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135 lines
5.0 KiB
135 lines
5.0 KiB
From 893dffb820973361bcef33612a6b924554a856c1 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
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Date: Thu, 21 Jul 2022 15:38:55 +0200
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Subject: [PATCH 13/32] vhost: Check for queue full at vhost_svq_add
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Eugenio Pérez <eperezma@redhat.com>
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RH-MergeRequest: 108: Net Control Virtqueue shadow Support
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RH-Commit: [13/27] d4bd8299fb7733a1e190618dfc92b4b53b7bbeb3 (eperezmartin/qemu-kvm)
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RH-Bugzilla: 1939363
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RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>
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RH-Acked-by: Cindy Lu <lulu@redhat.com>
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/1939363
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Upstream Status: git://git.qemu.org/qemu.git
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commit f20b70eb5a68cfd8fef74a13ccdd494ef1cb0221
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Author: Eugenio Pérez <eperezma@redhat.com>
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Date: Wed Jul 20 08:59:32 2022 +0200
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vhost: Check for queue full at vhost_svq_add
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The series need to expose vhost_svq_add with full functionality,
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including checking for full queue.
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Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
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---
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hw/virtio/vhost-shadow-virtqueue.c | 59 +++++++++++++++++-------------
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1 file changed, 33 insertions(+), 26 deletions(-)
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diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
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index e3fc3c2658..1d2bab287b 100644
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--- a/hw/virtio/vhost-shadow-virtqueue.c
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+++ b/hw/virtio/vhost-shadow-virtqueue.c
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@@ -233,21 +233,29 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
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* Add an element to a SVQ.
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*
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* The caller must check that there is enough slots for the new element. It
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- * takes ownership of the element: In case of failure, it is free and the SVQ
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- * is considered broken.
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+ * takes ownership of the element: In case of failure not ENOSPC, it is free.
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+ *
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+ * Return -EINVAL if element is invalid, -ENOSPC if dev queue is full
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*/
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-static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
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+static int vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
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{
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unsigned qemu_head;
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- bool ok = vhost_svq_add_split(svq, elem, &qemu_head);
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+ unsigned ndescs = elem->in_num + elem->out_num;
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+ bool ok;
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+
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+ if (unlikely(ndescs > vhost_svq_available_slots(svq))) {
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+ return -ENOSPC;
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+ }
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+
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+ ok = vhost_svq_add_split(svq, elem, &qemu_head);
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if (unlikely(!ok)) {
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g_free(elem);
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- return false;
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+ return -EINVAL;
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}
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svq->ring_id_maps[qemu_head] = elem;
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vhost_svq_kick(svq);
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- return true;
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+ return 0;
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}
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/**
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@@ -274,7 +282,7 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
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while (true) {
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VirtQueueElement *elem;
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- bool ok;
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+ int r;
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if (svq->next_guest_avail_elem) {
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elem = g_steal_pointer(&svq->next_guest_avail_elem);
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@@ -286,25 +294,24 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
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break;
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}
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- if (elem->out_num + elem->in_num > vhost_svq_available_slots(svq)) {
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- /*
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- * This condition is possible since a contiguous buffer in GPA
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- * does not imply a contiguous buffer in qemu's VA
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- * scatter-gather segments. If that happens, the buffer exposed
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- * to the device needs to be a chain of descriptors at this
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- * moment.
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- *
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- * SVQ cannot hold more available buffers if we are here:
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- * queue the current guest descriptor and ignore further kicks
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- * until some elements are used.
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- */
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- svq->next_guest_avail_elem = elem;
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- return;
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- }
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-
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- ok = vhost_svq_add(svq, elem);
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- if (unlikely(!ok)) {
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- /* VQ is broken, just return and ignore any other kicks */
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+ r = vhost_svq_add(svq, elem);
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+ if (unlikely(r != 0)) {
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+ if (r == -ENOSPC) {
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+ /*
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+ * This condition is possible since a contiguous buffer in
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+ * GPA does not imply a contiguous buffer in qemu's VA
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+ * scatter-gather segments. If that happens, the buffer
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+ * exposed to the device needs to be a chain of descriptors
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+ * at this moment.
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+ *
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+ * SVQ cannot hold more available buffers if we are here:
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+ * queue the current guest descriptor and ignore kicks
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+ * until some elements are used.
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+ */
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+ svq->next_guest_avail_elem = elem;
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+ }
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+
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+ /* VQ is full or broken, just return and ignore kicks */
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return;
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}
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}
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--
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2.31.1
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