On 5/6/20 12:14 PM, Nataliya Korovkina wrote: > On Wed, May 6, 2020 at 9:43 AM Boris Ostrovsky > <boris.ostrov...@oracle.com> wrote: >> >> On 5/6/20 9:08 AM, Nataliya Korovkina wrote: >>> Hello, >>> >>> What I found out: rpi_firmware_property_list() allocates memory from >>> dma_atomic_pool which was mapped to VMALLOC region, so virt_to_page() >>> is not eligible in this case. >> >> So then it seems it didn't go through xen_swiotlb_alloc_coherent(). In >> which case it has no business calling xen_swiotlb_free_coherent(). >> >> >> -boris >> >> >> >> > It does go. > dma_alloc_coherent() indirectly calls xen_swiotlb_alloc_coherent(), > then xen_alloc_coherent_pages() eventually calls arch_dma_alloc() in > remap.c which successfully allocates pages from atomic pool.
Yes, I was looking at x86's implementation of xen_alloc_coherent_pages(). > > The patch Julien offered for domian_build.c moved Dom0 banks in the > first G of RAM. > So it covered the previous symptom (a crash during allocation) because > now we avoid pathway when we mark a page "XenMapped". > > But the symptom still remains in xen_swiotlb_free_coherent() because > "TestPage..." is called unconditionally. virt_to_page() is not > applicable to such allocations. Perhaps we just need to make sure we are using right virt-to-page method. Something like diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index b6d2776..f224e69 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -335,6 +335,7 @@ int __ref xen_swiotlb_init(int verbose, bool early) int order = get_order(size); phys_addr_t phys; u64 dma_mask = DMA_BIT_MASK(32); + struct page *pg; if (hwdev && hwdev->coherent_dma_mask) dma_mask = hwdev->coherent_dma_mask; @@ -346,9 +347,12 @@ int __ref xen_swiotlb_init(int verbose, bool early) /* Convert the size to actually allocated. */ size = 1UL << (order + XEN_PAGE_SHIFT); + pg = is_vmalloc_addr(vaddr) ? vmalloc_to_page(vaddr) : virt_to_page(vaddr); + BUG_ON(!pg); + if (!WARN_ON((dev_addr + size - 1 > dma_mask) || range_straddles_page_boundary(phys, size)) && - TestClearPageXenRemapped(virt_to_page(vaddr))) + TestClearPageXenRemapped(pg)) xen_destroy_contiguous_region(phys, order); xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs); (I have not tested this at all)
