From: Christoph Hellwig <hch@lst.de>
To: Stefano Stabellini <sstabellini@kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
gross@suse.com, boris.ostrovsky@oracle.com
Cc: xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 08/11] swiotlb-xen: use the same foreign page check everywhere
Date: Thu, 5 Sep 2019 13:34:05 +0200 [thread overview]
Message-ID: <20190905113408.3104-9-hch@lst.de> (raw)
In-Reply-To: <20190905113408.3104-1-hch@lst.de>
xen_dma_map_page uses a different and more complicated check for foreign
pages than the other three cache maintainance helpers. Switch it to the
simpler pfn_valid method a well, and document the scheme with a single
improved comment in xen_dma_map_page.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
include/xen/arm/page-coherent.h | 31 +++++++++----------------------
1 file changed, 9 insertions(+), 22 deletions(-)
diff --git a/include/xen/arm/page-coherent.h b/include/xen/arm/page-coherent.h
index a840d6949a87..a8d9c0678c27 100644
--- a/include/xen/arm/page-coherent.h
+++ b/include/xen/arm/page-coherent.h
@@ -53,23 +53,17 @@ static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
dma_addr_t dev_addr, unsigned long offset, size_t size,
enum dma_data_direction dir, unsigned long attrs)
{
- unsigned long page_pfn = page_to_xen_pfn(page);
- unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
- unsigned long compound_pages =
- (1<<compound_order(page)) * XEN_PFN_PER_PAGE;
- bool local = (page_pfn <= dev_pfn) &&
- (dev_pfn - page_pfn < compound_pages);
+ unsigned long pfn = PFN_DOWN(dev_addr);
/*
- * Dom0 is mapped 1:1, while the Linux page can span across
- * multiple Xen pages, it's not possible for it to contain a
- * mix of local and foreign Xen pages. So if the first xen_pfn
- * == mfn the page is local otherwise it's a foreign page
- * grant-mapped in dom0. If the page is local we can safely
- * call the native dma_ops function, otherwise we call the xen
- * specific function.
+ * Dom0 is mapped 1:1, and while the Linux page can span across multiple
+ * Xen pages, it is not possible for it to contain a mix of local and
+ * foreign Xen pages. Calling pfn_valid on a foreign mfn will always
+ * return false, so if pfn_valid returns true the pages is local and we
+ * can use the native dma-direct functions, otherwise we call the Xen
+ * specific version.
*/
- if (local)
+ if (pfn_valid(pfn))
dma_direct_map_page(hwdev, page, offset, size, dir, attrs);
else
__xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);
@@ -79,14 +73,7 @@ static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
unsigned long pfn = PFN_DOWN(handle);
- /*
- * Dom0 is mapped 1:1, while the Linux page can be spanned accross
- * multiple Xen page, it's not possible to have a mix of local and
- * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
- * foreign mfn will always return false. If the page is local we can
- * safely call the native dma_ops function, otherwise we call the xen
- * specific function.
- */
+
if (pfn_valid(pfn))
dma_direct_unmap_page(hwdev, handle, size, dir, attrs);
else
--
2.20.1
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next prev parent reply other threads:[~2019-09-05 11:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 11:33 swiotlb-xen cleanups v4 Christoph Hellwig
2019-09-05 11:33 ` [PATCH 01/11] xen/arm: use dma-noncoherent.h calls for xen-swiotlb cache maintainance Christoph Hellwig
2019-09-10 0:18 ` Stefano Stabellini
2019-09-05 11:33 ` [PATCH 02/11] xen/arm: consolidate page-coherent.h Christoph Hellwig
2019-09-10 0:18 ` Stefano Stabellini
2019-09-05 11:34 ` [PATCH 03/11] xen/arm: use dev_is_dma_coherent Christoph Hellwig
2019-09-05 11:34 ` [PATCH 04/11] xen/arm: simplify dma_cache_maint Christoph Hellwig
2019-09-05 11:34 ` [PATCH 05/11] xen/arm: remove xen_dma_ops Christoph Hellwig
2019-09-05 11:34 ` [PATCH 06/11] xen: remove the exports for xen_{create, destroy}_contiguous_region Christoph Hellwig
2019-09-05 11:34 ` [PATCH 07/11] swiotlb-xen: remove xen_swiotlb_dma_mmap and xen_swiotlb_dma_get_sgtable Christoph Hellwig
2019-09-05 11:34 ` Christoph Hellwig [this message]
2019-09-05 11:34 ` [PATCH 09/11] swiotlb-xen: simplify cache maintainance Christoph Hellwig
2019-09-06 13:52 ` Boris Ostrovsky
2019-09-06 14:01 ` Christoph Hellwig
2019-09-06 14:07 ` [Xen-devel] " Andrew Cooper
2019-09-06 14:19 ` Boris Ostrovsky
2019-09-06 14:43 ` Konrad Rzeszutek Wilk
2019-09-06 14:46 ` Boris Ostrovsky
2019-09-05 11:34 ` [PATCH 10/11] swiotlb-xen: merge xen_unmap_single into xen_swiotlb_unmap_page Christoph Hellwig
2019-09-05 11:34 ` [PATCH 11/11] arm64: use asm-generic/dma-mapping.h Christoph Hellwig
2019-09-11 10:45 ` swiotlb-xen cleanups v4 Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2019-08-16 13:00 swiotlb-xen cleanups Christoph Hellwig
2019-08-16 13:00 ` [PATCH 08/11] swiotlb-xen: use the same foreign page check everywhere Christoph Hellwig
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