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-rw-r--r--app-emulation/qemu/files/qemu-7.0.0-virtio-scsi-fixes.patch182
1 files changed, 0 insertions, 182 deletions
diff --git a/app-emulation/qemu/files/qemu-7.0.0-virtio-scsi-fixes.patch b/app-emulation/qemu/files/qemu-7.0.0-virtio-scsi-fixes.patch
deleted file mode 100644
index 9ec6ede80896..000000000000
--- a/app-emulation/qemu/files/qemu-7.0.0-virtio-scsi-fixes.patch
+++ /dev/null
@@ -1,182 +0,0 @@
-https://bugs.gentoo.org/849500
-https://gitlab.com/qemu-project/qemu/-/commit/2f743ef6366c2df4ef51ef3ae318138cdc0125ab.patch
-https://gitlab.com/qemu-project/qemu/-/commit/38738f7dbbda90fbc161757b7f4be35b52205552.patch
-
-From: Stefan Hajnoczi <stefanha@redhat.com>
-Date: Wed, 27 Apr 2022 15:35:36 +0100
-Subject: [PATCH] virtio-scsi: fix ctrl and event handler functions in
- dataplane mode
-
-Commit f34e8d8b8d48d73f36a67b6d5e492ef9784b5012 ("virtio-scsi: prepare
-virtio_scsi_handle_cmd for dataplane") prepared the virtio-scsi cmd
-virtqueue handler function to be used in both the dataplane and
-non-datpalane code paths.
-
-It failed to convert the ctrl and event virtqueue handler functions,
-which are not designed to be called from the dataplane code path but
-will be since the ioeventfd is set up for those virtqueues when
-dataplane starts.
-
-Convert the ctrl and event virtqueue handler functions now so they
-operate correctly when called from the dataplane code path. Avoid code
-duplication by extracting this code into a helper function.
-
-Fixes: f34e8d8b8d48d73f36a67b6d5e492ef9784b5012 ("virtio-scsi: prepare virtio_scsi_handle_cmd for dataplane")
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
-Message-id: 20220427143541.119567-2-stefanha@redhat.com
-[Fixed s/by used/be used/ typo pointed out by Michael Tokarev
-<mjt@tls.msk.ru>.
---Stefan]
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---- a/hw/scsi/virtio-scsi.c
-+++ b/hw/scsi/virtio-scsi.c
-@@ -472,16 +472,32 @@ bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
- return progress;
- }
-
-+/*
-+ * If dataplane is configured but not yet started, do so now and return true on
-+ * success.
-+ *
-+ * Dataplane is started by the core virtio code but virtqueue handler functions
-+ * can also be invoked when a guest kicks before DRIVER_OK, so this helper
-+ * function helps us deal with manually starting ioeventfd in that case.
-+ */
-+static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
-+{
-+ if (!s->ctx || s->dataplane_started) {
-+ return false;
-+ }
-+
-+ virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
-+ return !s->dataplane_fenced;
-+}
-+
- static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
- {
- VirtIOSCSI *s = (VirtIOSCSI *)vdev;
-
-- if (s->ctx) {
-- virtio_device_start_ioeventfd(vdev);
-- if (!s->dataplane_fenced) {
-- return;
-- }
-+ if (virtio_scsi_defer_to_dataplane(s)) {
-+ return;
- }
-+
- virtio_scsi_acquire(s);
- virtio_scsi_handle_ctrl_vq(s, vq);
- virtio_scsi_release(s);
-@@ -720,12 +736,10 @@ static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
- /* use non-QOM casts in the data path */
- VirtIOSCSI *s = (VirtIOSCSI *)vdev;
-
-- if (s->ctx && !s->dataplane_started) {
-- virtio_device_start_ioeventfd(vdev);
-- if (!s->dataplane_fenced) {
-- return;
-- }
-+ if (virtio_scsi_defer_to_dataplane(s)) {
-+ return;
- }
-+
- virtio_scsi_acquire(s);
- virtio_scsi_handle_cmd_vq(s, vq);
- virtio_scsi_release(s);
-@@ -855,12 +869,10 @@ static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
- {
- VirtIOSCSI *s = VIRTIO_SCSI(vdev);
-
-- if (s->ctx) {
-- virtio_device_start_ioeventfd(vdev);
-- if (!s->dataplane_fenced) {
-- return;
-- }
-+ if (virtio_scsi_defer_to_dataplane(s)) {
-+ return;
- }
-+
- virtio_scsi_acquire(s);
- virtio_scsi_handle_event_vq(s, vq);
- virtio_scsi_release(s);
-GitLab
-
-From: Stefan Hajnoczi <stefanha@redhat.com>
-Date: Wed, 27 Apr 2022 15:35:37 +0100
-Subject: [PATCH] virtio-scsi: don't waste CPU polling the event virtqueue
-
-The virtio-scsi event virtqueue is not emptied by its handler function.
-This is typical for rx virtqueues where the device uses buffers when
-some event occurs (e.g. a packet is received, an error condition
-happens, etc).
-
-Polling non-empty virtqueues wastes CPU cycles. We are not waiting for
-new buffers to become available, we are waiting for an event to occur,
-so it's a misuse of CPU resources to poll for buffers.
-
-Introduce the new virtio_queue_aio_attach_host_notifier_no_poll() API,
-which is identical to virtio_queue_aio_attach_host_notifier() except
-that it does not poll the virtqueue.
-
-Before this patch the following command-line consumed 100% CPU in the
-IOThread polling and calling virtio_scsi_handle_event():
-
- $ qemu-system-x86_64 -M accel=kvm -m 1G -cpu host \
- --object iothread,id=iothread0 \
- --device virtio-scsi-pci,iothread=iothread0 \
- --blockdev file,filename=test.img,aio=native,cache.direct=on,node-name=drive0 \
- --device scsi-hd,drive=drive0
-
-After this patch CPU is no longer wasted.
-
-Reported-by: Nir Soffer <nsoffer@redhat.com>
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-Tested-by: Nir Soffer <nsoffer@redhat.com>
-Message-id: 20220427143541.119567-3-stefanha@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---- a/hw/scsi/virtio-scsi-dataplane.c
-+++ b/hw/scsi/virtio-scsi-dataplane.c
-@@ -138,7 +138,7 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
-
- aio_context_acquire(s->ctx);
- virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx);
-- virtio_queue_aio_attach_host_notifier(vs->event_vq, s->ctx);
-+ virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx);
-
- for (i = 0; i < vs->conf.num_queues; i++) {
- virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx);
---- a/hw/virtio/virtio.c
-+++ b/hw/virtio/virtio.c
-@@ -3534,6 +3534,19 @@ void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx)
- virtio_queue_host_notifier_aio_poll_end);
- }
-
-+/*
-+ * Same as virtio_queue_aio_attach_host_notifier() but without polling. Use
-+ * this for rx virtqueues and similar cases where the virtqueue handler
-+ * function does not pop all elements. When the virtqueue is left non-empty
-+ * polling consumes CPU cycles and should not be used.
-+ */
-+void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx)
-+{
-+ aio_set_event_notifier(ctx, &vq->host_notifier, true,
-+ virtio_queue_host_notifier_read,
-+ NULL, NULL);
-+}
-+
- void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx)
- {
- aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL, NULL);
---- a/include/hw/virtio/virtio.h
-+++ b/include/hw/virtio/virtio.h
-@@ -317,6 +317,7 @@ EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq);
- void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled);
- void virtio_queue_host_notifier_read(EventNotifier *n);
- void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx);
-+void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx);
- void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx);
- VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector);
- VirtQueue *virtio_vector_next_queue(VirtQueue *vq);
-GitLab
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-29 13:34:19 +0000