dff4426fa6
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>
118 lines
3.1 KiB
C
118 lines
3.1 KiB
C
/*
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* vhost shadow virtqueue
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*
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* SPDX-FileCopyrightText: Red Hat, Inc. 2021
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* SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "qemu/osdep.h"
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#include "hw/virtio/vhost-shadow-virtqueue.h"
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#include "qemu/error-report.h"
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#include "qemu/main-loop.h"
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#include "linux-headers/linux/vhost.h"
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/**
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* Forward guest notifications.
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*
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* @n: guest kick event notifier, the one that guest set to notify svq.
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*/
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static void vhost_handle_guest_kick(EventNotifier *n)
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{
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VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue, svq_kick);
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event_notifier_test_and_clear(n);
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event_notifier_set(&svq->hdev_kick);
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}
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/**
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* Set a new file descriptor for the guest to kick the SVQ and notify for avail
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*
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* @svq: The svq
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* @svq_kick_fd: The svq kick fd
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*
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* Note that the SVQ will never close the old file descriptor.
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*/
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void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd)
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{
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EventNotifier *svq_kick = &svq->svq_kick;
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bool poll_stop = VHOST_FILE_UNBIND != event_notifier_get_fd(svq_kick);
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bool poll_start = svq_kick_fd != VHOST_FILE_UNBIND;
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if (poll_stop) {
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event_notifier_set_handler(svq_kick, NULL);
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}
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/*
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* event_notifier_set_handler already checks for guest's notifications if
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* they arrive at the new file descriptor in the switch, so there is no
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* need to explicitly check for them.
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*/
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if (poll_start) {
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event_notifier_init_fd(svq_kick, svq_kick_fd);
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event_notifier_set(svq_kick);
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event_notifier_set_handler(svq_kick, vhost_handle_guest_kick);
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}
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}
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/**
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* Stop the shadow virtqueue operation.
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* @svq: Shadow Virtqueue
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*/
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void vhost_svq_stop(VhostShadowVirtqueue *svq)
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{
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event_notifier_set_handler(&svq->svq_kick, NULL);
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}
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/**
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* Creates vhost shadow virtqueue, and instructs the vhost device to use the
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* shadow methods and file descriptors.
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*
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* Returns the new virtqueue or NULL.
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*
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* In case of error, reason is reported through error_report.
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*/
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VhostShadowVirtqueue *vhost_svq_new(void)
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{
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g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
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int r;
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r = event_notifier_init(&svq->hdev_kick, 0);
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if (r != 0) {
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error_report("Couldn't create kick event notifier: %s (%d)",
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g_strerror(errno), errno);
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goto err_init_hdev_kick;
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}
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r = event_notifier_init(&svq->hdev_call, 0);
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if (r != 0) {
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error_report("Couldn't create call event notifier: %s (%d)",
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g_strerror(errno), errno);
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goto err_init_hdev_call;
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}
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event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
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return g_steal_pointer(&svq);
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err_init_hdev_call:
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event_notifier_cleanup(&svq->hdev_kick);
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err_init_hdev_kick:
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return NULL;
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}
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/**
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* Free the resources of the shadow virtqueue.
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*
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* @pvq: gpointer to SVQ so it can be used by autofree functions.
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*/
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void vhost_svq_free(gpointer pvq)
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{
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VhostShadowVirtqueue *vq = pvq;
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vhost_svq_stop(vq);
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event_notifier_cleanup(&vq->hdev_kick);
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event_notifier_cleanup(&vq->hdev_call);
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g_free(vq);
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}
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