On 2020-07-09 10:57, Cornelia Huck wrote:
On Thu, 9 Jul 2020 10:39:19 +0200
Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
If protected virtualization is active on s390, the virtio queues are
not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been
negotiated. Use the new arch_validate_virtio_features() interface to
fail probe if that's not the case, preventing a host error on access
attempt
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
arch/s390/mm/init.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6dc7c3b60ef6..b8e6f90117da 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_config.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
@@ -161,6 +162,32 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
+/*
+ * arch_validate_virtio_features
+ * @dev: the VIRTIO device being added
+ *
+ * Return an error if required features are missing on a guest running
+ * with protected virtualization.
+ */
+int arch_validate_virtio_features(struct virtio_device *dev)
+{
+ if (!is_prot_virt_guest())
+ return 0;
+
+ if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
+ dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n");
I'd probably use "legacy virtio not supported with protected
virtualization".
+ return -ENODEV;
+ }
+
+ if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
+ dev_warn(&dev->dev,
+ "device must provide VIRTIO_F_IOMMU_PLATFORM\n");
"support for limited memory access required for protected
virtualization"
?
Mentioning the feature flag is shorter in both cases, though.
And I think easier to look for in case of debugging purpose.
I change it if there is more demands.
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
/* protected virtualization */
static void pv_init(void)
{
Either way,
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Thanks,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
