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authorStefano Stabellini <stefano.stabellini@xilinx.com>2021-03-19 23:01:40 +0300
committerJuergen Gross <jgross@suse.com>2021-04-23 12:33:50 +0300
commitf5079a9a2a31607a2343e544e9182ce35b030578 (patch)
tree845187f971beecc8c97874a6789a4661e3951056
parenta929e124060c448b367f56b28a0c118876147b1f (diff)
downloadlinux-f5079a9a2a31607a2343e544e9182ce35b030578.tar.xz
xen/arm: introduce XENFEAT_direct_mapped and XENFEAT_not_direct_mapped
Newer Xen versions expose two Xen feature flags to tell us if the domain is directly mapped or not. Only when a domain is directly mapped it makes sense to enable swiotlb-xen on ARM. Introduce a function on ARM to check the new Xen feature flags and also to deal with the legacy case. Call the function xen_swiotlb_detect. Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20210319200140.12512-1-sstabellini@kernel.org Signed-off-by: Juergen Gross <jgross@suse.com>
-rw-r--r--arch/arm/include/asm/xen/swiotlb-xen.h1
-rw-r--r--arch/arm/xen/mm.c14
-rw-r--r--arch/arm64/include/asm/xen/swiotlb-xen.h1
-rw-r--r--arch/arm64/mm/dma-mapping.c2
-rw-r--r--include/xen/arm/swiotlb-xen.h7
-rw-r--r--include/xen/interface/features.h14
-rw-r--r--include/xen/swiotlb-xen.h1
7 files changed, 38 insertions, 2 deletions
diff --git a/arch/arm/include/asm/xen/swiotlb-xen.h b/arch/arm/include/asm/xen/swiotlb-xen.h
new file mode 100644
index 000000000000..455ade5d5320
--- /dev/null
+++ b/arch/arm/include/asm/xen/swiotlb-xen.h
@@ -0,0 +1 @@
+#include <xen/arm/swiotlb-xen.h>
diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 467fa225c3d0..e1b12b242a32 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -135,10 +135,22 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
return;
}
+int xen_swiotlb_detect(void)
+{
+ if (!xen_domain())
+ return 0;
+ if (xen_feature(XENFEAT_direct_mapped))
+ return 1;
+ /* legacy case */
+ if (!xen_feature(XENFEAT_not_direct_mapped) && xen_initial_domain())
+ return 1;
+ return 0;
+}
+
static int __init xen_mm_init(void)
{
struct gnttab_cache_flush cflush;
- if (!xen_initial_domain())
+ if (!xen_swiotlb_detect())
return 0;
xen_swiotlb_init(1, false);
diff --git a/arch/arm64/include/asm/xen/swiotlb-xen.h b/arch/arm64/include/asm/xen/swiotlb-xen.h
new file mode 100644
index 000000000000..455ade5d5320
--- /dev/null
+++ b/arch/arm64/include/asm/xen/swiotlb-xen.h
@@ -0,0 +1 @@
+#include <xen/arm/swiotlb-xen.h>
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 93e87b287556..4bf1dd3eb041 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -53,7 +53,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
iommu_setup_dma_ops(dev, dma_base, size);
#ifdef CONFIG_XEN
- if (xen_initial_domain())
+ if (xen_swiotlb_detect())
dev->dma_ops = &xen_swiotlb_dma_ops;
#endif
}
diff --git a/include/xen/arm/swiotlb-xen.h b/include/xen/arm/swiotlb-xen.h
new file mode 100644
index 000000000000..2994fe6031a0
--- /dev/null
+++ b/include/xen/arm/swiotlb-xen.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARM_SWIOTLB_XEN_H
+#define _ASM_ARM_SWIOTLB_XEN_H
+
+extern int xen_swiotlb_detect(void);
+
+#endif /* _ASM_ARM_SWIOTLB_XEN_H */
diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h
index 6d1384abfbdf..5a7bdefa06a8 100644
--- a/include/xen/interface/features.h
+++ b/include/xen/interface/features.h
@@ -83,6 +83,20 @@
*/
#define XENFEAT_linux_rsdp_unrestricted 15
+/*
+ * A direct-mapped (or 1:1 mapped) domain is a domain for which its
+ * local pages have gfn == mfn. If a domain is direct-mapped,
+ * XENFEAT_direct_mapped is set; otherwise XENFEAT_not_direct_mapped
+ * is set.
+ *
+ * If neither flag is set (e.g. older Xen releases) the assumptions are:
+ * - not auto_translated domains (x86 only) are always direct-mapped
+ * - on x86, auto_translated domains are not direct-mapped
+ * - on ARM, Dom0 is direct-mapped, DomUs are not
+ */
+#define XENFEAT_not_direct_mapped 16
+#define XENFEAT_direct_mapped 17
+
#define XENFEAT_NR_SUBMAPS 1
#endif /* __XEN_PUBLIC_FEATURES_H__ */
diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
index d5eaf9d682b8..dbc4a4b785f6 100644
--- a/include/xen/swiotlb-xen.h
+++ b/include/xen/swiotlb-xen.h
@@ -3,6 +3,7 @@
#define __LINUX_SWIOTLB_XEN_H
#include <linux/swiotlb.h>
+#include <asm/xen/swiotlb-xen.h>
void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir);