Messages in this thread Patch in this message | | | Date | Tue, 19 Jul 2022 10:02:56 +0000 | Subject | [PATCH] virtio: Force DMA restricted devices through DMA API | From | Keir Fraser <> |
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If virtio devices are tagged for "restricted-dma-pool", then that pool should be used for virtio ring setup, via the DMA API.
In particular, this fixes virtio_balloon for ARM PKVM, where the usual workaround of setting VIRTIO_F_ACCESS_PLATFORM in the virtio device doesn't work because the virtio_balloon driver clears the flag. This seems a more robust fix than fiddling the flag again.
Signed-off-by: Keir Fraser <keirf@google.com> --- drivers/virtio/virtio_ring.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index a5ec724c01d8..12be2607c648 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -12,6 +12,7 @@ #include <linux/hrtimer.h> #include <linux/dma-mapping.h> #include <linux/spinlock.h> +#include <linux/swiotlb.h> #include <xen/xen.h> #ifdef DEBUG @@ -248,6 +249,13 @@ static bool vring_use_dma_api(struct virtio_device *vdev) if (!virtio_has_dma_quirk(vdev)) return true; + /* If the device is configured to use a DMA restricted pool, + * we had better use it. + */ + if (IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL) && + is_swiotlb_for_alloc(vdev->dev.parent)) + return true; + /* Otherwise, we are left to guess. */ /* * In theory, it's possible to have a buggy QEMU-supposed -- 2.37.0.170.g444d1eabd0-goog
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