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Subject[PATCH] s390: protvirt: virtio: Refuse device without IOMMU
Date
Protected Virtualisation protects the memory of the guest and
do not allow a the host to access all of its memory.

Let's refuse a VIRTIO device which does not use IOMMU
protected access.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
drivers/s390/virtio/virtio_ccw.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 5730572b52cd..06ffbc96587a 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -986,6 +986,11 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
if (!ccw)
return;

+ /* Protected Virtualisation guest needs IOMMU */
+ if (is_prot_virt_guest() &&
+ !__virtio_test_bit(vdev, VIRTIO_F_IOMMU_PLATFORM))
+ status &= ~VIRTIO_CONFIG_S_FEATURES_OK;
+
/* Write the status to the host. */
vcdev->dma_area->status = status;
ccw->cmd_code = CCW_CMD_WRITE_STATUS;
--
2.25.1
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