arm/xen: don't check for xen_initial_domain() in xen_create_contiguous_region

sstabellini · Christoph Hellwig · commit 9bbe7a7fc126 · 2022-04-18T07:21:09.000+02:00
It used to be that Linux enabled swiotlb-xen when running a dom0 on ARM. Since f5079a9 "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> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git 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;
 }

Original file line number	Diff line number	Diff line change
`@@ -122,10 +122,7 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,`
`122`	`122`	`unsigned int address_bits,`
`123`	`123`	`dma_addr_t *dma_handle)`
`124`	`124`	`{`
`125`		`- if (!xen_initial_domain())`
`126`		`- return -EINVAL;`
`127`		`-`
`128`		`- /* we assume that dom0 is mapped 1:1 for now */`
	`125`	`+ /* the domain is 1:1 mapped to use swiotlb-xen */`
`129`	`126`	`*dma_handle = pstart;`
`130`	`127`	`return 0;`
`131`	`128`	`}`