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Re: [Qemu-devel] [PATCH v4 06/29] vhost-user: Add 'VHOST_USER_POSTCOPY_A
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v4 06/29] vhost-user: Add 'VHOST_USER_POSTCOPY_ADVISE' message |
Date: |
Mon, 12 Mar 2018 14:02:51 +0000 |
User-agent: |
Mutt/1.9.2 (2017-12-15) |
* Marc-André Lureau (address@hidden) wrote:
> Hi
>
> On Thu, Mar 8, 2018 at 8:57 PM, Dr. David Alan Gilbert (git)
> <address@hidden> wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Wire up a notifier to send a VHOST_USER_POSTCOPY_ADVISE
> > message on an incoming advise.
> >
> > Later patches will fill in the behaviour/contents of the
> > message.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > Reviewed-by: Marc-André Lureau <address@hidden>
> > ---
> > contrib/libvhost-user/libvhost-user.c | 14 ++++++++++
> > contrib/libvhost-user/libvhost-user.h | 3 +++
> > docs/interop/vhost-user.txt | 10 ++++++++
> > hw/virtio/vhost-user.c | 48
> > +++++++++++++++++++++++++++++++++++
> > migration/postcopy-ram.h | 1 +
> > migration/savevm.c | 6 +++++
> > 6 files changed, 82 insertions(+)
> >
> > diff --git a/contrib/libvhost-user/libvhost-user.c
> > b/contrib/libvhost-user/libvhost-user.c
> > index 2e358b5bce..71825d2dde 100644
> > --- a/contrib/libvhost-user/libvhost-user.c
> > +++ b/contrib/libvhost-user/libvhost-user.c
> > @@ -86,6 +86,7 @@ vu_request_to_string(unsigned int req)
> > REQ(VHOST_USER_SET_VRING_ENDIAN),
> > REQ(VHOST_USER_GET_CONFIG),
> > REQ(VHOST_USER_SET_CONFIG),
> > + REQ(VHOST_USER_POSTCOPY_ADVISE),
> > REQ(VHOST_USER_MAX),
> > };
> > #undef REQ
> > @@ -856,6 +857,17 @@ vu_set_config(VuDev *dev, VhostUserMsg *vmsg)
> > return false;
> > }
> >
> > +static bool
> > +vu_set_postcopy_advise(VuDev *dev, VhostUserMsg *vmsg)
> > +{
> > + /* TODO: Open ufd, pass it back in the request
> > + * TODO: Add addresses
> > + */
> > + vmsg->payload.u64 = 0xcafe;
> > + vmsg->size = sizeof(vmsg->payload.u64);
>
> Left over? Why send back a u64 with 0xcafe value?
I think because I didn't realise it could be an empty reply; OK, v5
coming up with that removed once we're done with this set.
> > + return true; /* = send a reply */
> > +}
> > +
> > static bool
> > vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
> > {
> > @@ -927,6 +939,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
> > return vu_set_config(dev, vmsg);
> > case VHOST_USER_NONE:
> > break;
> > + case VHOST_USER_POSTCOPY_ADVISE:
> > + return vu_set_postcopy_advise(dev, vmsg);
> > default:
> > vmsg_close_fds(vmsg);
> > vu_panic(dev, "Unhandled request: %d", vmsg->request);
> > diff --git a/contrib/libvhost-user/libvhost-user.h
> > b/contrib/libvhost-user/libvhost-user.h
> > index 96db29c4ce..00d78a8810 100644
> > --- a/contrib/libvhost-user/libvhost-user.h
> > +++ b/contrib/libvhost-user/libvhost-user.h
> > @@ -83,6 +83,9 @@ typedef enum VhostUserRequest {
> > VHOST_USER_SET_VRING_ENDIAN = 23,
> > VHOST_USER_GET_CONFIG = 24,
> > VHOST_USER_SET_CONFIG = 25,
> > + VHOST_USER_CREATE_CRYPTO_SESSION = 26,
> > + VHOST_USER_CLOSE_CRYPTO_SESSION = 27,
> > + VHOST_USER_POSTCOPY_ADVISE = 28,
> > VHOST_USER_MAX
> > } VhostUserRequest;
> >
> > diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
> > index 91a572d781..acc4186c79 100644
> > --- a/docs/interop/vhost-user.txt
> > +++ b/docs/interop/vhost-user.txt
> > @@ -699,6 +699,16 @@ Master message types
> > feature has been successfully negotiated.
> > It's a required feature for crypto devices.
> >
> > + * VHOST_USER_POSTCOPY_ADVISE
> > + Id: 28
> > + Master payload: N/A
> > + Slave payload: userfault fd + u64
>
> If the reply is modified, update doc as well
>
> > +
> > + When VHOST_USER_PROTOCOL_F_PAGEFAULT is supported, the
> > + master advises slave that a migration with postcopy enabled is
> > underway,
> > + the slave must open a userfaultfd for later use.
> > + Note that at this stage the migration is still in precopy mode.
> > +
> > Slave message types
> > -------------------
> >
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index aab35c4845..431858b219 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -78,6 +78,7 @@ typedef enum VhostUserRequest {
> > VHOST_USER_SET_CONFIG = 25,
> > VHOST_USER_CREATE_CRYPTO_SESSION = 26,
> > VHOST_USER_CLOSE_CRYPTO_SESSION = 27,
> > + VHOST_USER_POSTCOPY_ADVISE = 28,
> > VHOST_USER_MAX
> > } VhostUserRequest;
> >
> > @@ -795,6 +796,50 @@ out:
> > return ret;
> > }
> >
> > +/*
> > + * Called at the start of an inbound postcopy on reception of the
> > + * 'advise' command.
> > + */
> > +static int vhost_user_postcopy_advise(struct vhost_dev *dev, Error **errp)
> > +{
> > + struct vhost_user *u = dev->opaque;
> > + CharBackend *chr = u->chr;
> > + int ufd;
> > + VhostUserMsg msg = {
> > + .hdr.request = VHOST_USER_POSTCOPY_ADVISE,
> > + .hdr.flags = VHOST_USER_VERSION,
> > + };
> > +
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + error_setg(errp, "Failed to send postcopy_advise to vhost");
> > + return -1;
> > + }
> > +
> > + if (vhost_user_read(dev, &msg) < 0) {
> > + error_setg(errp, "Failed to get postcopy_advise reply from vhost");
> > + return -1;
> > + }
> > +
> > + if (msg.hdr.request != VHOST_USER_POSTCOPY_ADVISE) {
> > + error_setg(errp, "Unexpected msg type. Expected %d received %d",
> > + VHOST_USER_POSTCOPY_ADVISE, msg.hdr.request);
> > + return -1;
> > + }
> > +
> > + if (msg.hdr.size != sizeof(msg.payload.u64)) {
> > + error_setg(errp, "Received bad msg size.");
> > + return -1;
> > + }
> > + ufd = qemu_chr_fe_get_msgfd(chr);
> > + if (ufd < 0) {
> > + error_setg(errp, "%s: Failed to get ufd", __func__);
> > + return -1;
> > + }
> > +
> > + /* TODO: register ufd with userfault thread */
> > + return 0;
> > +}
> > +
> > static int vhost_user_postcopy_notifier(NotifierWithReturn *notifier,
> > void *opaque)
> > {
> > @@ -814,6 +859,9 @@ static int
> > vhost_user_postcopy_notifier(NotifierWithReturn *notifier,
> > }
> > break;
> >
> > + case POSTCOPY_NOTIFY_INBOUND_ADVISE:
> > + return vhost_user_postcopy_advise(dev, pnd->errp);
> > +
> > default:
> > /* We ignore notifications we don't know */
> > break;
> > diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h
> > index 2e879bbacb..0421c98d57 100644
> > --- a/migration/postcopy-ram.h
> > +++ b/migration/postcopy-ram.h
> > @@ -130,6 +130,7 @@ void postcopy_infrastructure_init(void);
> > */
> > enum PostcopyNotifyReason {
> > POSTCOPY_NOTIFY_PROBE = 0,
> > + POSTCOPY_NOTIFY_INBOUND_ADVISE,
> > };
> >
> > struct PostcopyNotifyData {
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index 358c5b51e2..1f2bf12a28 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -1386,6 +1386,7 @@ static int
> > loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
> > {
> > PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE);
> > uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps;
> > + Error *local_err = NULL;
> >
> > trace_loadvm_postcopy_handle_advise();
> > if (ps != POSTCOPY_INCOMING_NONE) {
> > @@ -1451,6 +1452,11 @@ static int
> > loadvm_postcopy_handle_advise(MigrationIncomingState *mis,
> > return -1;
> > }
> >
> > + if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_ADVISE, &local_err)) {
> > + error_report_err(local_err);
> > + return -1;
> > + }
> > +
> > if (ram_postcopy_incoming_init(mis)) {
> > return -1;
> > }
> > --
> > 2.14.3
> >
> >
>
>
>
> --
> Marc-André Lureau
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v4 00/29] postcopy+vhost-user/shared ram, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 01/29] migrate: Update ram_block_discard_range for shared, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 02/29] qemu_ram_block_host_offset, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 03/29] postcopy: use UFFDIO_ZEROPAGE only when available, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 06/29] vhost-user: Add 'VHOST_USER_POSTCOPY_ADVISE' message, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 05/29] postcopy: Add vhost-user flag for postcopy and check it, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 04/29] postcopy: Add notifier chain, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 07/29] libvhost-user: Support sending fds back to qemu, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 08/29] libvhost-user: Open userfaultfd, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 09/29] postcopy: Allow registering of fd handler, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 10/29] vhost+postcopy: Register shared ufd with postcopy, Dr. David Alan Gilbert (git), 2018/03/08