From: Keir Fraser <keirf@google.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
Cc: kernel-team@android.com, Keir Fraser <keirf@google.com>,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: [PATCH] virtio: Force DMA restricted devices through DMA API
Date: Tue, 19 Jul 2022 10:02:56 +0000 [thread overview]
Message-ID: <20220719100256.419780-1-keirf@google.com> (raw)
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
next reply other threads:[~2022-07-19 10:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 10:02 Keir Fraser [this message]
2022-07-19 11:56 ` [PATCH] virtio: Force DMA restricted devices through DMA API Michael S. Tsirkin
2022-07-19 14:05 ` Keir Fraser
2022-07-19 21:31 ` Michael S. Tsirkin
2022-07-19 15:23 ` Christoph Hellwig
2022-07-19 15:46 ` Keir Fraser
2022-07-19 15:51 ` Christoph Hellwig
2022-07-19 16:11 ` Keir Fraser
2022-07-20 5:16 ` Christoph Hellwig
2022-07-20 6:59 ` Michael S. Tsirkin
2022-07-20 8:27 ` Keir Fraser
2022-07-20 9:58 ` Michael S. Tsirkin
2022-07-21 7:37 ` Keir Fraser
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