Re: [PATCH v12 2/2] s390: virtio: PV needs VIRTIO I/O device protection

Christian Borntraeger
2020-09-10T09:10:09Z

On 10.09.20 10:53, Pierre Morel wrote:
> If protected virtualization is active on s390, VIRTIO has only retricted
> access to the guest memory.
> Define CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS and export
> arch_has_restricted_virtio_memory_access to advertize VIRTIO if that's
> the case.
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

Michael, I am fine if this patch goes via the virtio tree.

> ---
> arch/s390/Kconfig | 1 +
> arch/s390/mm/init.c | 11 +++++++++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index b29fcc66ec39..938246200d39 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -820,6 +820,7 @@ menu "Virtualization"
> config PROTECTED_VIRTUALIZATION_GUEST
> def_bool n
> prompt "Protected virtualization guest support"
> + select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
> help
> Select this option, if you want to be able to run this
> kernel as a protected virtualization KVM guest.
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index 0d282081dc1f..e27f050cb516 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);
>
> @@ -160,6 +161,16 @@ bool force_dma_unencrypted(struct device *dev)
> return is_prot_virt_guest();
> }
>
> +#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
> +
> +int arch_has_restricted_virtio_memory_access(void)
> +{
> + return is_prot_virt_guest();
> +}
> +EXPORT_SYMBOL(arch_has_restricted_virtio_memory_access);
> +
> +#endif
> +
> /* protected virtualization */
> static void pv_init(void)
> {
>