kernel.git/arch/arm/xen, branch linux-5.18.y

xen/arm: Fix race in RB-tree based P2M accounting

2022-07-07T15:55:01Z

commit b75cd218274e01d026dc5240e86fdeb44bbed0c8 upstream. During the PV driver life cycle the mappings are added to the RB-tree by set_foreign_p2m_mapping(), which is called from gnttab_map_refs() and are removed by clear_foreign_p2m_mapping() which is called from gnttab_unmap_refs(). As both functions end up calling __set_phys_to_machine_multi() which updates the RB-tree, this function can be called concurrently. There is already a "p2m_lock" to protect against concurrent accesses, but the problem is that the first read of "phys_to_mach.rb_node" in __set_phys_to_machine_multi() is not covered by it, so this might lead to the incorrect mappings update (removing in our case) in RB-tree. In my environment the related issue happens rarely and only when PV net backend is running, the xen_add_phys_to_mach_entry() claims that it cannot add new pfn <-> mfn mapping to the tree since it is already exists which results in a failure when mapping foreign pages. But there might be other bad consequences related to the non-protected root reads such use-after-free, etc. While at it, also fix the similar usage in __pfn_to_mfn(), so initialize "struct rb_node *n" with the "p2m_lock" held in both functions to avoid possible bad consequences. This is CVE-2022-33744 / XSA-406. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

arm/xen: Fix some refcount leaks

2022-04-22T20:33:33Z

The of_find_compatible_node() function returns a node pointer with refcount incremented, We should use of_node_put() on it when done Add the missing of_node_put() to release the refcount. Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()") Fixes: b2371587fe0c ("arm/xen: Read extended regions from DT and init Xen resource") Signed-off-by: Miaoqian Lin Reviewed-by: Stefano Stabellini Signed-off-by: Stefano Stabellini

arm/xen: Read extended regions from DT and init Xen resource

2022-01-06T08:53:41Z

This patch implements arch_xen_unpopulated_init() on Arm where the extended regions (if any) are gathered from DT and inserted into specific Xen resource to be used as unused address space for Xen scratch pages by unpopulated-alloc code. The extended region (safe range) is a region of guest physical address space which is unused and could be safely used to create grant/foreign mappings instead of wasting real RAM pages from the domain memory for establishing these mappings. The extended regions are chosen by the hypervisor at the domain creation time and advertised to it via "reg" property under hypervisor node in the guest device-tree. As region 0 is reserved for grant table space (always present), the indexes for extended regions are 1...N. If arch_xen_unpopulated_init() fails for some reason the default behaviour will be restored (allocate xenballooned pages). This patch also removes XEN_UNPOPULATED_ALLOC dependency on x86. Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/1639080336-26573-6-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross

arm/xen: Switch to use gnttab_setup_auto_xlat_frames() for DT

2022-01-06T08:53:31Z

Read the start address of the grant table space from DT (region 0). This patch mostly restores behaviour before commit 3cf4095d7446 ("arm/xen: Use xen_xlate_map_ballooned_pages to setup grant table") but trying not to break the ACPI support added after that commit. So the patch touches DT part only and leaves the ACPI part with xen_xlate_map_ballooned_pages(). Also in order to make a code more resilient use a fallback to xen_xlate_map_ballooned_pages() if grant table region wasn't found. This is a preparation for using Xen extended region feature where unused regions of guest physical address space (provided by the hypervisor) will be used to create grant/foreign/whatever mappings instead of wasting real RAM pages from the domain memory for establishing these mappings. The immediate benefit of this change: - Avoid superpage shattering in Xen P2M when establishing stage-2 mapping (GFN <-> MFN) for the grant table space - Avoid wasting real RAM pages (reducing the amount of memory usuable) for mapping grant table space - The grant table space is always mapped at the exact same place (region 0 is reserved for the grant table) Signed-off-by: Oleksandr Tyshchenko Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/1639080336-26573-3-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross

xen: allow pv-only hypercalls only with CONFIG_XEN_PV

2021-11-02T13:11:01Z

Put the definitions of the hypercalls usable only by pv guests inside CONFIG_XEN_PV sections. On Arm two dummy functions related to pv hypercalls can be removed. While at it remove the no longer supported tmem hypercall definition. Signed-off-by: Juergen Gross Link: https://lore.kernel.org/r/20211028081221.2475-3-jgross@suse.com Reviewed-by: Boris Ostrovsky Signed-off-by: Boris Ostrovsky

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2021-07-06T18:52:58Z

Pull ARM development updates from Russell King: - Make it clear __swp_entry_to_pte() uses PTE_TYPE_FAULT - Updates for setting vmalloc size via command line to resolve an issue with the 8MiB hole not properly being accounted for, and clean up the code. - ftrace support for module PLTs - Spelling fixes - kbuild updates for removing generated files and pattern rules for generating files - Clang/llvm updates - Change the way the kernel is mapped, placing it in vmalloc space instead. - Remove arm_pm_restart from arm and aarch64. * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (29 commits) ARM: 9098/1: ftrace: MODULE_PLT: Fix build problem without DYNAMIC_FTRACE ARM: 9097/1: mmu: Declare section start/end correctly ARM: 9096/1: Remove arm_pm_restart() ARM: 9095/1: ARM64: Remove arm_pm_restart() ARM: 9094/1: Register with kernel restart handler ARM: 9093/1: drivers: firmwapsci: Register with kernel restart handler ARM: 9092/1: xen: Register with kernel restart handler ARM: 9091/1: Revert "mm: qsd8x50: Fix incorrect permission faults" ARM: 9090/1: Map the lowmem and kernel separately ARM: 9089/1: Define kernel physical section start and end ARM: 9088/1: Split KERNEL_OFFSET from PAGE_OFFSET ARM: 9087/1: kprobes: test-thumb: fix for LLVM_IAS=1 ARM: 9086/1: syscalls: use pattern rules to generate syscall headers ARM: 9085/1: remove unneeded abi parameter to syscallnr.sh ARM: 9084/1: simplify the build rule of mach-types.h ARM: 9083/1: uncompress: atags_to_fdt: Spelling s/REturn/Return/ ARM: 9082/1: [v2] mark prepare_page_table as __init ARM: 9079/1: ftrace: Add MODULE_PLTS support ARM: 9078/1: Add warn suppress parameter to arm_gen_branch_link() ARM: 9077/1: PLT: Move struct plt_entries definition to header ...

ARM: 9092/1: xen: Register with kernel restart handler

2021-06-13T17:16:44Z

Register with kernel restart handler instead of setting arm_pm_restart directly. Select a high priority of 192 to ensure that default restart handlers are replaced if Xen is running. Acked-by: Arnd Bergmann Reviewed-by: Wolfram Sang Reviewed-by: Stefano Stabellini Signed-off-by: Guenter Roeck Signed-off-by: Thierry Reding Signed-off-by: Lee Jones Signed-off-by: Russell King

xen/swiotlb: check if the swiotlb has already been initialized

2021-05-14T13:52:11Z

xen_swiotlb_init calls swiotlb_late_init_with_tbl, which fails with -ENOMEM if the swiotlb has already been initialized. Add an explicit check io_tlb_default_mem != NULL at the beginning of xen_swiotlb_init. If the swiotlb is already initialized print a warning and return -EEXIST. On x86, the error propagates. On ARM, we don't actually need a special swiotlb buffer (yet), any buffer would do. So ignore the error and continue. CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Stefano Stabellini Reviewed-by: Boris Ostrovsky Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210512201823.1963-3-sstabellini@kernel.org Signed-off-by: Juergen Gross

xen/arm: move xen_swiotlb_detect to arm/swiotlb-xen.h

2021-05-14T13:52:05Z

Move xen_swiotlb_detect to a static inline function to make it available to !CONFIG_XEN builds. CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Stefano Stabellini Reviewed-by: Christoph Hellwig Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20210512201823.1963-1-sstabellini@kernel.org Signed-off-by: Juergen Gross

Merge branch 'stable/for-linus-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

2021-05-04T17:58:49Z

Pull swiotlb updates from Konrad Rzeszutek Wilk: "Christoph Hellwig has taken a cleaver and trimmed off the not-needed code and nicely folded duplicate code in the generic framework. This lays the groundwork for more work to add extra DMA-backend-ish in the future. Along with that some bug-fixes to make this a nice working package" * 'stable/for-linus-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: swiotlb: don't override user specified size in swiotlb_adjust_size swiotlb: Fix the type of index swiotlb: Make SWIOTLB_NO_FORCE perform no allocation ARM: Qualify enabling of swiotlb_init() swiotlb: remove swiotlb_nr_tbl swiotlb: dynamically allocate io_tlb_default_mem swiotlb: move global variables into a new io_tlb_mem structure xen-swiotlb: remove the unused size argument from xen_swiotlb_fixup xen-swiotlb: split xen_swiotlb_init swiotlb: lift the double initialization protection from xen-swiotlb xen-swiotlb: remove xen_io_tlb_start and xen_io_tlb_nslabs xen-swiotlb: remove xen_set_nslabs xen-swiotlb: use io_tlb_end in xen_swiotlb_dma_supported xen-swiotlb: use is_swiotlb_buffer in is_xen_swiotlb_buffer swiotlb: split swiotlb_tbl_sync_single swiotlb: move orig addr and size validation into swiotlb_bounce swiotlb: remove the alloc_size parameter to swiotlb_tbl_unmap_single powerpc/svm: stop using io_tlb_start