152 lines
5.4 KiB
Diff
152 lines
5.4 KiB
Diff
From 0d022f741ab510b52453bb9e9e07b968e7d5e0df Mon Sep 17 00:00:00 2001
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From: Xueming Li <xuemingl@nvidia.com>
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Date: Mon, 7 Feb 2022 15:19:29 +0800
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Subject: [PATCH 2/2] vhost-user: fix VirtQ notifier cleanup
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When vhost-user device cleanup, remove notifier MR and munmaps notifier
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address in the event-handling thread, VM CPU thread writing the notifier
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in concurrent fails with an error of accessing invalid address. It
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happens because MR is still being referenced and accessed in another
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thread while the underlying notifier mmap address is being freed and
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becomes invalid.
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This patch calls RCU and munmap notifiers in the callback after the
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memory flatview update finish.
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Fixes: 44866521bd6e ("vhost-user: support registering external host notifiers")
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Xueming Li <xuemingl@nvidia.com>
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Message-Id: <20220207071929.527149-3-xuemingl@nvidia.com>
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Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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(cherry picked from commit 0b0af4d62f7002b31cd7b2762b26d2fcb76bb2ba)
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---
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hw/virtio/vhost-user.c | 48 ++++++++++++++++++++--------------
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include/hw/virtio/vhost-user.h | 2 ++
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2 files changed, 31 insertions(+), 19 deletions(-)
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diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
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index 7b21e09723..42a9e16cd9 100644
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--- a/hw/virtio/vhost-user.c
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+++ b/hw/virtio/vhost-user.c
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@@ -26,6 +26,7 @@
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#include "migration/postcopy-ram.h"
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#include "migration/register.h"
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#include "trace.h"
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+#include "exec/ramblock.h"
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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@@ -1145,15 +1146,26 @@ static int vhost_user_set_vring_num(struct vhost_dev *dev,
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return vhost_set_vring(dev, VHOST_USER_SET_VRING_NUM, ring);
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}
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-static void vhost_user_host_notifier_remove(struct vhost_dev *dev,
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- int queue_idx)
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+static void vhost_user_host_notifier_free(VhostUserHostNotifier *n)
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{
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- struct vhost_user *u = dev->opaque;
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- VhostUserHostNotifier *n = &u->user->notifier[queue_idx];
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- VirtIODevice *vdev = dev->vdev;
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+ assert(n && n->unmap_addr);
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+ munmap(n->unmap_addr, qemu_real_host_page_size);
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+ n->unmap_addr = NULL;
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+}
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+
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+static void vhost_user_host_notifier_remove(VhostUserState *user,
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+ VirtIODevice *vdev, int queue_idx)
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+{
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+ VhostUserHostNotifier *n = &user->notifier[queue_idx];
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if (n->addr) {
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- virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, false);
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+ if (vdev) {
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+ virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, false);
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+ }
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+ assert(!n->unmap_addr);
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+ n->unmap_addr = n->addr;
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+ n->addr = NULL;
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+ call_rcu(n, vhost_user_host_notifier_free, rcu);
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}
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}
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@@ -1192,8 +1204,9 @@ static int vhost_user_get_vring_base(struct vhost_dev *dev,
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.payload.state = *ring,
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.hdr.size = sizeof(msg.payload.state),
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};
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+ struct vhost_user *u = dev->opaque;
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- vhost_user_host_notifier_remove(dev, ring->index);
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+ vhost_user_host_notifier_remove(u->user, dev->vdev, ring->index);
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if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
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return -1;
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@@ -1488,12 +1501,7 @@ static int vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev,
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n = &user->notifier[queue_idx];
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- if (n->addr) {
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- virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, false);
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- object_unparent(OBJECT(&n->mr));
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- munmap(n->addr, page_size);
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- n->addr = NULL;
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- }
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+ vhost_user_host_notifier_remove(user, vdev, queue_idx);
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if (area->u64 & VHOST_USER_VRING_NOFD_MASK) {
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return 0;
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@@ -1512,9 +1520,12 @@ static int vhost_user_slave_handle_vring_host_notifier(struct vhost_dev *dev,
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name = g_strdup_printf("vhost-user/host-notifier@%p mmaps[%d]",
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user, queue_idx);
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- if (!n->mr.ram) /* Don't init again after suspend. */
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+ if (!n->mr.ram) { /* Don't init again after suspend. */
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memory_region_init_ram_device_ptr(&n->mr, OBJECT(vdev), name,
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page_size, addr);
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+ } else {
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+ n->mr.ram_block->host = addr;
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+ }
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g_free(name);
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if (virtio_queue_set_host_notifier_mr(vdev, queue_idx, &n->mr, true)) {
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@@ -2492,17 +2503,16 @@ bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp)
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void vhost_user_cleanup(VhostUserState *user)
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{
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int i;
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+ VhostUserHostNotifier *n;
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if (!user->chr) {
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return;
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}
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memory_region_transaction_begin();
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for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
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- if (user->notifier[i].addr) {
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- object_unparent(OBJECT(&user->notifier[i].mr));
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- munmap(user->notifier[i].addr, qemu_real_host_page_size);
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- user->notifier[i].addr = NULL;
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- }
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+ n = &user->notifier[i];
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+ vhost_user_host_notifier_remove(user, NULL, i);
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+ object_unparent(OBJECT(&n->mr));
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}
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memory_region_transaction_commit();
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user->chr = NULL;
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diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
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index f6012b2078..e44a41bb70 100644
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--- a/include/hw/virtio/vhost-user.h
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+++ b/include/hw/virtio/vhost-user.h
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@@ -12,8 +12,10 @@
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#include "hw/virtio/virtio.h"
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typedef struct VhostUserHostNotifier {
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+ struct rcu_head rcu;
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MemoryRegion mr;
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void *addr;
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+ void *unmap_addr;
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} VhostUserHostNotifier;
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typedef struct VhostUserState {
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--
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2.27.0
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