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Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
virtio, pc: fixes, cleanups A bunch of fixes all over the place. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Thu 25 Jul 2019 16:19:33 BST # gpg: using RSA key 281F0DB8D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [full] # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" [full] # Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67 # Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA 8A0D 281F 0DB8 D28D 5469 * remotes/mst/tags/for_upstream: virtio-balloon: free pbp more aggressively virtio-balloon: don't track subpages for the PBP virtio-balloon: Use temporary PBP only virtio-balloon: Rework pbp tracking data virtio-balloon: Better names for offset variables in inflate/deflate code virtio-balloon: Simplify deflate with pbp virtio-balloon: Fix QEMU crashes on pagesize > BALLOON_PAGE_SIZE virtio-balloon: Fix wrong sign extension of PFNs i386/acpi: show PCI Express bus on pxb-pcie expanders ioapic: kvm: Skip route updates for masked pins i386/acpi: fix gint overflow in crs_range_compare docs: clarify multiqueue vs multiple virtqueues Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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@ -324,6 +324,15 @@ must support changing some configuration aspects on the fly.
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Multiple queue support
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----------------------
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Many devices have a fixed number of virtqueues. In this case the master
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already knows the number of available virtqueues without communicating with the
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slave.
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Some devices do not have a fixed number of virtqueues. Instead the maximum
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number of virtqueues is chosen by the slave. The number can depend on host
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resource availability or slave implementation details. Such devices are called
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multiple queue devices.
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Multiple queue support allows the slave to advertise the maximum number of
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queues. This is treated as a protocol extension, hence the slave has to
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implement protocol features first. The multiple queues feature is supported
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@ -339,6 +348,14 @@ queue in the sent message to identify a specified queue.
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The master enables queues by sending message ``VHOST_USER_SET_VRING_ENABLE``.
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vhost-user-net has historically automatically enabled the first queue pair.
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Slaves should always implement the ``VHOST_USER_PROTOCOL_F_MQ`` protocol
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feature, even for devices with a fixed number of virtqueues, since it is simple
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to implement and offers a degree of introspection.
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Masters must not rely on the ``VHOST_USER_PROTOCOL_F_MQ`` protocol feature for
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devices with a fixed number of virtqueues. Only true multiqueue devices
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require this protocol feature.
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Migration
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---------
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