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From: Will Deacon <will@kernel.org>
To: virtualization@lists.linux-foundation.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	Marc Zyngier <maz@kernel.org>,
	Quentin Perret <qperret@google.com>,
	linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>
Subject: [PATCH] virtio_ring: Fix querying of maximum DMA mapping size for virtio device
Date: Wed,  1 Dec 2021 11:20:18 +0000	[thread overview]
Message-ID: <20211201112018.25276-1-will@kernel.org> (raw)

virtio_max_dma_size() returns the maximum DMA mapping size of the virtio
device by querying dma_max_mapping_size() for the device when the DMA
API is in use for the vring. Unfortunately, the device passed is
initialised by register_virtio_device() and does not inherit the DMA
configuration from its parent, resulting in SWIOTLB errors when bouncing
is enabled and the default 256K mapping limit (IO_TLB_SEGSIZE) is not
respected:

  | virtio-pci 0000:00:01.0: swiotlb buffer is full (sz: 294912 bytes), total 1024 (slots), used 725 (slots)

Follow the pattern used elsewhere in the virtio_ring code when calling
into the DMA layer and pass the parent device to dma_max_mapping_size()
instead.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 drivers/virtio/virtio_ring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6d2614e34470..028b05d44546 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev)
 	size_t max_segment_size = SIZE_MAX;
 
 	if (vring_use_dma_api(vdev))
-		max_segment_size = dma_max_mapping_size(&vdev->dev);
+		max_segment_size = dma_max_mapping_size(vdev->dev.parent);
 
 	return max_segment_size;
 }
-- 
2.34.0.rc2.393.gf8c9666880-goog

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WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: virtualization@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	Marc Zyngier <maz@kernel.org>,
	Quentin Perret <qperret@google.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>
Subject: [PATCH] virtio_ring: Fix querying of maximum DMA mapping size for virtio device
Date: Wed,  1 Dec 2021 11:20:18 +0000	[thread overview]
Message-ID: <20211201112018.25276-1-will@kernel.org> (raw)

virtio_max_dma_size() returns the maximum DMA mapping size of the virtio
device by querying dma_max_mapping_size() for the device when the DMA
API is in use for the vring. Unfortunately, the device passed is
initialised by register_virtio_device() and does not inherit the DMA
configuration from its parent, resulting in SWIOTLB errors when bouncing
is enabled and the default 256K mapping limit (IO_TLB_SEGSIZE) is not
respected:

  | virtio-pci 0000:00:01.0: swiotlb buffer is full (sz: 294912 bytes), total 1024 (slots), used 725 (slots)

Follow the pattern used elsewhere in the virtio_ring code when calling
into the DMA layer and pass the parent device to dma_max_mapping_size()
instead.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 drivers/virtio/virtio_ring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6d2614e34470..028b05d44546 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -268,7 +268,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev)
 	size_t max_segment_size = SIZE_MAX;
 
 	if (vring_use_dma_api(vdev))
-		max_segment_size = dma_max_mapping_size(&vdev->dev);
+		max_segment_size = dma_max_mapping_size(vdev->dev.parent);
 
 	return max_segment_size;
 }
-- 
2.34.0.rc2.393.gf8c9666880-goog


             reply	other threads:[~2021-12-01 11:20 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-01 11:20 Will Deacon [this message]
2021-12-01 11:20 ` [PATCH] virtio_ring: Fix querying of maximum DMA mapping size for virtio device Will Deacon
2021-12-02  3:12 ` Jason Wang
2021-12-02  3:12   ` Jason Wang
2021-12-03 15:50 ` Suzuki K Poulose

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