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From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: joro@8bytes.org
Cc: eric.auger@redhat.com, iommu@lists.linux.dev, will@kernel.org,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	virtualization@lists.linux-foundation.org
Subject: [PATCH] iommu/virtio: Advertise IOMMU_CAP_CACHE_COHERENCY
Date: Thu, 14 Jul 2022 12:11:01 +0100	[thread overview]
Message-ID: <20220714111059.708735-1-jean-philippe@linaro.org> (raw)

Fix virtio-iommu interaction with VFIO, as VFIO now requires
IOMMU_CAP_CACHE_COHERENCY. virtio-iommu does not support non-cacheable
mappings, and always expects to be called with IOMMU_CACHE.

Fixes: e8ae0e140c05 ("vfio: Require that devices support DMA cache coherence")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/virtio-iommu.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 25be4b822aa0..bf340d779c10 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -1006,7 +1006,18 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
 	return iommu_fwspec_add_ids(dev, args->args, 1);
 }
 
+static bool viommu_capable(enum iommu_cap cap)
+{
+	switch (cap) {
+	case IOMMU_CAP_CACHE_COHERENCY:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static struct iommu_ops viommu_ops = {
+	.capable		= viommu_capable,
 	.domain_alloc		= viommu_domain_alloc,
 	.probe_device		= viommu_probe_device,
 	.probe_finalize		= viommu_probe_finalize,
-- 
2.36.1

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             reply	other threads:[~2022-07-14 11:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-14 11:11 Jean-Philippe Brucker [this message]
2022-07-14 12:01 ` [PATCH] iommu/virtio: Advertise IOMMU_CAP_CACHE_COHERENCY Robin Murphy
2022-07-14 13:00   ` Jean-Philippe Brucker
2022-07-14 13:39     ` Robin Murphy
2022-07-22 12:15       ` Jean-Philippe Brucker

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