On 2020-06-17 15:36, Tom Lendacky wrote:
On 6/17/20 5:43 AM, Pierre Morel wrote:
An architecture protecting the guest memory against unauthorized host
access may want to enforce VIRTIO I/O device protection through the
use of VIRTIO_F_IOMMU_PLATFORM.
Let's give a chance to the architecture to accept or not devices
without VIRTIO_F_IOMMU_PLATFORM.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/mm/init.c | 6 ++++++
drivers/virtio/virtio.c | 22 ++++++++++++++++++++++
include/linux/virtio.h | 2 ++
3 files changed, 30 insertions(+)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6dc7c3b60ef6..215070c03226 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -45,6 +45,7 @@
#include <asm/kasan.h>
#include <asm/dma-mapping.h>
#include <asm/uv.h>
+#include <linux/virtio.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
@@ -161,6 +162,11 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
+int arch_needs_virtio_iommu_platform(struct virtio_device *dev)
+{
+ return is_prot_virt_guest();
+}
+
/* protected virtualization */
static void pv_init(void)
{
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index a977e32a88f2..aa8e01104f86 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -167,6 +167,21 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status)
}
EXPORT_SYMBOL_GPL(virtio_add_status);
+/*
+ * arch_needs_virtio_iommu_platform - provide arch specific hook when finalizing
+ * features for VIRTIO device dev
+ * @dev: the VIRTIO device being added
+ *
+ * Permits the platform to provide architecture specific functionality when
+ * devices features are finalized. This is the default implementation.
+ * Architecture implementations can override this.
+ */
+
+int __weak arch_needs_virtio_iommu_platform(struct virtio_device *dev)
+{
+ return 0;
+}
+
int virtio_finalize_features(struct virtio_device *dev)
{
int ret = dev->config->finalize_features(dev);
@@ -179,6 +194,13 @@ int virtio_finalize_features(struct virtio_device *dev)
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
+ if (arch_needs_virtio_iommu_platform(dev) &&
+ !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
Just a style nit, but the "!virtio..." should be directly under the
"arch_...", not tabbed out.
Oh right, thanks!
Pierre
Thanks,
Tom
...snip...
--
Pierre Morel
IBM Lab Boeblingen
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