On Tue, Jan 28, 2025 at 07:50:01AM +0100, Stefano Brivio wrote: > On Tue, 28 Jan 2025 12:40:12 +1100 > David Gibson wrote: > > > On Tue, Jan 28, 2025 at 12:15:31AM +0100, Stefano Brivio wrote: > > > Add two sets (source or target) of three functions each for passt in > > > vhost-user mode, triggered by activity on the file descriptor passed > > > via VHOST_USER_PROTOCOL_F_DEVICE_STATE: > > > > > > - migrate_source_pre() and migrate_target_pre() are called to prepare > > > for migration, before data is transferred > > > > > > - migrate_source() sends, and migrate_target() receives migration data > > > > > > - migrate_source_post() and migrate_target_post() are responsible for > > > any post-migration task > > > > > > Callbacks are added to these functions with arrays of function > > > pointers in migrate.c. Migration handlers are versioned. > > > > > > Versioned descriptions of data sections will be added to the > > > data_versions array, which points to versioned iovec arrays. Version > > > 1 is currently empty and will be filled in in subsequent patches. > > > > > > The source announces the data version to be used and informs the peer > > > about endianness, and the size of void *, time_t, flow entries and > > > flow hash table entries. > > > > > > The target checks if the version of the source is still supported. If > > > it's not, it aborts the migration. > > > > > > Signed-off-by: Stefano Brivio > > > --- > > > Makefile | 12 +-- > > > migrate.c | 259 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > migrate.h | 90 ++++++++++++++++++ > > > passt.c | 2 +- > > > vu_common.c | 122 ++++++++++++++++--------- > > > vu_common.h | 2 +- > > > 6 files changed, 438 insertions(+), 49 deletions(-) > > > create mode 100644 migrate.c > > > create mode 100644 migrate.h > > > > > > diff --git a/Makefile b/Makefile > > > index 464eef1..1383875 100644 > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -38,8 +38,8 @@ FLAGS += -DDUAL_STACK_SOCKETS=$(DUAL_STACK_SOCKETS) > > > > > > PASST_SRCS = arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c fwd.c \ > > > icmp.c igmp.c inany.c iov.c ip.c isolation.c lineread.c log.c mld.c \ > > > - ndp.c netlink.c packet.c passt.c pasta.c pcap.c pif.c tap.c tcp.c \ > > > - tcp_buf.c tcp_splice.c tcp_vu.c udp.c udp_flow.c udp_vu.c util.c \ > > > + ndp.c netlink.c migrate.c packet.c passt.c pasta.c pcap.c pif.c tap.c \ > > > + tcp.c tcp_buf.c tcp_splice.c tcp_vu.c udp.c udp_flow.c udp_vu.c util.c \ > > > vhost_user.c virtio.c vu_common.c > > > QRAP_SRCS = qrap.c > > > SRCS = $(PASST_SRCS) $(QRAP_SRCS) > > > @@ -48,10 +48,10 @@ MANPAGES = passt.1 pasta.1 qrap.1 > > > > > > PASST_HEADERS = arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h fwd.h \ > > > flow_table.h icmp.h icmp_flow.h inany.h iov.h ip.h isolation.h \ > > > - lineread.h log.h ndp.h netlink.h packet.h passt.h pasta.h pcap.h pif.h \ > > > - siphash.h tap.h tcp.h tcp_buf.h tcp_conn.h tcp_internal.h tcp_splice.h \ > > > - tcp_vu.h udp.h udp_flow.h udp_internal.h udp_vu.h util.h vhost_user.h \ > > > - virtio.h vu_common.h > > > + lineread.h log.h migrate.h ndp.h netlink.h packet.h passt.h pasta.h \ > > > + pcap.h pif.h siphash.h tap.h tcp.h tcp_buf.h tcp_conn.h tcp_internal.h \ > > > + tcp_splice.h tcp_vu.h udp.h udp_flow.h udp_internal.h udp_vu.h util.h \ > > > + vhost_user.h virtio.h vu_common.h > > > HEADERS = $(PASST_HEADERS) seccomp.h > > > > > > C := \#include \nint main(){int a=getrandom(0, 0, 0);} > > > diff --git a/migrate.c b/migrate.c > > > new file mode 100644 > > > index 0000000..bee9653 > > > --- /dev/null > > > +++ b/migrate.c > > > @@ -0,0 +1,259 @@ > > > +// SPDX-License-Identifier: GPL-2.0-or-later > > > + > > > +/* PASST - Plug A Simple Socket Transport > > > + * for qemu/UNIX domain socket mode > > > + * > > > + * PASTA - Pack A Subtle Tap Abstraction > > > + * for network namespace/tap device mode > > > + * > > > + * migrate.c - Migration sections, layout, and routines > > > + * > > > + * Copyright (c) 2025 Red Hat GmbH > > > + * Author: Stefano Brivio > > > + */ > > > + > > > +#include > > > +#include > > > + > > > +#include "util.h" > > > +#include "ip.h" > > > +#include "passt.h" > > > +#include "inany.h" > > > +#include "flow.h" > > > +#include "flow_table.h" > > > + > > > +#include "migrate.h" > > > + > > > +/* Current version of migration data */ > > > +#define MIGRATE_VERSION 1 > > > + > > > +/* Magic as we see it and as seen with reverse endianness */ > > > +#define MIGRATE_MAGIC 0xB1BB1D1B0BB1D1B0 > > > +#define MIGRATE_MAGIC_SWAPPED 0xB0D1B10B1B1DBBB1 > > > > As noted, I'm hoping we can get rid of "either endian" migration. But > > if this stays, we should define it using __bswap_constant_32() to > > avoid embarrassing mistakes. > > Those always give me issues on musl, What sort of issues? We're already using them, and have fallback versions defined in util.h > so I'd rather test things on > big-endian and realise it's actually 0xB0D1B1B01B1DBBB1 (0x0b bitswap). > > Feel free to post a different proposal if tested. > > > > + > > > +/* Migration header to send from source */ > > > +static union migrate_header header = { > > > + .magic = MIGRATE_MAGIC, > > > + .version = htonl_constant(MIGRATE_VERSION), > > > + .time_t_size = htonl_constant(sizeof(time_t)), > > > + .flow_size = htonl_constant(sizeof(union flow)), > > > + .flow_sidx_size = htonl_constant(sizeof(struct flow_sidx)), > > > + .voidp_size = htonl_constant(sizeof(void *)), > > > +}; > > > + > > > +/* Data sections for version 1 */ > > > +static struct iovec sections_v1[] = { > > > + { &header, sizeof(header) }, > > > +}; > > > + > > > +/* Set of data versions */ > > > +static struct migrate_data data_versions[] = { > > > + { > > > + 1, sections_v1, > > > + }, > > > + { 0 }, > > > +}; > > > + > > > +/* Handlers to call in source before sending data */ > > > +struct migrate_handler handlers_source_pre[] = { > > > + { 0 }, > > > +}; > > > + > > > +/* Handlers to call in source after sending data */ > > > +struct migrate_handler handlers_source_post[] = { > > > + { 0 }, > > > +}; > > > + > > > +/* Handlers to call in target before receiving data with version 1 */ > > > +struct migrate_handler handlers_target_pre_v1[] = { > > > + { 0 }, > > > +}; > > > + > > > +/* Handlers to call in target after receiving data with version 1 */ > > > +struct migrate_handler handlers_target_post_v1[] = { > > > + { 0 }, > > > +}; > > > + > > > +/* Versioned sets of migration handlers */ > > > +struct migrate_target_handlers target_handlers[] = { > > > + { > > > + 1, > > > + handlers_target_pre_v1, > > > + handlers_target_post_v1, > > > + }, > > > + { 0 }, > > > +}; > > > + > > > +/** > > > + * migrate_source_pre() - Pre-migration tasks as source > > > + * @m: Migration metadata > > > + * > > > + * Return: 0 on success, error code on failure > > > + */ > > > +int migrate_source_pre(struct migrate_meta *m) > > > +{ > > > + struct migrate_handler *h; > > > + > > > + for (h = handlers_source_pre; h->fn; h++) { > > > + int rc; > > > + > > > + if ((rc = h->fn(m, h->data))) > > > + return rc; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * migrate_source() - Perform migration as source: send state to hypervisor > > > + * @fd: Descriptor for state transfer > > > + * @m: Migration metadata > > > + * > > > + * Return: 0 on success, error code on failure > > > + */ > > > +int migrate_source(int fd, const struct migrate_meta *m) > > > +{ > > > + static struct migrate_data *d; > > > + unsigned count; > > > + int rc; > > > + > > > + for (d = data_versions; d->v != MIGRATE_VERSION; d++); > > > > Should ASSERT() if we don't find the version within the array. > > This looks a bit unnecessary, MIGRATE_VERSION is defined just above... > it's just a readability killer to me. > > > > + for (count = 0; d->sections[count].iov_len; count++); > > > + > > > + debug("Writing %u migration sections", count - 1 /* minus header */); > > > + rc = write_remainder(fd, d->sections, count, 0); > > > + if (rc < 0) > > > + return errno; > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * migrate_source_post() - Post-migration tasks as source > > > + * @m: Migration metadata > > > + * > > > + * Return: 0 on success, error code on failure > > > + */ > > > +void migrate_source_post(struct migrate_meta *m) > > > +{ > > > + struct migrate_handler *h; > > > + > > > + for (h = handlers_source_post; h->fn; h++) > > > + h->fn(m, h->data); > > > > Is there actually anything we might need to do on the source after a > > successful migration, other than exit? > > We might want to log a couple of things, which would warrant these > handlers. > > But let's say we need to do something *similar* to "updating the > network" such as the RARP announcement that QEMU is requesting (this is IIUC, that's on the target end, not the source end... > intended for OVN-Kubernetes, so go figure), or that we need a > workaround for a kernel issue with implicit close() with TCP_REPAIR > on... I would leave this in for completeness. ...but sure, point taken. > > > +} > > > + > > > +/** > > > + * migrate_target_read_header() - Set metadata in target from source header > > > + * @fd: Descriptor for state transfer > > > + * @m: Migration metadata, filled on return > > > + * > > > + * Return: 0 on success, error code on failure > > > > We nearly always use negative error codes. Why not here? > > Because the reply to VHOST_USER_SET_DEVICE_STATE_FD is unsigned: > > https://qemu-project.gitlab.io/qemu/interop/vhost-user.html#front-end-message-types > > and I want to keep this consistent/untranslated. Ok. > > > + */ > > > +int migrate_target_read_header(int fd, struct migrate_meta *m) > > > +{ > > > + static struct migrate_data *d; > > > + union migrate_header h; > > > + > > > + if (read_all_buf(fd, &h, sizeof(h))) > > > + return errno; > > > + > > > + debug("Source magic: 0x%016" PRIx64 ", sizeof(void *): %u, version: %u", > > > + h.magic, ntohl(h.voidp_size), ntohl(h.version)); > > > + > > > + for (d = data_versions; d->v != ntohl(h.version); d++); > > > + if (!d->v) > > > + return ENOTSUP; > > > > This is too late. The loop doesn't check it, so you've already > > overrun the data_versions table if the version wasn't in there. > > Ah, yes, I forgot the '&& d->v' part (see migrate_target()). > > > Easier to use an ARRAY_SIZE() limit in the loop, I think. > > I'd rather keep that as a one-liner, and NULL-terminate the arrays. > > > > + m->v = d->v; > > > + > > > + if (h.magic == MIGRATE_MAGIC) > > > + m->bswap = false; > > > + else if (h.magic == MIGRATE_MAGIC_SWAPPED) > > > + m->bswap = true; > > > + else > > > + return ENOTSUP; > > > + > > > + if (ntohl(h.voidp_size) == 4) > > > + m->source_64b = false; > > > + else if (ntohl(h.voidp_size) == 8) > > > + m->source_64b = true; > > > + else > > > + return ENOTSUP; > > > + > > > + if (ntohl(h.time_t_size) == 4) > > > + m->time_64b = false; > > > + else if (ntohl(h.time_t_size) == 8) > > > + m->time_64b = true; > > > + else > > > + return ENOTSUP; > > > + > > > + m->flow_size = ntohl(h.flow_size); > > > + m->flow_sidx_size = ntohl(h.flow_sidx_size); > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * migrate_target_pre() - Pre-migration tasks as target > > > + * @m: Migration metadata > > > + * > > > + * Return: 0 on success, error code on failure > > > + */ > > > +int migrate_target_pre(struct migrate_meta *m) > > > +{ > > > + struct migrate_target_handlers *th; > > > + struct migrate_handler *h; > > > + > > > + for (th = target_handlers; th->v != m->v && th->v; th++); > > > + > > > + for (h = th->pre; h->fn; h++) { > > > + int rc; > > > + > > > + if ((rc = h->fn(m, h->data))) > > > + return rc; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * migrate_target() - Perform migration as target: receive state from hypervisor > > > + * @fd: Descriptor for state transfer > > > + * @m: Migration metadata > > > + * > > > + * Return: 0 on success, error code on failure > > > + * > > > + * #syscalls:vu readv > > > + */ > > > +int migrate_target(int fd, const struct migrate_meta *m) > > > +{ > > > + static struct migrate_data *d; > > > + unsigned cnt; > > > + int rc; > > > + > > > + for (d = data_versions; d->v != m->v && d->v; d++); > > > + > > > + for (cnt = 0; d->sections[cnt + 1 /* skip header */].iov_len; cnt++); > > > + > > > + debug("Reading %u migration sections", cnt); > > > + rc = read_remainder(fd, d->sections + 1, cnt, 0); > > > + if (rc < 0) > > > + return errno; > > > + > > > + return 0; > > > +} > > > + > > > +/** > > > + * migrate_target_post() - Post-migration tasks as target > > > + * @m: Migration metadata > > > + */ > > > +void migrate_target_post(struct migrate_meta *m) > > > +{ > > > + struct migrate_target_handlers *th; > > > + struct migrate_handler *h; > > > + > > > + for (th = target_handlers; th->v != m->v && th->v; th++); > > > + > > > + for (h = th->post; h->fn; h++) > > > + h->fn(m, h->data); > > > +} > > > diff --git a/migrate.h b/migrate.h > > > new file mode 100644 > > > index 0000000..5582f75 > > > --- /dev/null > > > +++ b/migrate.h > > > @@ -0,0 +1,90 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-or-later > > > + * Copyright (c) 2025 Red Hat GmbH > > > + * Author: Stefano Brivio > > > + */ > > > + > > > +#ifndef MIGRATE_H > > > +#define MIGRATE_H > > > + > > > +/** > > > + * struct migrate_meta - Migration metadata > > > + * @v: Chosen migration data version, host order > > > + * @bswap: Source has opposite endianness > > > + * @peer_64b: Source uses 64-bit void * > > > + * @time_64b: Source uses 64-bit time_t > > > + * @flow_size: Size of union flow in source > > > + * @flow_sidx_size: Size of struct flow_sidx in source > > > + */ > > > +struct migrate_meta { > > > + uint32_t v; > > > + bool bswap; > > > + bool source_64b; > > > + bool time_64b; > > > + size_t flow_size; > > > + size_t flow_sidx_size; > > > +}; > > > + > > > +/** > > > + * union migrate_header - Migration header from source > > > + * @magic: 0xB1BB1D1B0BB1D1B0, host order > > > + * @version: Source sends highest known, target aborts if unsupported > > > + * @voidp_size: sizeof(void *), network order > > > + * @time_t_size: sizeof(time_t), network order > > > + * @flow_size: sizeof(union flow), network order > > > + * @flow_sidx_size: sizeof(struct flow_sidx_t), network order > > > + * @unused: Go figure > > > + */ > > > +union migrate_header { > > > + struct { > > > + uint64_t magic; > > > + uint32_t version; > > > + uint32_t voidp_size; > > > + uint32_t time_t_size; > > > + uint32_t flow_size; > > > + uint32_t flow_sidx_size; > > > + }; > > > + uint8_t unused[65536]; > > > > So, having looked at this, I no longer think padding the header to 64kiB > > is a good idea. The structure means we're basically stuck always > > having that chunky header. Instead, I think the header should be > > absolutely minimal: basically magic and version only. v1 (and maybe > > others) can add a "metadata" or whatever section for additional > > information like this they need. > > The header is processed by the target in a separate, preliminary step, > though. > > That's why I added metadata right in the header: if the target needs to > abort the migration because, say, the size of a flow entry is too big > to handle for a particular version, then we should know that before > migrate_target_pre(). Ah, yes, I missed that, we'd need a more complex design to do additional transfers and checks before making the target_pre callbacks. > As long as we check the version first, we can always shrink the header > later on. *thinks*.. I guess so, though it's kind of awkward; a future version would have to read the "header of the header", check the version, then if it's the old one, read the remainder of the 64kiB block. I still think we should clearly separate the part that we're committing to being in every future version (which I think should just be magic and version), from the stuff that's just v1. > But having 64 KiB reserved looks more robust because it's a > safe place to add this kind of metadata. > > Note that 64 KiB is typically transferred in a single read/write > from/to the vhost-user back-end. Ok, but it also has to go over the qemu migration channel, which will often be a physical link, not a super-fast local/virtual one, and may be bandwidth capped as well. I'm not actually certain if 64kiB is likely to be a problem there, but it *is* large compared to the state blobs of most qemu devices (usually only a few hundred bytes). > > > +}; > > > + > > > +/** > > > + * struct migrate_data - Data sections for given source version > > > + * @v: Source version this applies to, host order > > > + * @sections: Array of data sections, NULL-terminated > > > + */ > > > +struct migrate_data { > > > + uint32_t v; > > > + struct iovec *sections; > > > +}; > > > + > > > +/** > > > + * struct migrate_handler - Function to handle a specific data section > > > + * @fn: Function pointer taking pointer to data section > > > + * @data: Associated data section > > > + */ > > > +struct migrate_handler { > > > + int (*fn)(struct migrate_meta *m, void *data); > > > + void *data; > > > +}; > > > + > > > +/** > > > + * struct migrate_target_handlers - Versioned sets of migration target handlers > > > + * @v: Source version this applies to, host order > > > + * @pre: Set of functions to execute in target before data copy > > > + * @post: Set of functions to execute in target after data copy > > > + */ > > > +struct migrate_target_handlers { > > > + uint32_t v; > > > + struct migrate_handler *pre; > > > + struct migrate_handler *post; > > > +}; > > > + > > > +int migrate_source_pre(struct migrate_meta *m); > > > +int migrate_source(int fd, const struct migrate_meta *m); > > > +void migrate_source_post(struct migrate_meta *m); > > > + > > > +int migrate_target_read_header(int fd, struct migrate_meta *m); > > > +int migrate_target_pre(struct migrate_meta *m); > > > +int migrate_target(int fd, const struct migrate_meta *m); > > > +void migrate_target_post(struct migrate_meta *m); > > > + > > > +#endif /* MIGRATE_H */ > > > diff --git a/passt.c b/passt.c > > > index b1c8ab6..184d4e5 100644 > > > --- a/passt.c > > > +++ b/passt.c > > > @@ -358,7 +358,7 @@ loop: > > > vu_kick_cb(c.vdev, ref, &now); > > > break; > > > case EPOLL_TYPE_VHOST_MIGRATION: > > > - vu_migrate(c.vdev, eventmask); > > > + vu_migrate(&c, eventmask); > > > break; > > > default: > > > /* Can't happen */ > > > diff --git a/vu_common.c b/vu_common.c > > > index f43d8ac..0c67bd0 100644 > > > --- a/vu_common.c > > > +++ b/vu_common.c > > > @@ -5,6 +5,7 @@ > > > * common_vu.c - vhost-user common UDP and TCP functions > > > */ > > > > > > +#include > > > #include > > > #include > > > #include > > > @@ -17,6 +18,7 @@ > > > #include "vhost_user.h" > > > #include "pcap.h" > > > #include "vu_common.h" > > > +#include "migrate.h" > > > > > > #define VU_MAX_TX_BUFFER_NB 2 > > > > > > @@ -305,50 +307,88 @@ err: > > > } > > > > > > /** > > > - * vu_migrate() - Send/receive passt insternal state to/from QEMU > > > - * @vdev: vhost-user device > > > + * vu_migrate_source() - Migration as source, send state to hypervisor > > > + * @fd: File descriptor for state transfer > > > + * > > > + * Return: 0 on success, positive error code on failure > > > + */ > > > +static int vu_migrate_source(int fd) > > > +{ > > > + struct migrate_meta m; > > > + int rc; > > > + > > > + if ((rc = migrate_source_pre(&m))) { > > > + err("Source pre-migration failed: %s, abort", strerror_(rc)); > > > + return rc; > > > + } > > > + > > > + debug("Saving backend state"); > > > + > > > + rc = migrate_source(fd, &m); > > > + if (rc) > > > + err("Source migration failed: %s", strerror_(rc)); > > > + else > > > + migrate_source_post(&m); > > > + > > > + return rc; > > > > After a successful source migration shouldn't we exit, or at least > > quiesce ourselves so we don't accidentally mess with anything the > > target is now doing? > > Maybe, yes. Pending TCP connections should be safe because with > TCP_REPAIR they're already quiesced, but we don't close listening > sockets (yet). > > Perhaps a reasonable approach for the moment would be to declare a > single migrate_source_post handler logging a info() message and > exiting. Seems sensible for now. > > > +} > > > + > > > +/** > > > + * vu_migrate_target() - Migration as target, receive state from hypervisor > > > + * @fd: File descriptor for state transfer > > > + * > > > + * Return: 0 on success, positive error code on failure > > > + */ > > > +static int vu_migrate_target(int fd) > > > +{ > > > + struct migrate_meta m; > > > + int rc; > > > + > > > + rc = migrate_target_read_header(fd, &m); > > > + if (rc) { > > > + err("Migration header check failed: %s, abort", strerror_(rc)); > > > + return rc; > > > + } > > > + > > > + if ((rc = migrate_target_pre(&m))) { > > > + err("Target pre-migration failed: %s, abort", strerror_(rc)); > > > + return rc; > > > + } > > > + > > > + debug("Loading backend state"); > > > + > > > + rc = migrate_target(fd, &m); > > > + if (rc) > > > + err("Target migration failed: %s", strerror_(rc)); > > > + else > > > + migrate_target_post(&m); > > > + > > > + return rc; > > > +} > > > + > > > +/** > > > + * vu_migrate() - Send/receive passt internal state to/from QEMU > > > + * @c: Execution context > > > * @events: epoll events > > > */ > > > -void vu_migrate(struct vu_dev *vdev, uint32_t events) > > > +void vu_migrate(struct ctx *c, uint32_t events) > > > { > > > - int ret; > > > + struct vu_dev *vdev = c->vdev; > > > + int rc = EIO; > > > > > > - /* TODO: collect/set passt internal state > > > - * and use vdev->device_state_fd to send/receive it > > > - */ > > > debug("vu_migrate fd %d events %x", vdev->device_state_fd, events); > > > - if (events & EPOLLOUT) { > > > - debug("Saving backend state"); > > > - > > > - /* send some stuff */ > > > - ret = write(vdev->device_state_fd, "PASST", 6); > > > - /* value to be returned by VHOST_USER_CHECK_DEVICE_STATE */ > > > - vdev->device_state_result = ret == -1 ? -1 : 0; > > > - /* Closing the file descriptor signals the end of transfer */ > > > - epoll_ctl(vdev->context->epollfd, EPOLL_CTL_DEL, > > > - vdev->device_state_fd, NULL); > > > - close(vdev->device_state_fd); > > > - vdev->device_state_fd = -1; > > > - } else if (events & EPOLLIN) { > > > - char buf[6]; > > > - > > > - debug("Loading backend state"); > > > - /* read some stuff */ > > > - ret = read(vdev->device_state_fd, buf, sizeof(buf)); > > > - /* value to be returned by VHOST_USER_CHECK_DEVICE_STATE */ > > > - if (ret != sizeof(buf)) { > > > - vdev->device_state_result = -1; > > > - } else { > > > - ret = strncmp(buf, "PASST", sizeof(buf)); > > > - vdev->device_state_result = ret == 0 ? 0 : -1; > > > - } > > > - } else if (events & EPOLLHUP) { > > > - debug("Closing migration channel"); > > > - > > > - /* The end of file signals the end of the transfer. */ > > > - epoll_ctl(vdev->context->epollfd, EPOLL_CTL_DEL, > > > - vdev->device_state_fd, NULL); > > > - close(vdev->device_state_fd); > > > - vdev->device_state_fd = -1; > > > - } > > > + > > > + if (events & EPOLLOUT) > > > + rc = vu_migrate_source(vdev->device_state_fd); > > > + else if (events & EPOLLIN) > > > + rc = vu_migrate_target(vdev->device_state_fd); > > > + > > > + /* EPOLLHUP without EPOLLIN/EPOLLOUT, or EPOLLERR? Migration failed */ > > > + > > > + vdev->device_state_result = rc; > > > + > > > + epoll_ctl(c->epollfd, EPOLL_CTL_DEL, vdev->device_state_fd, NULL); > > > + debug("Closing migration channel"); > > > + close(vdev->device_state_fd); > > > + vdev->device_state_fd = -1; > > > } > > > diff --git a/vu_common.h b/vu_common.h > > > index d56c021..69c4006 100644 > > > --- a/vu_common.h > > > +++ b/vu_common.h > > > @@ -57,5 +57,5 @@ void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq, > > > void vu_kick_cb(struct vu_dev *vdev, union epoll_ref ref, > > > const struct timespec *now); > > > int vu_send_single(const struct ctx *c, const void *buf, size_t size); > > > -void vu_migrate(struct vu_dev *vdev, uint32_t events); > > > +void vu_migrate(struct ctx *c, uint32_t events); > > > #endif /* VU_COMMON_H */ > > > -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson