docs/specs/vhost-user.txt @@ -194,6 +194,7 @@ 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 ------------- @@ -381,3 +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. -- cgit v1.1