Re: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU
From: Cornelia Huck <cohuck@redhat.com>
Date: 2020-06-10 13:24:48
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On Wed, 10 Jun 2020 15:11:51 +0200 Pierre Morel [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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; +
set_status seems like an odd place to look at features; shouldn't that rather be done in finalize_features?
/* Write the status to the host. */ vcdev->dma_area->status = status; ccw->cmd_code = CCW_CMD_WRITE_STATUS;