[PATCH V4 8/8] arm/xen: Assign xen-grant DMA ops for xen-grant DMA devices

Oleksandr Tyshchenko
2022-06-02T19:24:59Z

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

By assigning xen-grant DMA ops we will restrict memory access for
passed device using Xen grant mappings. This is needed for using any
virtualized device (e.g. virtio) in Xen guests in a safe manner.

Please note, for the virtio devices the XEN_VIRTIO config should
be enabled (it forces ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS).

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes RFC -> V1:
- update commit subject/description
- remove #ifdef CONFIG_XEN_VIRTIO
- re-organize the check taking into the account that
swiotlb and virtio cases are mutually exclusive
- update according to the new naming scheme:
s/virtio/grant_dma

Changes V1 -> V2:
- add Stefano's R-b
- remove arch_has_restricted_virtio_memory_access() check
- update commit description
- remove the inclusion of virtio_config.h

Changes V2 -> V3:
- no changes

Changes V3 -> V4:
- no changes
---
include/xen/arm/xen-ops.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/xen/arm/xen-ops.h b/include/xen/arm/xen-ops.h
index 288deb1..b0766a6 100644
--- a/include/xen/arm/xen-ops.h
+++ b/include/xen/arm/xen-ops.h
@@ -3,11 +3,14 @@
#define _ASM_ARM_XEN_OPS_H

#include <xen/swiotlb-xen.h>
+#include <xen/xen-ops.h>

static inline void xen_setup_dma_ops(struct device *dev)
{
#ifdef CONFIG_XEN
- if (xen_swiotlb_detect())
+ if (xen_is_grant_dma_device(dev))
+ xen_grant_setup_dma_ops(dev);
+ else if (xen_swiotlb_detect())
dev->dma_ops = &xen_swiotlb_dma_ops;
#endif
}
--
2.7.4