Hi ----- Original Message ----- > On Thu, Jul 23, 2015 at 03:36:43AM +0200, Marc-André Lureau wrote: > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > > for some reason I didn't get 5/6. >
strange: http://lists.nongnu.org/archive/html/qemu-devel/2015-07/msg04640.html > > --- > > docs/specs/vhost-user.txt | 40 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 40 insertions(+) > > > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt > > index 0062baa..c2d2e2a 100644 > > --- a/docs/specs/vhost-user.txt > > +++ b/docs/specs/vhost-user.txt > > @@ -120,6 +120,7 @@ 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 > > @@ -135,6 +136,11 @@ As older slaves don't support negotiating protocol > > features, > > a feature bit was dedicated for this purpose: > > #define VHOST_USER_F_PROTOCOL_FEATURES 30 > > > > +Protocol features > > +----------------- > > + > > +#define VHOST_USER_PROTOCOL_F_LOG_SHMFD 0 > > + > > Message types > > ------------- > > > > @@ -301,3 +307,37 @@ Message types > > Bits (0-7) of the payload contain the vring index. Bit 8 is the > > invalid FD flag. This flag is set when there is no file descriptor > > in the ancillary data. > > + > > +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 VHOST_F_LOG_ALL has a 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. > > It's device's features I think. Hmm, it's part of both, not sure why: see vhost_virtqueue_set_addr() and vhost_dev_set_features() Not sure it's correct in device features, it doesn't seem to be check in kernel vhost.c either. There is also some dead definitions like VHOST_MEMORY_F_LOG there > > > + > > +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 > > Pls note it must be done atomically. ok > > > > + > > +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. > > -- > > 2.4.3 >
