Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature

Pierre Morel
2020-06-17T12:00:10Z

On 2020-06-17 13:22, Heiko Carstens wrote:
> On Wed, Jun 17, 2020 at 12:43:57PM +0200, 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@linux.ibm.com>
>> Acked-by: Jason Wang <jasowang@redhat.com>
>> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>> 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