From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CDF34B44A8; Thu, 17 Sep 2026 15:42:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659731; cv=none; b=LgenNyz4an3llt1LvMLayoWg1xf88TOa7/vVC2HOLQihL3uUIpbWlgkc++SGOChWCv4y/3tay6z7GSjwHbEyJgG6qjgZ2yUd5fn26RJ0eTneUWMb18VCOR6lOv2tL9Kp9wMNnuOwGgY66U/aiyjEUCqgAH6fIkCApCj8IK/JDgM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659731; c=relaxed/simple; bh=xYKkCXTjDYtOKOgY1vQI+6YBk69wYkBVsT4u3afEeX0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jelf9jonuwRbRN6eThkIjBTp3SJUqK0da3rwJrFXQqScLaJmWj3xdiMcEEKtu1RMaUZM1AqnLrzxRKG8nhC5VvnJXQ+QOwSSuNVXvzP4VMmPP8QO11W+YUxzfahWBKGj+V1rZ7/l6xmqbvskd2I0uEom3USNbJigWXx8gVjdLGI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=njd3mwVX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="njd3mwVX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFC3B1F000FF; Thu, 17 Sep 2026 15:41:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789659720; bh=yih8uWyjteQbhBjCA9Si+bpXvGwnmkAyVJWMKjB+mvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=njd3mwVX28D4Hq8aqbrockfhmSdSJGe/hCKFOOEhTANDBBkM1aBr6KVVjBjCRsQIf tPYZjwxKchfyAUL5TRvG8dkLWIWksq9OwgdYjsY8KdAGJTy9ZTjpFMIePgVoM+mqgT ahaborj1C+5tNp2Gzwb5ZnFMVmcRd8Jcpg5xo/zA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Michael S. Tsirkin" , Jia Jia , Sasha Levin Subject: [PATCH 7.2 351/733] vhost: invalidate vring access on IOTLB transitions Date: Thu, 17 Sep 2026 16:10:59 +0100 Message-ID: <20260917151400.322542579@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jia Jia [ Upstream commit e4f4761879a230aa59e569102a6ab9851847d833 ] When VIRTIO_F_ACCESS_PLATFORM changes, cached vring pointers and IOTLB metadata are interpreted in a different address space. Keeping them across the transition can leave stale ring mappings in use. Clearing d->iotlb before taking the VQ locks also lets a worker observe a transient NULL d->iotlb and fall back to d->umem while translating a descriptor. Add a common vhost_clear_device_iotlb() helper for vhost-net and vhost-vsock. Take all VQ mutexes in index order before dropping the device-wide IOTLB, invalidate each VQ's cached ring access and metadata, clear pending IOTLB messages, and free the old table after the handoff. This serializes the transition with workers and prevents mixed address space mappings. On the first direct-to-IOTLB transition, invalidate the cached vring addresses. When an existing device IOTLB is replaced, preserve the GIOVA ring addresses and reset only the metadata cache. After clearing ACCESS_PLATFORM, userspace must configure the vring addresses for the new address mode. vhost_vq_invalidate_access() clears desc, avail, and used together. Treat the VQ as invalidated only when all three are NULL, since a single GIOVA address may legitimately be zero. Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API") Fixes: e13a6915a03f ("vhost/vsock: add IOTLB API support") Suggested-by: Michael S. Tsirkin Signed-off-by: Jia Jia Signed-off-by: Michael S. Tsirkin Message-ID: <20260828085721.57816-1-physicalmtea@gmail.com> Signed-off-by: Sasha Levin --- drivers/vhost/net.c | 2 ++ drivers/vhost/vhost.c | 57 ++++++++++++++++++++++++++++++++++++++++++- drivers/vhost/vhost.h | 1 + drivers/vhost/vsock.c | 2 ++ 4 files changed, 61 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 38d9c184082d0..4d9d7c2216ed5 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1696,6 +1696,8 @@ static int vhost_net_set_features(struct vhost_net *n, const u64 *features) if (virtio_features_test_bit(features, VIRTIO_F_ACCESS_PLATFORM)) { if (vhost_init_device_iotlb(&n->dev)) goto out_unlock; + } else { + vhost_clear_device_iotlb(&n->dev); } for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 269efad90369e..f9511be1fa43f 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -344,6 +344,17 @@ static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq) vq->meta_iotlb[j] = NULL; } +/* Caller must hold the virtqueue mutex. */ +static void vhost_vq_invalidate_access(struct vhost_virtqueue *vq) +{ + vq->desc = NULL; + vq->avail = NULL; + vq->used = NULL; + vq->log_used = false; + vq->log_addr = -1ull; + __vhost_vq_meta_reset(vq); +} + static void vhost_vq_meta_reset(struct vhost_dev *d) { int i; @@ -1914,6 +1925,13 @@ int vq_meta_prefetch(struct vhost_virtqueue *vq) { unsigned int num = vq->num; + /* + * vhost_vq_invalidate_access() clears all three addresses together. + * A single zero address may be a valid GIOVA in IOTLB mode. + */ + if (!vq->desc && !vq->avail && !vq->used) + return 0; + if (!vq->iotlb) return 1; @@ -2283,6 +2301,40 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg } EXPORT_SYMBOL_GPL(vhost_vring_ioctl); +/* Caller must hold the device mutex. */ +void vhost_clear_device_iotlb(struct vhost_dev *d) +{ + struct vhost_iotlb *iotlb; + int i; + + iotlb = d->iotlb; + if (!iotlb) + return; + + vhost_dev_lock_vqs(d); + + /* + * vhost_dev_lock_vqs() takes all VQ mutexes in index order. Drop the + * device-wide view while they are held, then clear each per-VQ view + * and its cached ring access before releasing the locks. Workers + * cannot observe a mixed address-space state during this handoff. + */ + d->iotlb = NULL; + + for (i = 0; i < d->nvqs; ++i) { + struct vhost_virtqueue *vq = d->vqs[i]; + + vq->iotlb = NULL; + vhost_vq_invalidate_access(vq); + } + + vhost_dev_unlock_vqs(d); + vhost_clear_msg(d); + vhost_iotlb_free(iotlb); + wake_up_interruptible_poll(&d->wait, EPOLLIN | EPOLLRDNORM); +} +EXPORT_SYMBOL_GPL(vhost_clear_device_iotlb); + int vhost_init_device_iotlb(struct vhost_dev *d) { struct vhost_iotlb *niotlb, *oiotlb; @@ -2303,7 +2355,10 @@ int vhost_init_device_iotlb(struct vhost_dev *d) mutex_lock(&vq->mutex); vq->iotlb = niotlb; - __vhost_vq_meta_reset(vq); + if (oiotlb) + __vhost_vq_meta_reset(vq); + else + vhost_vq_invalidate_access(vq); mutex_unlock(&vq->mutex); } diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 0192ade6e7491..3c75e80893730 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -277,6 +277,7 @@ ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, int noblock); ssize_t vhost_chr_write_iter(struct vhost_dev *dev, struct iov_iter *from); +void vhost_clear_device_iotlb(struct vhost_dev *d); int vhost_init_device_iotlb(struct vhost_dev *d); void vhost_iotlb_map_free(struct vhost_iotlb *iotlb, diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 9aaab6bb8061c..abed1fbcf66cc 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -868,6 +868,8 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features) if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { if (vhost_init_device_iotlb(&vsock->dev)) goto err; + } else { + vhost_clear_device_iotlb(&vsock->dev); } vsock->seqpacket_allow = features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET); -- 2.53.0