On 2020-06-16 08:55, Christian Borntraeger wrote:
On 15.06.20 14:39, 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: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Thanks,
Shouldnt we maybe add a pr_warn if that happens to help the admins to understand what is going on?
Yes, Connie asked for it too, good that you remind it to me, I add it.
Thanks,
Pierre
---
arch/s390/mm/init.c | 6 ++++++
drivers/virtio/virtio.c | 9 +++++++++
include/linux/virtio.h | 2 ++
3 files changed, 17 insertions(+)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 87b2d024e75a..3f04ad09650f 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -46,6 +46,7 @@
#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);
@@ -162,6 +163,11 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
+int arch_needs_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..30091089bee8 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -167,6 +167,11 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status)
}
EXPORT_SYMBOL_GPL(virtio_add_status);
+int __weak arch_needs_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 +184,10 @@ int virtio_finalize_features(struct virtio_device *dev)
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
+ if (arch_needs_iommu_platform(dev) &&
+ !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM))
+ return -EIO;
+
virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
status = dev->config->get_status(dev);
if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index a493eac08393..2c46b310c38c 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -195,4 +195,6 @@ void unregister_virtio_driver(struct virtio_driver *drv);
#define module_virtio_driver(__virtio_driver) \
module_driver(__virtio_driver, register_virtio_driver, \
unregister_virtio_driver)
+
+int arch_needs_iommu_platform(struct virtio_device *dev);
#endif /* _LINUX_VIRTIO_H */
--
Pierre Morel
IBM Lab Boeblingen
