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X-Received-From: 2a00:1450:4864:20::444 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: QEMU , Stefan Hajnoczi , vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi On Thu, Dec 12, 2019 at 10:05 PM Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" > > If a new setmemtable command comes in once the vhost threads are > running, it will remap the guests address space and the threads > will now be looking in the wrong place. > > Fortunately we're running this command under lock, so we can > update the queue mappings so that threads will look in the new-right > place. > > Note: This doesn't fix things that the threads might be doing > without a lock (e.g. a readv/writev!) That's for another time. > > Signed-off-by: Dr. David Alan Gilbert > --- > contrib/libvhost-user/libvhost-user.c | 33 ++++++++++++++++++++------- > contrib/libvhost-user/libvhost-user.h | 3 +++ > 2 files changed, 28 insertions(+), 8 deletions(-) > > diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-use= r/libvhost-user.c > index 63e41062a4..b89bf18501 100644 > --- a/contrib/libvhost-user/libvhost-user.c > +++ b/contrib/libvhost-user/libvhost-user.c > @@ -564,6 +564,21 @@ vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg) > return false; > } > > +static bool > +map_ring(VuDev *dev, VuVirtq *vq) > +{ > + vq->vring.desc =3D qva_to_va(dev, vq->vra.desc_user_addr); > + vq->vring.used =3D qva_to_va(dev, vq->vra.used_user_addr); > + vq->vring.avail =3D qva_to_va(dev, vq->vra.avail_user_addr); > + > + DPRINT("Setting virtq addresses:\n"); > + DPRINT(" vring_desc at %p\n", vq->vring.desc); > + DPRINT(" vring_used at %p\n", vq->vring.used); > + DPRINT(" vring_avail at %p\n", vq->vring.avail); > + > + return !(vq->vring.desc && vq->vring.used && vq->vring.avail); > +} > + > static bool > vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg) > { > @@ -767,6 +782,14 @@ vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg= ) > close(vmsg->fds[i]); > } > > + for (i =3D 0; i < dev->max_queues; i++) { > + if (dev->vq[i].vring.desc) { The code usually checks for all (vq->vring.desc && vq->vring.used && vq->vring.avail). Perhaps we should introduce a VQ_RING_IS_SET() macro? > + if (map_ring(dev, &dev->vq[i])) { > + vu_panic(dev, "remaping queue %d during setmemtable", i)= ; > + } > + } > + } > + > return false; > } > > @@ -853,18 +876,12 @@ vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vm= sg) > DPRINT(" avail_user_addr: 0x%016" PRIx64 "\n", vra->avail_user_a= ddr); > DPRINT(" log_guest_addr: 0x%016" PRIx64 "\n", vra->log_guest_ad= dr); > > + vq->vra =3D *vra; > vq->vring.flags =3D vra->flags; > - vq->vring.desc =3D qva_to_va(dev, vra->desc_user_addr); > - vq->vring.used =3D qva_to_va(dev, vra->used_user_addr); > - vq->vring.avail =3D qva_to_va(dev, vra->avail_user_addr); > vq->vring.log_guest_addr =3D vra->log_guest_addr; > > - DPRINT("Setting virtq addresses:\n"); > - DPRINT(" vring_desc at %p\n", vq->vring.desc); > - DPRINT(" vring_used at %p\n", vq->vring.used); > - DPRINT(" vring_avail at %p\n", vq->vring.avail); > > - if (!(vq->vring.desc && vq->vring.used && vq->vring.avail)) { > + if (map_ring(dev, vq)) { > vu_panic(dev, "Invalid vring_addr message"); > return false; > } > diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-use= r/libvhost-user.h > index 1844b6f8d4..5cb7708559 100644 > --- a/contrib/libvhost-user/libvhost-user.h > +++ b/contrib/libvhost-user/libvhost-user.h > @@ -327,6 +327,9 @@ typedef struct VuVirtq { > int err_fd; > unsigned int enable; > bool started; > + > + /* Guest addresses of our ring */ > + struct vhost_vring_addr vra; > } VuVirtq; > > enum VuWatchCondtion { > -- > 2.23.0 > > Looks reasonable otherwise (assuming all running threads were flushed somehow by other means) --=20 Marc-Andr=C3=A9 Lureau