From 50f6393f9654c561df4cdcf8e6cfba7260143601 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 14 Jun 2019 07:46:02 +0200 Subject: xen/swiotlb: fix condition for calling xen_destroy_contiguous_region() The condition in xen_swiotlb_free_coherent() for deciding whether to call xen_destroy_contiguous_region() is wrong: in case the region to be freed is not contiguous calling xen_destroy_contiguous_region() is the wrong thing to do: it would result in inconsistent mappings of multiple PFNs to the same MFN. This will lead to various strange crashes or data corruption. Instead of calling xen_destroy_contiguous_region() in that case a warning should be issued as that situation should never occur. Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Reviewed-by: Jan Beulich Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Juergen Gross --- drivers/xen/swiotlb-xen.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/xen/swiotlb-xen.c') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index d53f3493a6b9..50fd7de54969 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -361,8 +361,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, /* Convert the size to actually allocated. */ size = 1UL << (order + XEN_PAGE_SHIFT); - if (((dev_addr + size - 1 <= dma_mask)) || - range_straddles_page_boundary(phys, size)) + if (!WARN_ON((dev_addr + size - 1 > dma_mask) || + range_straddles_page_boundary(phys, size))) xen_destroy_contiguous_region(phys, order); xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs); -- cgit v1.2.3 From bf70726668c6116aa4976e0cc87f470be6268a2f Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 14 Jun 2019 07:46:03 +0200 Subject: xen/swiotlb: simplify range_straddles_page_boundary() range_straddles_page_boundary() is open coding several macros from include/xen/page.h. Use those instead. Additionally there is no need to have check_pages_physically_contiguous() as a separate function as it is used only once, so merge it into range_straddles_page_boundary(). Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Juergen Gross --- drivers/xen/swiotlb-xen.c | 28 ++++++---------------------- 1 file changed, 6 insertions(+), 22 deletions(-) (limited to 'drivers/xen/swiotlb-xen.c') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 50fd7de54969..37ddcfcfbb21 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -83,34 +83,18 @@ static inline dma_addr_t xen_virt_to_bus(void *address) return xen_phys_to_bus(virt_to_phys(address)); } -static int check_pages_physically_contiguous(unsigned long xen_pfn, - unsigned int offset, - size_t length) +static inline int range_straddles_page_boundary(phys_addr_t p, size_t size) { - unsigned long next_bfn; - int i; - int nr_pages; + unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p); + unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size); next_bfn = pfn_to_bfn(xen_pfn); - nr_pages = (offset + length + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT; - for (i = 1; i < nr_pages; i++) { + for (i = 1; i < nr_pages; i++) if (pfn_to_bfn(++xen_pfn) != ++next_bfn) - return 0; - } - return 1; -} + return 1; -static inline int range_straddles_page_boundary(phys_addr_t p, size_t size) -{ - unsigned long xen_pfn = XEN_PFN_DOWN(p); - unsigned int offset = p & ~XEN_PAGE_MASK; - - if (offset + size <= XEN_PAGE_SIZE) - return 0; - if (check_pages_physically_contiguous(xen_pfn, offset, size)) - return 0; - return 1; + return 0; } static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) -- cgit v1.2.3 From b877ac9815a8fe7e5f6d7fdde3dc34652408840a Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 14 Jun 2019 07:46:04 +0200 Subject: xen/swiotlb: remember having called xen_create_contiguous_region() Instead of always calling xen_destroy_contiguous_region() in case the memory is DMA-able for the used device, do so only in case it has been made DMA-able via xen_create_contiguous_region() before. This will avoid a lot of xen_destroy_contiguous_region() calls for 64-bit capable devices. As the memory in question is owned by swiotlb-xen the PG_owner_priv_1 flag of the first allocated page can be used for remembering. Signed-off-by: Juergen Gross Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Juergen Gross --- drivers/xen/swiotlb-xen.c | 4 +++- include/linux/page-flags.h | 4 ++++ 2 files changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/xen/swiotlb-xen.c') diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 37ddcfcfbb21..ceb681cf64bb 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -322,6 +322,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size, xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs); return NULL; } + SetPageXenRemapped(virt_to_page(ret)); } memset(ret, 0, size); return ret; @@ -346,7 +347,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, size = 1UL << (order + XEN_PAGE_SHIFT); if (!WARN_ON((dev_addr + size - 1 > dma_mask) || - range_straddles_page_boundary(phys, size))) + range_straddles_page_boundary(phys, size)) && + TestClearPageXenRemapped(virt_to_page(vaddr))) xen_destroy_contiguous_region(phys, order); xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs); diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index b848517da64c..f91cb8898ff0 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -152,6 +152,8 @@ enum pageflags { PG_savepinned = PG_dirty, /* Has a grant mapping of another (foreign) domain's page. */ PG_foreign = PG_owner_priv_1, + /* Remapped by swiotlb-xen. */ + PG_xen_remapped = PG_owner_priv_1, /* SLOB */ PG_slob_free = PG_private, @@ -329,6 +331,8 @@ PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND); PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND); +PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) + TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND) PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) -- cgit v1.2.3