bda324fd03
This patch introduces the control virtqueue support for vDPA simulator. This is a requirement for supporting advanced features like multiqueue. A requirement for control virtqueue is to isolate its memory access from the rx/tx virtqueues. This is because when using vDPA device for VM, the control virqueue is not directly assigned to VM. Userspace (Qemu) will present a shadow control virtqueue to control for recording the device states. The isolation is done via the virtqueue groups and ASID support in vDPA through vhost-vdpa. The simulator is extended to have: 1) three virtqueues: RXVQ, TXVQ and CVQ (control virtqueue) 2) two virtqueue groups: group 0 contains RXVQ and TXVQ; group 1 contains CVQ 3) two address spaces and the simulator simply implements the address spaces by mapping it 1:1 to IOTLB. For the VM use cases, userspace(Qemu) may set AS 0 to group 0 and AS 1 to group 1. So we have: 1) The IOTLB for virtqueue group 0 contains the mappings of guest, so RX and TX can be assigned to guest directly. 2) The IOTLB for virtqueue group 1 contains the mappings of CVQ which is the buffers that allocated and managed by VMM only. So CVQ of vhost-vdpa is visible to VMM only. And Guest can not access the CVQ of vhost-vdpa. For the other use cases, since AS 0 is associated to all virtqueue groups by default. All virtqueues share the same mapping by default. To demonstrate the function, VIRITO_NET_F_CTRL_MACADDR is implemented in the simulator for the driver to set mac address. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Gautam Dawar <gdawar@xilinx.com> Message-Id: <20220330180436.24644-20-gdawar@xilinx.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Linux kernel
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