linux/drivers/virtio, branch v5.1

virtio: Honour 'may_reduce_num' in vring_create_virtqueue

2019-04-08T21:05:52Z

vring_create_virtqueue() allows the caller to specify via the may_reduce_num parameter whether the vring code is allowed to allocate a smaller ring than specified. However, the split ring allocation code tries to allocate a smaller ring on allocation failure regardless of what the caller specified. This may cause trouble for e.g. virtio-pci in legacy mode, which does not support ring resizing. (The packed ring code does not resize in any case.) Let's fix this by bailing out immediately in the split ring code if the requested size cannot be allocated and may_reduce_num has not been specified. While at it, fix a typo in the usage instructions. Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Reviewed-by: Halil Pasic Reviewed-by: Jens Freimann

virtio_pci: fix a NULL pointer reference in vp_del_vqs

2019-04-08T12:40:58Z

If the msix_affinity_masks is alloced failed, then we'll try to free some resources in vp_free_vectors() that may access it directly. We met the following stack in our production: [ 29.296767] BUG: unable to handle kernel NULL pointer dereference at (null) [ 29.311151] IP: [] vp_free_vectors+0x6a/0x150 [virtio_pci] [ 29.324787] PGD 0 [ 29.333224] Oops: 0000 [#1] SMP [...] [ 29.425175] RIP: 0010:[] [] vp_free_vectors+0x6a/0x150 [virtio_pci] [ 29.441405] RSP: 0018:ffff9a55c2dcfa10 EFLAGS: 00010206 [ 29.453491] RAX: 0000000000000000 RBX: ffff9a55c322c400 RCX: 0000000000000000 [ 29.467488] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9a55c322c400 [ 29.481461] RBP: ffff9a55c2dcfa20 R08: 0000000000000000 R09: ffffc1b6806ff020 [ 29.495427] R10: 0000000000000e95 R11: 0000000000aaaaaa R12: 0000000000000000 [ 29.509414] R13: 0000000000010000 R14: ffff9a55bd2d9e98 R15: ffff9a55c322c400 [ 29.523407] FS: 00007fdcba69f8c0(0000) GS:ffff9a55c2840000(0000) knlGS:0000000000000000 [ 29.538472] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.551621] CR2: 0000000000000000 CR3: 000000003ce52000 CR4: 00000000003607a0 [ 29.565886] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.580055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.594122] Call Trace: [ 29.603446] [] vp_request_msix_vectors+0xe2/0x260 [virtio_pci] [ 29.618017] [] vp_try_to_find_vqs+0x95/0x3b0 [virtio_pci] [ 29.632152] [] vp_find_vqs+0x37/0xb0 [virtio_pci] [ 29.645582] [] init_vq+0x153/0x260 [virtio_blk] [ 29.658831] [] virtblk_probe+0xe8/0x87f [virtio_blk] [...] Cc: Gonglei Signed-off-by: Longpeng Signed-off-by: Michael S. Tsirkin Reviewed-by: Gonglei

virtio: hint if callbacks surprisingly might sleep

2019-03-06T16:19:57Z

A virtio transport is free to implement some of the callbacks in virtio_config_ops in a matter that they cannot be called from atomic context (e.g. virtio-ccw, which maps a lot of the callbacks to channel I/O, which is an inherently asynchronous mechanism). This can be very surprising for developers using the much more common virtio-pci transport, just to find out that things break when used on s390. The documentation for virtio_config_ops now contains a comment explaining this, but it makes sense to add a might_sleep() annotation to various wrapper functions in the virtio core to avoid surprises later. Note that annotations are NOT added to two classes of calls: - direct calls from device drivers (all current callers should be fine, however) - calls which clearly won't be made from atomic context (such as those ultimately coming in via the driver core) Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin

virtio_balloon: remove the unnecessary 0-initialization

2019-03-06T16:19:33Z

We've changed to kzalloc the vb struct, so no need to 0-initialize this field one more time. Signed-off-by: Wei Wang Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck

virtio-balloon: improve update_balloon_size_func

2019-03-06T16:19:33Z

There is no need to update the balloon actual register when there is no ballooning request. This patch avoids update_balloon_size when diff is 0. Signed-off-by: Wei Wang Reviewed-by: Cornelia Huck Reviewed-by: Halil Pasic Signed-off-by: Michael S. Tsirkin

virtio: Introduce virtio_max_dma_size()

2019-03-06T16:19:15Z

This function returns the maximum segment size for a single dma transaction of a virtio device. The possible limit comes from the SWIOTLB implementation in the Linux kernel, that has an upper limit of (currently) 256kb of contiguous memory it can map. Other DMA-API implementations might also have limits. Use the new dma_max_mapping_size() function to determine the maximum mapping size when DMA-API is in use for virtio. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Christoph Hellwig Signed-off-by: Joerg Roedel Signed-off-by: Michael S. Tsirkin

virtio: drop internal struct from UAPI

2019-02-05T20:29:48Z

There's no reason to expose struct vring_packed in UAPI - if we do we won't be able to change or drop it, and it's not part of any interface. Let's move it to virtio_ring.c Cc: Tiwei Bie Signed-off-by: Michael S. Tsirkin

virtio: support VIRTIO_F_ORDER_PLATFORM

2019-01-24T15:15:42Z

This patch introduces the support for VIRTIO_F_ORDER_PLATFORM. If this feature is negotiated, the driver must use the barriers suitable for hardware devices. Otherwise, the device and driver are assumed to be implemented in software, that is they can be assumed to run on identical CPUs in an SMP configuration. Thus a weaker form of memory barriers is sufficient to yield better performance. It is recommended that an add-in card based PCI device offers this feature for portability. The device will fail to operate further or will operate in a slower emulation mode if this feature is offered but not accepted. Signed-off-by: Tiwei Bie Signed-off-by: Michael S. Tsirkin

virtio-balloon: tweak config_changed implementation

2019-01-15T01:15:20Z

virtio-ccw has deadlock issues with reading the config space inside the interrupt context, so we tweak the virtballoon_changed implementation by moving the config read operations into the related workqueue contexts. The config_read_bitmap is used as a flag to the workqueue callbacks about the related config fields that need to be read. The cmd_id_received is also renamed to cmd_id_received_cache, and the value should be obtained via virtio_balloon_cmd_id_received. Reported-by: Christian Borntraeger Signed-off-by: Wei Wang Reviewed-by: Cornelia Huck Reviewed-by: Halil Pasic Signed-off-by: Michael S. Tsirkin Cc: stable@vger.kernel.org Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Tested-by: Christian Borntraeger

virtio: don't allocate vqs when names[i] = NULL

2019-01-15T01:15:19Z

Some vqs may not need to be allocated when their related feature bits are disabled. So callers may pass in such vqs with "names = NULL". Then we skip such vq allocations. Signed-off-by: Wei Wang Signed-off-by: Michael S. Tsirkin Signed-off-by: Wei Wang Signed-off-by: Wei Wang Reviewed-by: Cornelia Huck Cc: stable@vger.kernel.org Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")