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path: root/hw/virtio/vhost-shadow-virtqueue.h (follow)
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* vhost: Add svq avail_handler callbackEugenio Pérez2022-07-201-1/+30
| | | | | | | | | | | | | | | This allows external handlers to be aware of new buffers that the guest places in the virtqueue. When this callback is defined the ownership of the guest's virtqueue element is transferred to the callback. This means that if the user wants to forward the descriptor it needs to manually inject it. The callback is also free to process the command by itself and use the element with svq_push. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: add vhost_svq_pollEugenio Pérez2022-07-201-0/+1
| | | | | | | | | It allows the Shadow Control VirtQueue to wait for the device to use the available buffers. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Expose vhost_svq_addEugenio Pérez2022-07-201-0/+3
| | | | | | | | | This allows external parts of SVQ to forward custom buffers to the device. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: add vhost_svq_push_elemEugenio Pérez2022-07-201-0/+3
| | | | | | | | | This function allows external SVQ users to return guest's available buffers. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Track number of descs in SVQDescStateEugenio Pérez2022-07-201-0/+6
| | | | | | | | | A guest's buffer continuos on GPA may need multiple descriptors on qemu's VA, so SVQ should track its length sepparatedly. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Add SVQDescStateEugenio Pérez2022-07-201-2/+6
| | | | | | | | | | This will allow SVQ to add context to the different queue elements. This patch only store the actual element, no functional change intended. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Track descriptor chain in private at SVQEugenio Pérez2022-05-131-0/+6
| | | | | | | | | | | | The device could have access to modify them, and it definitely have access when we implement packed vq. Harden SVQ maintaining a private copy of the descriptor chain. Other fields like buffer addresses are already maintained sepparatedly. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Message-Id: <20220512175747.142058-2-eperezma@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* vdpa: Add custom IOTLB translations to SVQEugenio Pérez2022-03-151-1/+5
| | | | | | | | | | | | | Use translations added in VhostIOVATree in SVQ. Only introduce usage here, not allocation and deallocation. As with previous patches, we use the dead code paths of shadow_vqs_enabled to avoid commiting too many changes at once. These are impossible to take at the moment. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Shadow virtqueue buffers forwardingEugenio Pérez2022-03-151-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Initial version of shadow virtqueue that actually forward buffers. There is no iommu support at the moment, and that will be addressed in future patches of this series. Since all vhost-vdpa devices use forced IOMMU, this means that SVQ is not usable at this point of the series on any device. For simplicity it only supports modern devices, that expects vring in little endian, with split ring and no event idx or indirect descriptors. Support for them will not be added in this series. It reuses the VirtQueue code for the device part. The driver part is based on Linux's virtio_ring driver, but with stripped functionality and optimizations so it's easier to review. However, forwarding buffers have some particular pieces: One of the most unexpected ones is that a guest's buffer can expand through more than one descriptor in SVQ. While this is handled gracefully by qemu's emulated virtio devices, it may cause unexpected SVQ queue full. This patch also solves it by checking for this condition at both guest's kicks and device's calls. The code may be more elegant in the future if SVQ code runs in its own iocontext. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* virtio: Add vhost_svq_get_vring_addrEugenio Pérez2022-03-151-0/+9
| | | | | | | | | | | | It reports the shadow virtqueue address from qemu virtual address space. Since this will be different from the guest's vaddr, but the device can access it, SVQ takes special care about its alignment & lack of garbage data. It assumes that IOMMU will work in host_page_size ranges for that. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Add vhost_svq_valid_features to shadow vqEugenio Pérez2022-03-151-0/+2
| | | | | | | | | | | | | | | | This allows SVQ to negotiate features with the guest and the device. For the device, SVQ is a driver. While this function bypasses all non-transport features, it needs to disable the features that SVQ does not support when forwarding buffers. This includes packed vq layout, indirect descriptors or event idx. Future changes can add support to offer more features to the guest, since the use of VirtQueue gives this for free. This is left out at the moment for simplicity. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Add Shadow VirtQueue call forwarding capabilitiesEugenio Pérez2022-03-151-0/+4
| | | | | | | | | This will make qemu aware of the device used buffers, allowing it to write the guest memory with its contents if needed. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Add Shadow VirtQueue kick forwarding capabilitiesEugenio Pérez2022-03-151-0/+14
| | | | | | | | | | | | At this mode no buffer forwarding will be performed in SVQ mode: Qemu will just forward the guest's kicks to the device. Host memory notifiers regions are left out for simplicity, and they will not be addressed in this series. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
* vhost: Add VhostShadowVirtqueueEugenio Pérez2022-03-151-0/+28
Vhost shadow virtqueue (SVQ) is an intermediate jump for virtqueue notifications and buffers, allowing qemu to track them. While qemu is forwarding the buffers and virtqueue changes, it is able to commit the memory it's being dirtied, the same way regular qemu's VirtIO devices do. This commit only exposes basic SVQ allocation and free. Next patches of the series add functionality like notifications and buffers forwarding. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>