linux/virt, branch v5.14

KVM: Do not leak memory for duplicate debugfs directories

2021-08-04T10:02:03Z

KVM creates a debugfs directory for each VM in order to store statistics about the virtual machine. The directory name is built from the process pid and a VM fd. While generally unique, it is possible to keep a file descriptor alive in a way that causes duplicate directories, which manifests as these messages: [ 471.846235] debugfs: Directory '20245-4' with parent 'kvm' already present! Even though this should not happen in practice, it is more or less expected in the case of KVM for testcases that call KVM_CREATE_VM and close the resulting file descriptor repeatedly and in parallel. When this happens, debugfs_create_dir() returns an error but kvm_create_vm_debugfs() goes on to allocate stat data structs which are later leaked. The slow memory leak was spotted by syzkaller, where it caused OOM reports. Since the issue only affects debugfs, do a lookup before calling debugfs_create_dir, so that the message is downgraded and rate-limited. While at it, ensure kvm->debugfs_dentry is NULL rather than an error if it is not created. This fixes kvm_destroy_vm_debugfs, which was not checking IS_ERR_OR_NULL correctly. Cc: stable@vger.kernel.org Fixes: 536a6f88c49d ("KVM: Create debugfs dir and stat files for each VM") Reported-by: Alexey Kardashevskiy Suggested-by: Greg Kroah-Hartman Acked-by: Greg Kroah-Hartman Signed-off-by: Paolo Bonzini

KVM: add missing compat KVM_CLEAR_DIRTY_LOG

2021-07-27T20:59:01Z

The arguments to the KVM_CLEAR_DIRTY_LOG ioctl include a pointer, therefore it needs a compat ioctl implementation. Otherwise, 32-bit userspace fails to invoke it on 64-bit kernels; for x86 it might work fine by chance if the padding is zero, but not on big-endian architectures. Reported-by: Thomas Sattler Cc: stable@vger.kernel.org Fixes: 2a31b9db1535 ("kvm: introduce manual dirty log reprotect") Reviewed-by: Peter Xu Signed-off-by: Paolo Bonzini

KVM: use cpu_relax when halt polling

2021-07-27T20:59:01Z

SMT siblings share caches and other hardware, and busy halt polling will degrade its sibling performance if its sibling is working Sean Christopherson suggested as below: "Rather than disallowing halt-polling entirely, on x86 it should be sufficient to simply have the hardware thread yield to its sibling(s) via PAUSE. It probably won't get back all performance, but I would expect it to be close. This compiles on all KVM architectures, and AFAICT the intended usage of cpu_relax() is identical for all architectures." Suggested-by: Sean Christopherson Signed-off-by: Li RongQing Message-Id: <20210727111247.55510-1-lirongqing@baidu.com> Signed-off-by: Paolo Bonzini

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2021-07-15T18:56:07Z

Pull kvm fixes from Paolo Bonzini: - Allow again loading KVM on 32-bit non-PAE builds - Fixes for host SMIs on AMD - Fixes for guest SMIs on AMD - Fixes for selftests on s390 and ARM - Fix memory leak - Enforce no-instrumentation area on vmentry when hardware breakpoints are in use. * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (25 commits) KVM: selftests: smm_test: Test SMM enter from L2 KVM: nSVM: Restore nested control upon leaving SMM KVM: nSVM: Fix L1 state corruption upon return from SMM KVM: nSVM: Introduce svm_copy_vmrun_state() KVM: nSVM: Check that VM_HSAVE_PA MSR was set before VMRUN KVM: nSVM: Check the value written to MSR_VM_HSAVE_PA KVM: SVM: Fix sev_pin_memory() error checks in SEV migration utilities KVM: SVM: Return -EFAULT if copy_to_user() for SEV mig packet header fails KVM: SVM: add module param to control the #SMI interception KVM: SVM: remove INIT intercept handler KVM: SVM: #SMI interception must not skip the instruction KVM: VMX: Remove vmx_msr_index from vmx.h KVM: X86: Disable hardware breakpoints unconditionally before kvm_x86->run() KVM: selftests: Address extra memslot parameters in vm_vaddr_alloc kvm: debugfs: fix memory leak in kvm_create_vm_debugfs KVM: x86/pmu: Clear anythread deprecated bit when 0xa leaf is unsupported on the SVM KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio KVM: SVM: Revert clearing of C-bit on GPA in #NPF handler KVM: x86/mmu: Do not apply HPA (memory encryption) mask to GPAs KVM: x86: Use kernel's x86_phys_bits to handle reduced MAXPHYADDR ...

kvm: debugfs: fix memory leak in kvm_create_vm_debugfs

2021-07-15T14:19:40Z

In commit bc9e9e672df9 ("KVM: debugfs: Reuse binary stats descriptors") loop for filling debugfs_stat_data was copy-pasted 2 times, but in the second loop pointers are saved over pointers allocated in the first loop. All this causes is a memory leak, fix it. Fixes: bc9e9e672df9 ("KVM: debugfs: Reuse binary stats descriptors") Signed-off-by: Pavel Skripkin Reviewed-by: Jing Zhang Message-Id: <20210701195500.27097-1-paskripkin@gmail.com> Reviewed-by: Jing Zhang Signed-off-by: Paolo Bonzini

KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio

2021-07-14T16:17:56Z

BUG: KASAN: use-after-free in kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:183 Read of size 8 at addr ffff0000c03a2500 by task syz-executor083/4269 CPU: 5 PID: 4269 Comm: syz-executor083 Not tainted 5.10.0 #7 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x2d0 arch/arm64/kernel/stacktrace.c:132 show_stack+0x28/0x34 arch/arm64/kernel/stacktrace.c:196 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x110/0x164 lib/dump_stack.c:118 print_address_description+0x78/0x5c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report+0x148/0x1e4 mm/kasan/report.c:562 check_memory_region_inline mm/kasan/generic.c:183 [inline] __asan_load8+0xb4/0xbc mm/kasan/generic.c:252 kvm_vm_ioctl_unregister_coalesced_mmio+0x7c/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:183 kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3755 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Allocated by task 4269: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0xdc/0x120 mm/kasan/common.c:461 kasan_kmalloc+0xc/0x14 mm/kasan/common.c:475 kmem_cache_alloc_trace include/linux/slab.h:450 [inline] kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kvm_vm_ioctl_register_coalesced_mmio+0x78/0x1cc arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:146 kvm_vm_ioctl+0x7e8/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3746 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 Freed by task 4269: stack_trace_save+0x80/0xb8 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x38/0x6c mm/kasan/common.c:56 kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:355 __kasan_slab_free+0x124/0x150 mm/kasan/common.c:422 kasan_slab_free+0x10/0x1c mm/kasan/common.c:431 slab_free_hook mm/slub.c:1544 [inline] slab_free_freelist_hook mm/slub.c:1577 [inline] slab_free mm/slub.c:3142 [inline] kfree+0x104/0x38c mm/slub.c:4124 coalesced_mmio_destructor+0x94/0xa4 arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:102 kvm_iodevice_destructor include/kvm/iodev.h:61 [inline] kvm_io_bus_unregister_dev+0x248/0x280 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:4374 kvm_vm_ioctl_unregister_coalesced_mmio+0x158/0x1ec arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.c:186 kvm_vm_ioctl+0xe30/0x14c4 arch/arm64/kvm/../../../virt/kvm/kvm_main.c:3755 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __arm64_sys_ioctl+0xf88/0x131c fs/ioctl.c:739 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline] invoke_syscall arch/arm64/kernel/syscall.c:48 [inline] el0_svc_common arch/arm64/kernel/syscall.c:158 [inline] do_el0_svc+0x120/0x290 arch/arm64/kernel/syscall.c:220 el0_svc+0x1c/0x28 arch/arm64/kernel/entry-common.c:367 el0_sync_handler+0x98/0x170 arch/arm64/kernel/entry-common.c:383 el0_sync+0x140/0x180 arch/arm64/kernel/entry.S:670 If kvm_io_bus_unregister_dev() return -ENOMEM, we already call kvm_iodevice_destructor() inside this function to delete 'struct kvm_coalesced_mmio_dev *dev' from list and free the dev, but kvm_iodevice_destructor() is called again, it will lead the above issue. Let's check the the return value of kvm_io_bus_unregister_dev(), only call kvm_iodevice_destructor() if the return value is 0. Cc: Paolo Bonzini Cc: kvm@vger.kernel.org Reported-by: Hulk Robot Signed-off-by: Kefeng Wang Message-Id: <20210626070304.143456-1-wangkefeng.wang@huawei.com> Cc: stable@vger.kernel.org Fixes: 5d3c4c79384a ("KVM: Stop looking for coalesced MMIO zones if the bus is destroyed", 2021-04-20) Signed-off-by: Paolo Bonzini

Merge tag 'kvm-s390-master-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2021-07-14T16:14:27Z

KVM: selftests: Fixes - provide memory model for IBM z196 and zEC12 - do not require 64GB of memory

Merge branch 'akpm' (patches from Andrew)

2021-06-30T00:29:11Z

Merge misc updates from Andrew Morton: "191 patches. Subsystems affected by this patch series: kthread, ia64, scripts, ntfs, squashfs, ocfs2, kernel/watchdog, and mm (gup, pagealloc, slab, slub, kmemleak, dax, debug, pagecache, gup, swap, memcg, pagemap, mprotect, bootmem, dma, tracing, vmalloc, kasan, initialization, pagealloc, and memory-failure)" * emailed patches from Andrew Morton : (191 commits) mm,hwpoison: make get_hwpoison_page() call get_any_page() mm,hwpoison: send SIGBUS with error virutal address mm/page_alloc: split pcp->high across all online CPUs for cpuless nodes mm/page_alloc: allow high-order pages to be stored on the per-cpu lists mm: replace CONFIG_FLAT_NODE_MEM_MAP with CONFIG_FLATMEM mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA docs: remove description of DISCONTIGMEM arch, mm: remove stale mentions of DISCONIGMEM mm: remove CONFIG_DISCONTIGMEM m68k: remove support for DISCONTIGMEM arc: remove support for DISCONTIGMEM arc: update comment about HIGHMEM implementation alpha: remove DISCONTIGMEM and NUMA mm/page_alloc: move free_the_page mm/page_alloc: fix counting of managed_pages mm/page_alloc: improve memmap_pages dbg msg mm: drop SECTION_SHIFT in code comments mm/page_alloc: introduce vm.percpu_pagelist_high_fraction mm/page_alloc: limit the number of pages on PCP lists when reclaim is active mm/page_alloc: scale the number of pages that are batch freed ...

virt/kvm: use vma_lookup() instead of find_vma_intersection()

2021-06-29T17:53:51Z

vma_lookup() finds the vma of a specific address with a cleaner interface and is more readable. Link: https://lkml.kernel.org/r/20210521174745.2219620-11-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett Reviewed-by: Laurent Dufour Acked-by: David Hildenbrand Acked-by: Davidlohr Bueso Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2021-06-28T22:40:51Z

Pull kvm updates from Paolo Bonzini: "This covers all architectures (except MIPS) so I don't expect any other feature pull requests this merge window. ARM: - Add MTE support in guests, complete with tag save/restore interface - Reduce the impact of CMOs by moving them in the page-table code - Allow device block mappings at stage-2 - Reduce the footprint of the vmemmap in protected mode - Support the vGIC on dumb systems such as the Apple M1 - Add selftest infrastructure to support multiple configuration and apply that to PMU/non-PMU setups - Add selftests for the debug architecture - The usual crop of PMU fixes PPC: - Support for the H_RPT_INVALIDATE hypercall - Conversion of Book3S entry/exit to C - Bug fixes S390: - new HW facilities for guests - make inline assembly more robust with KASAN and co x86: - Allow userspace to handle emulation errors (unknown instructions) - Lazy allocation of the rmap (host physical -> guest physical address) - Support for virtualizing TSC scaling on VMX machines - Optimizations to avoid shattering huge pages at the beginning of live migration - Support for initializing the PDPTRs without loading them from memory - Many TLB flushing cleanups - Refuse to load if two-stage paging is available but NX is not (this has been a requirement in practice for over a year) - A large series that separates the MMU mode (WP/SMAP/SMEP etc.) from CR0/CR4/EFER, using the MMU mode everywhere once it is computed from the CPU registers - Use PM notifier to notify the guest about host suspend or hibernate - Support for passing arguments to Hyper-V hypercalls using XMM registers - Support for Hyper-V TLB flush hypercalls and enlightened MSR bitmap on AMD processors - Hide Hyper-V hypercalls that are not included in the guest CPUID - Fixes for live migration of virtual machines that use the Hyper-V "enlightened VMCS" optimization of nested virtualization - Bugfixes (not many) Generic: - Support for retrieving statistics without debugfs - Cleanups for the KVM selftests API" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (314 commits) KVM: x86: rename apic_access_page_done to apic_access_memslot_enabled kvm: x86: disable the narrow guest module parameter on unload selftests: kvm: Allows userspace to handle emulation errors. kvm: x86: Allow userspace to handle emulation errors KVM: x86/mmu: Let guest use GBPAGES if supported in hardware and TDP is on KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Get CR0.WP from MMU, not vCPU, in shadow page fault KVM: x86/mmu: Drop redundant rsvd bits reset for nested NPT KVM: x86/mmu: Optimize and clean up so called "last nonleaf level" logic KVM: x86: Enhance comments for MMU roles and nested transition trickiness KVM: x86/mmu: WARN on any reserved SPTE value when making a valid SPTE KVM: x86/mmu: Add helpers to do full reserved SPTE checks w/ generic MMU KVM: x86/mmu: Use MMU's role to determine PTTYPE KVM: x86/mmu: Collapse 32-bit PAE and 64-bit statements for helpers KVM: x86/mmu: Add a helper to calculate root from role_regs KVM: x86/mmu: Add helper to update paging metadata KVM: x86/mmu: Don't update nested guest's paging bitmasks if CR0.PG=0 KVM: x86/mmu: Consolidate reset_rsvds_bits_mask() calls KVM: x86/mmu: Use MMU role_regs to get LA57, and drop vCPU LA57 helper KVM: x86/mmu: Get nested MMU's root level from the MMU's role ...