kernel/linux.git/drivers/s390/virtio, branch v6.12.80

s390/virtio_ccw: Don't allocate/assign airqs for non-existing queues

2025-04-20T08:15:59+00:00

commit 2ccd42b959aaf490333dbd3b9b102eaf295c036a upstream. If we finds a vq without a name in our input array in virtio_ccw_find_vqs(), we treat it as "non-existing" and set the vq pointer to NULL; we will not call virtio_ccw_setup_vq() to allocate/setup a vq. Consequently, we create only a queue if it actually exists (name != NULL) and assign an incremental queue index to each such existing queue. However, in virtio_ccw_register_adapter_ind()->get_airq_indicator() we will not ignore these "non-existing queues", but instead assign an airq indicator to them. Besides never releasing them in virtio_ccw_drop_indicators() (because there is no virtqueue), the bigger issue seems to be that there will be a disagreement between the device and the Linux guest about the airq indicator to be used for notifying a queue, because the indicator bit for adapter I/O interrupt is derived from the queue index. The virtio spec states under "Setting Up Two-Stage Queue Indicators": ... indicator contains the guest address of an area wherein the indicators for the devices are contained, starting at bit_nr, one bit per virtqueue of the device. And further in "Notification via Adapter I/O Interrupts": For notifying the driver of virtqueue buffers, the device sets the bit in the guest-provided indicator area at the corresponding offset. For example, QEMU uses in virtio_ccw_notify() the queue index (passed as "vector") to select the relevant indicator bit. If a queue does not exist, it does not have a corresponding indicator bit assigned, because it effectively doesn't have a queue index. Using a virtio-balloon-ccw device under QEMU with free-page-hinting disabled ("free-page-hint=off") but free-page-reporting enabled ("free-page-reporting=on") will result in free page reporting not working as expected: in the virtio_balloon driver, we'll be stuck forever in virtballoon_free_page_report()->wait_event(), because the waitqueue will not be woken up as the notification from the device is lost: it would use the wrong indicator bit. Free page reporting stops working and we get splats (when configured to detect hung wqs) like: INFO: task kworker/1:3:463 blocked for more than 61 seconds. Not tainted 6.14.0 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:3 [...] Workqueue: events page_reporting_process Call Trace: [<000002f404e6dfb2>] __schedule+0x402/0x1640 [<000002f404e6f22e>] schedule+0x3e/0xe0 [<000002f3846a88fa>] virtballoon_free_page_report+0xaa/0x110 [virtio_balloon] [<000002f40435c8a4>] page_reporting_process+0x2e4/0x740 [<000002f403fd3ee2>] process_one_work+0x1c2/0x400 [<000002f403fd4b96>] worker_thread+0x296/0x420 [<000002f403fe10b4>] kthread+0x124/0x290 [<000002f403f4e0dc>] __ret_from_fork+0x3c/0x60 [<000002f404e77272>] ret_from_fork+0xa/0x38 There was recently a discussion [1] whether the "holes" should be treated differently again, effectively assigning also non-existing queues a queue index: that should also fix the issue, but requires other workarounds to not break existing setups. Let's fix it without affecting existing setups for now by properly ignoring the non-existing queues, so the indicator bits will match the queue indexes. [1] https://lore.kernel.org/all/cover.1720611677.git.mst@redhat.com/ Fixes: a229989d975e ("virtio: don't allocate vqs when names[i] = NULL") Reported-by: Chandra Merla Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand Tested-by: Thomas Huth Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Acked-by: Michael S. Tsirkin Acked-by: Christian Borntraeger Link: https://lore.kernel.org/r/20250402203621.940090-1-david@redhat.com Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman

s390/virtio_ccw: Fix dma_parm pointer not set up

2024-12-05T13:01:10+00:00

[ Upstream commit 14c7579376279e507e52bf022192b46097a55377 ] At least since commit 334304ac2bac ("dma-mapping: don't return errors from dma_set_max_seg_size") setting up device.dma_parms is basically mandated by the DMA API. As of now Channel (CCW) I/O in general does not utilize the DMA API, except for virtio. For virtio-ccw however the common virtio DMA infrastructure is such that most of the DMA stuff hinges on the virtio parent device, which is a CCW device. So lets set up the dma_parms pointer for the CCW parent device and hope for the best! Fixes: 334304ac2bac ("dma-mapping: don't return errors from dma_set_max_seg_size") Reported-by: Marc Hartmayer Reviewed-by: Eric Farman Reviewed-by: Cornelia Huck Tested-by: Marc Hartmayer Link: https://lore.kernel.org/r/20241007201030.204028-1-pasic@linux.ibm.com Signed-off-by: Halil Pasic Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

virtio: rename find_vqs_info() op to find_vqs()

2024-07-17T09:20:57+00:00

Since the original find_vqs() is no longer present, rename find_vqs_info() back to find_vqs(). Signed-off-by: Jiri Pirko Message-Id: <20240708074814.1739223-10-jiri@resnulli.us> Signed-off-by: Michael S. Tsirkin

virtio: convert find_vqs() op implementations to find_vqs_info()

2024-07-17T09:20:57+00:00

Convert existing find_vqs() transport implementations to use find_vqs_info() config op. Signed-off-by: Jiri Pirko Message-Id: <20240708074814.1739223-7-jiri@resnulli.us> Signed-off-by: Michael S. Tsirkin

s390/virtio_ccw: Fix config change notifications

2024-06-17T19:49:01+00:00

Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API") broke configuration change notifications for virtio-ccw by putting the DMA address of *indicatorp directly into ccw->cda disregarding the fact that if !!(vcdev->is_thinint) then the function virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value with the address of the virtio_thinint_area so it can actually set up the adapter interrupts via CCW_CMD_SET_IND_ADAPTER. Thus we end up pointing to the wrong object for both CCW_CMD_SET_IND if setting up the adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless whether it succeeds or fails. To fix this, let us save away the dma address of *indicatorp in a local variable, and copy it to ccw->cda after the "vcdev->is_thinint" branch. Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API") Reported-by: Boqiao Fu Reported-by: Sebastian Mitterle Closes: https://issues.redhat.com/browse/RHEL-39983 Tested-by: Thomas Huth Reviewed-by: Eric Farman Signed-off-by: Halil Pasic Link: https://lore.kernel.org/r/20240611214716.1002781-1-pasic@linux.ibm.com Signed-off-by: Vasily Gorbik

s390/virtio_ccw: avoid converting dma addresses / handles

2024-03-13T08:23:46+00:00

Instead of converting virtual to physical addresses with the virt_to_dma*() functions, use dma addresses as provided by DMA API and only add offsets to these addresses. This makes sure that address conversion is only done by the DMA API. Signed-off-by: Halil Pasic Reviewed-by: Eric Farman Signed-off-by: Heiko Carstens

s390/virtio_ccw: use DMA handle from DMA API

2024-03-13T08:23:46+00:00

Change and use ccw_device_dma_zalloc() so it returns a virtual address like before, which can be used to access data. However also pass a new dma32_t pointer type handle, which correlates to the returned virtual address. This pointer is used to directly pass/set the DMA handle as returned by the DMA API. Signed-off-by: Halil Pasic Reviewed-by: Eric Farman Signed-off-by: Heiko Carstens

s390/virtio_ccw: fix virtual vs physical address confusion

2024-03-13T08:23:46+00:00

Fix virtual vs physical address confusion and use new dma types and helper functions to allow for type checking. This does not fix a bug since virtual and physical address spaces are currently the same. Signed-off-by: Halil Pasic Reviewed-by: Eric Farman Signed-off-by: Heiko Carstens

s390/airq: remove lsi_mask from airq_struct

2023-08-30T09:03:28+00:00

Remove the field `lsi_mask` from `struct airq_struct` as it is not utilized for any adapter interrupt, other than setting it to the default value of 0xff. Because nobody is using this functionality, all it does is cost a little bit of time with each delivered adapter interrupt. Reviewed-by: Michael Mueller Tested-by: Michael Mueller Acked-by: Peter Oberparleiter Signed-off-by: Benjamin Block Signed-off-by: Heiko Carstens

virtio: add VIRTIO_F_NOTIFICATION_DATA feature support

2023-04-21T07:02:35+00:00

According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature indicates that the driver passes extra data along with the queue notifications. In a split queue case, the extra data is 16-bit available index. In a packed queue case, the extra data is 1-bit wrap counter and 15-bit available index. Add support for this feature for MMIO, channel I/O and modern PCI transports. Signed-off-by: Viktor Prutyanov Acked-by: Jason Wang Reviewed-by: Xuan Zhuo Message-Id: <20230413081855.36643-2-alvaro.karsz@solid-run.com> Signed-off-by: Michael S. Tsirkin