| Message ID | 20210319200140.12512-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f5079a9a2a31607a2343e544e9182ce35b030578 |
| Headers | show |
| Series | [v3] xen/arm: introduce XENFEAT_direct_mapped and XENFEAT_not_direct_mapped | expand |
On 3/19/21 4:01 PM, Stefano Stabellini wrote: > From: Stefano Stabellini <stefano.stabellini@xilinx.com> > > 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>
On 19.03.21 21:01, Stefano Stabellini wrote: > From: Stefano Stabellini <stefano.stabellini@xilinx.com> > > 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> Pushed to xen/tip.git for-linus-5.13 Juergen
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);