kernel/git/stable/linux.git/drivers/xen/privcmd.c, branch linux-6.2.y

xen/privcmd: Fix a possible warning in privcmd_ioctl_mmap_resource()

2022-12-05T12:54:29+00:00

As 'kdata.num' is user-controlled data, if user tries to allocate memory larger than(>=) MAX_ORDER, then kcalloc() will fail, it creates a stack trace and messes up dmesg with a warning. Call trace: -> privcmd_ioctl --> privcmd_ioctl_mmap_resource Add __GFP_NOWARN in order to avoid too large allocation warning. This is detected by static analysis using smatch. Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE") Signed-off-by: Harshit Mogalapalli Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20221126050745.778967-1-harshit.m.mogalapalli@oracle.com Signed-off-by: Juergen Gross

xen: use vma_lookup() in privcmd_ioctl_mmap()

2022-09-27T02:46:16+00:00

vma_lookup() walks the VMA tree for a specific value, find_vma() will search the tree after walking to a specific value. It is more efficient to only walk to the requested value since privcmd_ioctl_mmap() will exit the loop if vm_start != msg->va. Link: https://lkml.kernel.org/r/20220906194824.2110408-20-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Acked-by: Vlastimil Babka Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Will Deacon Signed-off-by: Andrew Morton

xen/privcmd: fix error exit of privcmd_ioctl_dm_op()

2022-08-25T14:40:28+00:00

The error exit of privcmd_ioctl_dm_op() is calling unlock_pages() potentially with pages being NULL, leading to a NULL dereference. Additionally lock_pages() doesn't check for pin_user_pages_fast() having been completely successful, resulting in potentially not locking all pages into memory. This could result in sporadic failures when using the related memory in user mode. Fix all of that by calling unlock_pages() always with the real number of pinned pages, which will be zero in case pages being NULL, and by checking the number of pages pinned by pin_user_pages_fast() matching the expected number of pages. Cc: Fixes: ab520be8cd5d ("xen/privcmd: Add IOCTL_PRIVCMD_DM_OP") Reported-by: Rustam Subkhankulov Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Reviewed-by: Oleksandr Tyshchenko Link: https://lore.kernel.org/r/20220825141918.3581-1-jgross@suse.com Signed-off-by: Juergen Gross

xen/privcmd: drop "pages" parameter from xen_remap_pfn()

2021-10-05T06:20:27+00:00

The function doesn't use it and all of its callers say in a comment that their respective arguments are to be non-NULL only in auto-translated mode. Since xen_remap_domain_mfn_array() isn't supposed to be used by non-PV, drop the parameter there as well. It was bogusly passed as non- NULL (PRIV_VMA_LOCKED) by its only caller anyway. For xen_remap_domain_gfn_range(), otoh, it's not clear at all why this wouldn't want / might not need to gain auto-translated support down the road, so the parameter is retained there despite now remaining unused (and the only caller passing NULL); correct a respective comment as well. Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/036ad8a2-46f9-ac3d-6219-bdc93ab9e10b@suse.com Signed-off-by: Juergen Gross

xen/privcmd: fix error handling in mmap-resource processing

2021-10-05T06:20:22+00:00

xen_pfn_t is the same size as int only on 32-bit builds (and not even on Arm32). Hence pfns[] can't be used directly to read individual error values returned from xen_remap_domain_mfn_array(); every other error indicator would be skipped/ignored on 64-bit. Fixes: 3ad0876554ca ("xen/privcmd: add IOCTL_PRIVCMD_MMAP_RESOURCE") Cc: stable@vger.kernel.org Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/aa6d6a67-6889-338a-a910-51e889f792d5@suse.com Signed-off-by: Juergen Gross

xen/privcmd: replace kcalloc() by kvcalloc() when allocating empty pages

2021-10-05T06:20:17+00:00

Osstest has been suffering test failures for a little while from order-4 allocation failures, resulting from alloc_empty_pages() calling kcalloc(). As there's no need for physically contiguous space here, switch to kvcalloc(). Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/6d698901-98a4-05be-c421-bcd0713f5335@suse.com Signed-off-by: Juergen Gross

xen/privcmd: allow fetching resource sizes

2021-01-13T11:31:17+00:00

Allow issuing an IOCTL_PRIVCMD_MMAP_RESOURCE ioctl with num = 0 and addr = 0 in order to fetch the size of a specific resource. Add a shortcut to the default map resource path, since fetching the size requires no address to be passed in, and thus no VMA to setup. This is missing from the initial implementation, and causes issues when mapping resources that don't have fixed or known sizes. Signed-off-by: Roger Pau Monné Reviewed-by: Juergen Gross Tested-by: Andrew Cooper Cc: stable@vger.kernel.org # >= 4.18 Link: https://lore.kernel.org/r/20210112115358.23346-1-roger.pau@citrix.com Signed-off-by: Juergen Gross

Merge tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2020-09-06T16:59:27+00:00

Pull xen updates from Juergen Gross: "A small series for fixing a problem with Xen PVH guests when running as backends (e.g. as dom0). Mapping other guests' memory is now working via ZONE_DEVICE, thus not requiring to abuse the memory hotplug functionality for that purpose" * tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: add helpers to allocate unpopulated memory memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC xen/balloon: add header guard

xen: add helpers to allocate unpopulated memory

2020-09-04T08:00:01+00:00

To be used in order to create foreign mappings. This is based on the ZONE_DEVICE facility which is used by persistent memory devices in order to create struct pages and kernel virtual mappings for the IOMEM areas of such devices. Note that on kernels without support for ZONE_DEVICE Xen will fallback to use ballooned pages in order to create foreign mappings. The newly added helpers use the same parameters as the existing {alloc/free}_xenballooned_pages functions, which allows for in-place replacement of the callers. Once a memory region has been added to be used as scratch mapping space it will no longer be released, and pages returned are kept in a linked list. This allows to have a buffer of pages and prevents resorting to frequent additions and removals of regions. If enabled (because ZONE_DEVICE is supported) the usage of the new functionality untangles Xen balloon and RAM hotplug from the usage of unpopulated physical memory ranges to map foreign pages, which is the correct thing to do in order to avoid mappings of foreign pages depend on memory hotplug. Note the driver is currently not enabled on Arm platforms because it would interfere with the identity mapping required on some platforms. Signed-off-by: Roger Pau Monné Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20200901083326.21264-4-roger.pau@citrix.com Signed-off-by: Juergen Gross

Merge branch 'akpm' (patches from Andrew)

2020-08-07T18:39:33+00:00

Merge misc updates from Andrew Morton: - a few MM hotfixes - kthread, tools, scripts, ntfs and ocfs2 - some of MM Subsystems affected by this patch series: kthread, tools, scripts, ntfs, ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore, sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan). * emailed patches from Andrew Morton : (162 commits) mm: vmscan: consistent update to pgrefill mm/vmscan.c: fix typo khugepaged: khugepaged_test_exit() check mmget_still_valid() khugepaged: retract_page_tables() remember to test exit khugepaged: collapse_pte_mapped_thp() protect the pmd lock khugepaged: collapse_pte_mapped_thp() flush the right range mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible mm: thp: replace HTTP links with HTTPS ones mm/page_alloc: fix memalloc_nocma_{save/restore} APIs mm/page_alloc.c: skip setting nodemask when we are in interrupt mm/page_alloc: fallbacks at most has 3 elements mm/page_alloc: silence a KASAN false positive mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask() mm/page_alloc.c: simplify pageblock bitmap access mm/page_alloc.c: extract the common part in pfn_to_bitidx() mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits mm/shuffle: remove dynamic reconfiguration mm/memory_hotplug: document why shuffle_zone() is relevant mm/page_alloc: remove nr_free_pagecache_pages() mm: remove vm_total_pages ...