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Re: [Qemu-devel] [PATCH v3 13/28] vhost-user: check vhost_user_{read, wr
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH v3 13/28] vhost-user: check vhost_user_{read, write}() return value |
Date: |
Thu, 21 Jul 2016 03:55:05 -0400 (EDT) |
Hi
----- Original Message -----
> On Wed, Jul 06, 2016 at 08:47:06PM +0200, address@hidden wrote:
> > From: Marc-André Lureau <address@hidden>
> >
> > More error checking to break code flow and report appropriate errors.
> >
> > Signed-off-by: Marc-André Lureau <address@hidden>
>
> So this will cause asserts here:
>
> /* inform backend of log switching, this must be done before
> releasing the current log, to ensure no logging is lost */
> r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log);
> assert(r >= 0);
That's why there is a previous patch "vhost: do not assert() on vhost_ops
failure". Although there is still some abort() on migration. This is a corner
case that isn't yet solved. I think it would make sense for the backend to
state that it is disconnected, and for vhost to ingore migration ops failure in
this case.
> which is the opposite of what we want.
>
> For vhost_net ioctl failure is a fatal error bit for
> vhost user this means backend exited and will not change
> memory so it's benign.
>
> the right thing to do is to return 0 status to caller on most errors.
>
> If that is necessary for debugging, add a printout for now.
Yes, I am adding a VHOST_OPS_DEBUG as you proposed
>
> > ---
> > hw/virtio/vhost-user.c | 50
> > ++++++++++++++++++++++++++++++++++----------------
> > 1 file changed, 34 insertions(+), 16 deletions(-)
> >
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 5dae496..819481d 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -214,12 +214,14 @@ static int vhost_user_set_log_base(struct vhost_dev
> > *dev, uint64_t base,
> > fds[fd_num++] = log->fd;
> > }
> >
> > - vhost_user_write(dev, &msg, fds, fd_num);
> > + if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
> > + return -1;
> > + }
> >
> > if (shmfd) {
> > msg.size = 0;
> > if (vhost_user_read(dev, &msg) < 0) {
> > - return 0;
> > + return -1;
> > }
> >
> > if (msg.request != VHOST_USER_SET_LOG_BASE) {
> > @@ -275,7 +277,9 @@ static int vhost_user_set_mem_table(struct vhost_dev
> > *dev,
> > msg.size += sizeof(msg.payload.memory.padding);
> > msg.size += fd_num * sizeof(VhostUserMemoryRegion);
> >
> > - vhost_user_write(dev, &msg, fds, fd_num);
> > + if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -290,7 +294,9 @@ static int vhost_user_set_vring_addr(struct vhost_dev
> > *dev,
> > .size = sizeof(msg.payload.addr),
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -313,7 +319,9 @@ static int vhost_set_vring(struct vhost_dev *dev,
> > .size = sizeof(msg.payload.state),
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -360,10 +368,12 @@ static int vhost_user_get_vring_base(struct vhost_dev
> > *dev,
> > .size = sizeof(msg.payload.state),
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > if (vhost_user_read(dev, &msg) < 0) {
> > - return 0;
> > + return -1;
> > }
> >
> > if (msg.request != VHOST_USER_GET_VRING_BASE) {
> > @@ -401,7 +411,9 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
> > msg.payload.u64 |= VHOST_USER_VRING_NOFD_MASK;
> > }
> >
> > - vhost_user_write(dev, &msg, fds, fd_num);
> > + if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -427,7 +439,9 @@ static int vhost_user_set_u64(struct vhost_dev *dev,
> > int request, uint64_t u64)
> > .size = sizeof(msg.payload.u64),
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -455,10 +469,12 @@ static int vhost_user_get_u64(struct vhost_dev *dev,
> > int request, uint64_t *u64)
> > return 0;
> > }
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > if (vhost_user_read(dev, &msg) < 0) {
> > - return 0;
> > + return -1;
> > }
> >
> > if (msg.request != request) {
> > @@ -489,7 +505,9 @@ static int vhost_user_set_owner(struct vhost_dev *dev)
> > .flags = VHOST_USER_VERSION,
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -501,7 +519,9 @@ static int vhost_user_reset_device(struct vhost_dev
> > *dev)
> > .flags = VHOST_USER_VERSION,
> > };
> >
> > - vhost_user_write(dev, &msg, NULL, 0);
> > + if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> > + return -1;
> > + }
> >
> > return 0;
> > }
> > @@ -588,7 +608,6 @@ static bool vhost_user_requires_shm_log(struct
> > vhost_dev *dev)
> > static int vhost_user_migration_done(struct vhost_dev *dev, char*
> > mac_addr)
> > {
> > VhostUserMsg msg = { 0 };
> > - int err;
> >
> > assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
> >
> > @@ -605,8 +624,7 @@ static int vhost_user_migration_done(struct vhost_dev
> > *dev, char* mac_addr)
> > memcpy((char *)&msg.payload.u64, mac_addr, 6);
> > msg.size = sizeof(msg.payload.u64);
> >
> > - err = vhost_user_write(dev, &msg, NULL, 0);
> > - return err;
> > + return vhost_user_write(dev, &msg, NULL, 0);
> > }
> > return -1;
> > }
> > --
> > 2.9.0
>
- [Qemu-devel] [PATCH v3 10/28] vhost: change some assert() for error_report() or silent fail, (continued)
[Qemu-devel] [PATCH v3 11/28] vhost: use error_report() instead of fprintf(stderr, ...), marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 12/28] vhost-user: check qemu_chr_fe_set_msgfds() return value, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 13/28] vhost-user: check vhost_user_{read, write}() return value, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 14/28] qemu-char: check socket is actually connected, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 15/28] vhost-user: keep vhost_net after a disconnection, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 16/28] Revert "vhost-net: do not crash if backend is not present", marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 17/28] get_vhost_net() should be != null after vhost_user_init, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 18/28] vhost-net: success if backend has no ops->vhost_migration_done, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 19/28] vhost: add assert() to check runtime behaviour, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 20/28] char: add chr_wait_connected callback, marcandre . lureau, 2016/07/06
[Qemu-devel] [PATCH v3 21/28] char: add and use tcp_chr_wait_connected, marcandre . lureau, 2016/07/06