On 2020-06-17 13:22, Heiko Carstens wrote:

On Wed, Jun 17, 2020 at 12:43:57PM +0200, Pierre Morel wrote:

quoted

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 <redacted>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Christian Borntraeger <redacted>
---
  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)

Can we please stop dumping random code to arch/s390/mm/init.c?

All the protected virtualization functions should go into a separate
file (e.g. mem_encrypt.c like on x86), some of which could also be in
header files.

Please consider this a comment for the future.. just go ahead with
this patch as-is.

OK, thanks Heiko,
Pierre

-- 
Pierre Morel
IBM Lab Boeblingen