[PATCH 05/15] arm/xen: don't check for xen_initial_domain() in xen_create_contiguous_region

Christoph Hellwig
2022-03-14T07:32:16Z

From: Stefano Stabellini <sstabellini@kernel.org>

It used to be that Linux enabled swiotlb-xen when running a dom0 on ARM.
Since f5079a9a2a31 "xen/arm: introduce XENFEAT_direct_mapped and
XENFEAT_not_direct_mapped", Linux detects whether to enable or disable
swiotlb-xen based on the new feature flags: XENFEAT_direct_mapped and
XENFEAT_not_direct_mapped.

However, there is still a leftover xen_initial_domain() check in
xen_create_contiguous_region. Remove the check as
xen_create_contiguous_region is only called by swiotlb-xen during
initialization. If xen_create_contiguous_region is called, we know Linux
is running 1:1 mapped so there is no need for additional checks.

Also update the in-code comment.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/arm/xen/mm.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index a7e54a087b802..28c2070602535 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -122,10 +122,7 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
unsigned int address_bits,
dma_addr_t *dma_handle)
{
- if (!xen_initial_domain())
- return -EINVAL;
-
- /* we assume that dom0 is mapped 1:1 for now */
+ /* the domain is 1:1 mapped to use swiotlb-xen */
*dma_handle = pstart;
return 0;
}
--
2.30.2