- 29 Apr, 2022 6 commits
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Sean Christopherson authored
Drop lookup_address_in_mm() now that KVM is providing it's own variant of lookup_address_in_pgd() that is safe for use with user addresses, e.g. guards against page tables being torn down. A variant that provides a non-init mm is inherently dangerous and flawed, as the only reason to use an mm other than init_mm is to walk a userspace mapping, and lookup_address_in_pgd() does not play nice with userspace mappings, e.g. doesn't disable IRQs to block TLB shootdowns and doesn't use READ_ONCE() to ensure an upper level entry isn't converted to a huge page between checking the PAGE_SIZE bit and grabbing the address of the next level down. This reverts commit 13c72c06. Signed-off-by:
Sean Christopherson <seanjc@google.com> Message-Id: <YmwIi3bXr/1yhYV/@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini authored
Fixes for (relatively) old bugs, to be merged in both the -rc and next development trees: * Fix potential races when walking host page table * Fix bad user ABI for KVM_EXIT_SYSTEM_EVENT * Fix shadow page table leak when KVM runs nested
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Mingwei Zhang authored
KVM uses lookup_address_in_mm() to detect the hugepage size that the host uses to map a pfn. The function suffers from several issues: - no usage of READ_ONCE(*). This allows multiple dereference of the same page table entry. The TOCTOU problem because of that may cause KVM to incorrectly treat a newly generated leaf entry as a nonleaf one, and dereference the content by using its pfn value. - the information returned does not match what KVM needs; for non-present entries it returns the level at which the walk was terminated, as long as the entry is not 'none'. KVM needs level information of only 'present' entries, otherwise it may regard a non-present PXE entry as a present large page mapping. - the function is not safe for mappings that can be torn down, because it does not disable IRQs and because it returns a PTE pointer which is never safe to dereference after the function returns. So implement the logic for walking host page tables directly in KVM, and stop using lookup_address_in_mm(). Cc: Sean Christopherson <seanjc@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Mingwei Zhang <mizhang@google.com> Message-Id: <20220429031757.2042406-1-mizhang@google.com> [Inline in host_pfn_mapping_level, ensure no semantic change for its callers. - Paolo] Signed-off-by:
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Paolo Bonzini authored
When KVM_EXIT_SYSTEM_EVENT was introduced, it included a flags member that at the time was unused. Unfortunately this extensibility mechanism has several issues: - x86 is not writing the member, so it would not be possible to use it on x86 except for new events - the member is not aligned to 64 bits, so the definition of the uAPI struct is incorrect for 32- on 64-bit userspace. This is a problem for RISC-V, which supports CONFIG_KVM_COMPAT, but fortunately usage of flags was only introduced in 5.18. Since padding has to be introduced, place a new field in there that tells if the flags field is valid. To allow further extensibility, in fact, change flags to an array of 16 values, and store how many of the values are valid. The availability of the new ndata field is tied to a system capability; all architectures are changed to fill in the field. To avoid breaking compilation of userspace that was using the flags field, provide a userspace-only union to overlap flags with data[0]. The new field is placed at the same offset for both 32- and 64-bit userspace. Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Peter Gonda <pgonda@google.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by:
kernel test robot <lkp@intel.com> Message-Id: <20220422103013.34832-1-pbonzini@redhat.com> Signed-off-by:
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Sean Christopherson authored
Disallow memslots and MMIO SPTEs whose gpa range would exceed the host's MAXPHYADDR, i.e. don't create SPTEs for gfns that exceed host.MAXPHYADDR. The TDP MMU bounds its zapping based on host.MAXPHYADDR, and so if the guest, possibly with help from userspace, manages to coerce KVM into creating a SPTE for an "impossible" gfn, KVM will leak the associated shadow pages (page tables): WARNING: CPU: 10 PID: 1122 at arch/x86/kvm/mmu/tdp_mmu.c:57 kvm_mmu_uninit_tdp_mmu+0x4b/0x60 [kvm] Modules linked in: kvm_intel kvm irqbypass CPU: 10 PID: 1122 Comm: set_memory_regi Tainted: G W 5.18.0-rc1+ #293 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:kvm_mmu_uninit_tdp_mmu+0x4b/0x60 [kvm] Call Trace: <TASK> kvm_arch_destroy_vm+0x130/0x1b0 [kvm] kvm_destroy_vm+0x162/0x2d0 [kvm] kvm_vm_release+0x1d/0x30 [kvm] __fput+0x82/0x240 task_work_run+0x5b/0x90 exit_to_user_mode_prepare+0xd2/0xe0 syscall_exit_to_user_mode+0x1d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae </TASK> On bare metal, encountering an impossible gpa in the page fault path is well and truly impossible, barring CPU bugs, as the CPU will signal #PF during the gva=>gpa translation (or a similar failure when stuffing a physical address into e.g. the VMCS/VMCB). But if KVM is running as a VM itself, the MAXPHYADDR enumerated to KVM may not be the actual MAXPHYADDR of the underlying hardware, in which case the hardware will not fault on the illegal-from-KVM's-perspective gpa. Alternatively, KVM could continue allowing the dodgy behavior and simply zap the max possible range. But, for hosts with MAXPHYADDR < 52, that's a (minor) waste of cycles, and more importantly, KVM can't reasonably support impossible memslots when running on bare metal (or with an accurate MAXPHYADDR as a VM). Note, limiting the overhead by checking if KVM is running as a guest is not a safe option as the host isn't required to announce itself to the guest in any way, e.g. doesn't need to set the HYPERVISOR CPUID bit. A second alternative to disallowing the memslot behavior would be to disallow creating a VM with guest.MAXPHYADDR > host.MAXPHYADDR. That restriction is undesirable as there are legitimate use cases for doing so, e.g. using the highest host.MAXPHYADDR out of a pool of heterogeneous systems so that VMs can be migrated between hosts with different MAXPHYADDRs without running afoul of the allow_smaller_maxphyaddr mess. Note that any guest.MAXPHYADDR is valid with shadow paging, and it is even useful in order to test KVM with MAXPHYADDR=52 (i.e. without any reserved physical address bits). The now common kvm_mmu_max_gfn() is inclusive instead of exclusive. The memslot and TDP MMU code want an exclusive value, but the name implies the returned value is inclusive, and the MMIO path needs an inclusive check. Fixes: faaf05b0 ("kvm: x86/mmu: Support zapping SPTEs in the TDP MMU") Fixes: 524a1e4e ("KVM: x86/mmu: Don't leak non-leaf SPTEs when zapping all SPTEs") Cc: stable@vger.kernel.org Cc: Maxim Levitsky <mlevitsk@redhat.com> Cc: Ben Gardon <bgardon@google.com> Cc: David Matlack <dmatlack@google.com> Signed-off-by: -
Paolo Bonzini authored
Merge tag 'kvmarm-fixes-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.18, take #2 - Take care of faults occuring between the PARange and IPA range by injecting an exception - Fix S2 faults taken from a host EL0 in protected mode - Work around Oops caused by a PMU access from a 32bit guest when PMU has been created. This is a temporary bodge until we fix it for good.
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- 27 Apr, 2022 3 commits
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Marc Zyngier authored
When taking a translation fault for an IPA that is outside of the range defined by the hypervisor (between the HW PARange and the IPA range), we stupidly treat it as an IO and forward the access to userspace. Of course, userspace can't do much with it, and things end badly. Arguably, the guest is braindead, but we should at least catch the case and inject an exception. Check the faulting IPA against: - the sanitised PARange: inject an address size fault - the IPA size: inject an abort Reported-by:
Christoffer Dall <christoffer.dall@arm.com> Signed-off-by:
Marc Zyngier <maz@kernel.org>
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Alexandru Elisei authored
kvm->arch.arm_pmu is set when userspace attempts to set the first PMU attribute. As certain attributes are mandatory, arm_pmu ends up always being set to a valid arm_pmu, otherwise KVM will refuse to run the VCPU. However, this only happens if the VCPU has the PMU feature. If the VCPU doesn't have the feature bit set, kvm->arch.arm_pmu will be left uninitialized and equal to NULL. KVM doesn't do ID register emulation for 32-bit guests and accesses to the PMU registers aren't gated by the pmu_visibility() function. This is done to prevent injecting unexpected undefined exceptions in guests which have detected the presence of a hardware PMU. But even though the VCPU feature is missing, KVM still attempts to emulate certain aspects of the PMU when PMU registers are accessed. This leads to a NULL pointer dereference like this one, which happens on an odroid-c4 board when running the kvm-unit-tests pmu-cycle-counter test with kvmtool and without the PMU feature being set: [ 454.402699] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000150 [ 454.405865] Mem abort info: [ 454.408596] ESR = 0x96000004 [ 454.411638] EC = 0x25: DABT (current EL), IL = 32 bits [ 454.416901] SET = 0, FnV = 0 [ 454.419909] EA = 0, S1PTW = 0 [ 454.423010] FSC = 0x04: level 0 translation fault [ 454.427841] Data abort info: [ 454.430687] ISV = 0, ISS = 0x00000004 [ 454.434484] CM = 0, WnR = 0 [ 454.437404] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000c924000 [ 454.443800] [0000000000000150] pgd=0000000000000000, p4d=0000000000000000 [ 454.450528] Internal error: Oops: 96000004 [#1] PREEMPT SMP [ 454.456036] Modules linked in: [ 454.459053] CPU: 1 PID: 267 Comm: kvm-vcpu-0 Not tainted 5.18.0-rc4 #113 [ 454.465697] Hardware name: Hardkernel ODROID-C4 (DT) [ 454.470612] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 454.477512] pc : kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.482427] lr : kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.487775] sp : ffff80000a9839c0 [ 454.491050] x29: ffff80000a9839c0 x28: ffff000000a83a00 x27: 0000000000000000 [ 454.498127] x26: 0000000000000000 x25: 0000000000000000 x24: ffff00000a510000 [ 454.505198] x23: ffff000000a83a00 x22: ffff000003b01000 x21: 0000000000000000 [ 454.512271] x20: 000000000000001f x19: 00000000000003ff x18: 0000000000000000 [ 454.519343] x17: 000000008003fe98 x16: 0000000000000000 x15: 0000000000000000 [ 454.526416] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 454.533489] x11: 000000008003fdbc x10: 0000000000009d20 x9 : 000000000000001b [ 454.540561] x8 : 0000000000000000 x7 : 0000000000000d00 x6 : 0000000000009d00 [ 454.547633] x5 : 0000000000000037 x4 : 0000000000009d00 x3 : 0d09000000000000 [ 454.554705] x2 : 000000000000001f x1 : 0000000000000000 x0 : 0000000000000000 [ 454.561779] Call trace: [ 454.564191] kvm_pmu_event_mask.isra.0+0x14/0x74 [ 454.568764] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 454.573766] access_pmu_evtyper+0x128/0x170 [ 454.577905] perform_access+0x34/0x80 [ 454.581527] kvm_handle_cp_32+0x13c/0x160 [ 454.585495] kvm_handle_cp15_32+0x1c/0x30 [ 454.589462] handle_exit+0x70/0x180 [ 454.592912] kvm_arch_vcpu_ioctl_run+0x1c4/0x5e0 [ 454.597485] kvm_vcpu_ioctl+0x23c/0x940 [ 454.601280] __arm64_sys_ioctl+0xa8/0xf0 [ 454.605160] invoke_syscall+0x48/0x114 [ 454.608869] el0_svc_common.constprop.0+0xd4/0xfc [ 454.613527] do_el0_svc+0x28/0x90 [ 454.616803] el0_svc+0x34/0xb0 [ 454.619822] el0t_64_sync_handler+0xa4/0x130 [ 454.624049] el0t_64_sync+0x18c/0x190 [ 454.627675] Code: a9be7bfd 910003fd f9000bf3 52807ff3 (b9415001) [ 454.633714] ---[ end trace 0000000000000000 ]--- In this particular case, Linux hasn't detected the presence of a hardware PMU because the PMU node is missing from the DTB, so userspace would have been unable to set the VCPU PMU feature even if it attempted it. What happens is that the 32-bit guest reads ID_DFR0, which advertises the presence of the PMU, and when it tries to program a counter, it triggers the NULL pointer dereference because kvm->arch.arm_pmu is NULL. kvm-arch.arm_pmu was introduced by commit 46b18782 ("KVM: arm64: Keep a per-VM pointer to the default PMU"). Until that commit, this error would be triggered instead: [ 73.388140] ------------[ cut here ]------------ [ 73.388189] Unknown PMU version 0 [ 73.390420] WARNING: CPU: 1 PID: 264 at arch/arm64/kvm/pmu-emul.c:36 kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.399821] Modules linked in: [ 73.402835] CPU: 1 PID: 264 Comm: kvm-vcpu-0 Not tainted 5.17.0 #114 [ 73.409132] Hardware name: Hardkernel ODROID-C4 (DT) [ 73.414048] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 73.420948] pc : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.425863] lr : kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.430779] sp : ffff80000a8db9b0 [ 73.434055] x29: ffff80000a8db9b0 x28: ffff000000dbaac0 x27: 0000000000000000 [ 73.441131] x26: ffff000000dbaac0 x25: 00000000c600000d x24: 0000000000180720 [ 73.448203] x23: ffff800009ffbe10 x22: ffff00000b612000 x21: 0000000000000000 [ 73.455276] x20: 000000000000001f x19: 0000000000000000 x18: ffffffffffffffff [ 73.462348] x17: 000000008003fe98 x16: 0000000000000000 x15: 0720072007200720 [ 73.469420] x14: 0720072007200720 x13: ffff800009d32488 x12: 00000000000004e6 [ 73.476493] x11: 00000000000001a2 x10: ffff800009d32488 x9 : ffff800009d32488 [ 73.483565] x8 : 00000000ffffefff x7 : ffff800009d8a488 x6 : ffff800009d8a488 [ 73.490638] x5 : ffff0000f461a9d8 x4 : 0000000000000000 x3 : 0000000000000001 [ 73.497710] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000000dbaac0 [ 73.504784] Call trace: [ 73.507195] kvm_pmu_event_mask.isra.0+0x6c/0x74 [ 73.511768] kvm_pmu_set_counter_event_type+0x2c/0x80 [ 73.516770] access_pmu_evtyper+0x128/0x16c [ 73.520910] perform_access+0x34/0x80 [ 73.524532] kvm_handle_cp_32+0x13c/0x160 [ 73.528500] kvm_handle_cp15_32+0x1c/0x30 [ 73.532467] handle_exit+0x70/0x180 [ 73.535917] kvm_arch_vcpu_ioctl_run+0x20c/0x6e0 [ 73.540489] kvm_vcpu_ioctl+0x2b8/0x9e0 [ 73.544283] __arm64_sys_ioctl+0xa8/0xf0 [ 73.548165] invoke_syscall+0x48/0x114 [ 73.551874] el0_svc_common.constprop.0+0xd4/0xfc [ 73.556531] do_el0_svc+0x28/0x90 [ 73.559808] el0_svc+0x28/0x80 [ 73.562826] el0t_64_sync_handler+0xa4/0x130 [ 73.567054] el0t_64_sync+0x1a0/0x1a4 [ 73.570676] ---[ end trace 0000000000000000 ]--- [ 73.575382] kvm: pmu event creation failed -2 The root cause remains the same: kvm->arch.pmuver was never set to something sensible because the VCPU feature itself was never set. The odroid-c4 is somewhat of a special case, because Linux doesn't probe the PMU. But the above errors can easily be reproduced on any hardware, with or without a PMU driver, as long as userspace doesn't set the PMU feature. Work around the fact that KVM advertises a PMU even when the VCPU feature is not set by gating all PMU emulation on the feature. The guest can still access the registers without KVM injecting an undefined exception. Signed-off-by:
Alexandru Elisei <alexandru.elisei@arm.com> Signed-off-by:
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Will Deacon authored
When pKVM is enabled, host memory accesses are translated by an identity mapping at stage-2, which is populated lazily in response to synchronous exceptions from 64-bit EL1 and EL0. Extend this handling to cover exceptions originating from 32-bit EL0 as well. Although these are very unlikely to occur in practice, as the kernel typically ensures that user pages are initialised before mapping them in, drivers could still map previously untouched device pages into userspace and expect things to work rather than panic the system. Cc: Quentin Perret <qperret@google.com> Cc: Marc Zyngier <maz@kernel.org> Signed-off-by:
Will Deacon <will@kernel.org> Signed-off-by:
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- 21 Apr, 2022 18 commits
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Paolo Bonzini authored
Clean up code that was hardcoding masks for various fields, now that the masks are included in processor.h. For more cleanup, define PAGE_SIZE and PAGE_MASK just like in Linux. PAGE_SIZE in particular was defined by several tests. Suggested-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
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Paolo Bonzini authored
Red Hat's QE team reported test failure on access_tracking_perf_test: Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory offset: 0x3fffbffff000 Populating memory : 0.684014577s Writing to populated memory : 0.006230175s Reading from populated memory : 0.004557805s ==== Test Assertion Failure ==== lib/kvm_util.c:1411: false pid=125806 tid=125809 errno=4 - Interrupted system call 1 0x0000000000402f7c: addr_gpa2hva at kvm_util.c:1411 2 (inlined by) addr_gpa2hva at kvm_util.c:1405 3 0x0000000000401f52: lookup_pfn at access_tracking_perf_test.c:98 4 (inlined by) mark_vcpu_memory_idle at access_tracking_perf_test.c:152 5 (inlined by) vcpu_thread_main at access_tracking_perf_test.c:232 6 0x00007fefe9ff81ce: ?? ??:0 7 0x00007fefe9c64d82: ?? ??:0 No vm physical memory at 0xffbffff000 I can easily reproduce it with a Intel(R) Xeon(R) CPU E5-2630 with 46 bits PA. It turns out that the address translation for clearing idle page tracking returned a wrong result; addr_gva2gpa()'s last step, which is based on "pte[index[0]].pfn", did the calculation with 40 bits length and the high 12 bits got truncated. In above case the GPA address to be returned should be 0x3fffbffff000 for GVA 0xc0000000, but it got truncated into 0xffbffff000 and the subsequent gpa2hva lookup failed. The width of operations on bit fields greater than 32-bit is implementation defined, and differs between GCC (which uses the bitfield precision) and clang (which uses 64-bit arithmetic), so this is a potential minefield. Remove the bit fields and using manual masking instead. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2075036Reported-by:Nana Liu <nanliu@redhat.com> Reviewed-by:
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Mingwei Zhang authored
Flush the CPU caches when memory is reclaimed from an SEV guest (where reclaim also includes it being unmapped from KVM's memslots). Due to lack of coherency for SEV encrypted memory, failure to flush results in silent data corruption if userspace is malicious/broken and doesn't ensure SEV guest memory is properly pinned and unpinned. Cache coherency is not enforced across the VM boundary in SEV (AMD APM vol.2 Section 15.34.7). Confidential cachelines, generated by confidential VM guests have to be explicitly flushed on the host side. If a memory page containing dirty confidential cachelines was released by VM and reallocated to another user, the cachelines may corrupt the new user at a later time. KVM takes a shortcut by assuming all confidential memory remain pinned until the end of VM lifetime. Therefore, KVM does not flush cache at mmu_notifier invalidation events. Because of this incorrect assumption and the lack of cache flushing, malicous userspace can crash the host kernel: creating a malicious VM and continuously allocates/releases unpinned confidential memory pages when the VM is running. Add cache flush operations to mmu_notifier operations to ensure that any physical memory leaving the guest VM get flushed. In particular, hook mmu_notifier_invalidate_range_start and mmu_notifier_release events and flush cache accordingly. The hook after releasing the mmu lock to avoid contention with other vCPUs. Cc: stable@vger.kernel.org Suggested-by:
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Mingwei Zhang authored
Use clflush_cache_range() to flush the confidential memory when SME_COHERENT is supported in AMD CPU. Cache flush is still needed since SME_COHERENT only support cache invalidation at CPU side. All confidential cache lines are still incoherent with DMA devices. Cc: stable@vger.kerel.org Fixes: add5e2f0 ("KVM: SVM: Add support for the SEV-ES VMSA") Reviewed-by:
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Sean Christopherson authored
Rework sev_flush_guest_memory() to explicitly handle only a single page, and harden it to fall back to WBINVD if VM_PAGE_FLUSH fails. Per-page flushing is currently used only to flush the VMSA, and in its current form, the helper is completely broken with respect to flushing actual guest memory, i.e. won't work correctly for an arbitrary memory range. VM_PAGE_FLUSH takes a host virtual address, and is subject to normal page walks, i.e. will fault if the address is not present in the host page tables or does not have the correct permissions. Current AMD CPUs also do not honor SMAP overrides (undocumented in kernel versions of the APM), so passing in a userspace address is completely out of the question. In other words, KVM would need to manually walk the host page tables to get the pfn, ensure the pfn is stable, and then use the direct map to invoke VM_PAGE_FLUSH. And the latter might not even work, e.g. if userspace is particularly evil/clever and backs the guest with Secret Memory (which unmaps memory from the direct map). Signed-off-by:
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Thomas Huth authored
When compiling kvm_page_table_test.c, I get this compiler warning with gcc 11.2: kvm_page_table_test.c: In function 'pre_init_before_test': ../../../../tools/include/linux/kernel.h:44:24: warning: comparison of distinct pointer types lacks a cast 44 | (void) (&_max1 == &_max2); \ | ^~ kvm_page_table_test.c:281:21: note: in expansion of macro 'max' 281 | alignment = max(0x100000, alignment); | ^~~ Fix it by adjusting the type of the absolute value. Signed-off-by:Thomas Huth <thuth@redhat.com> Reviewed-by:
Claudio Imbrenda <imbrenda@linux.ibm.com> Message-Id: <20220414103031.565037-1-thuth@redhat.com> Signed-off-by:
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Like Xu authored
NMI-watchdog is one of the favorite features of kernel developers, but it does not work in AMD guest even with vPMU enabled and worse, the system misrepresents this capability via /proc. This is a PMC emulation error. KVM does not pass the latest valid value to perf_event in time when guest NMI-watchdog is running, thus the perf_event corresponding to the watchdog counter will enter the old state at some point after the first guest NMI injection, forcing the hardware register PMC0 to be constantly written to 0x800000000001. Meanwhile, the running counter should accurately reflect its new value based on the latest coordinated pmc->counter (from vPMC's point of view) rather than the value written directly by the guest. Fixes: 168d918f ("KVM: x86: Adjust counter sample period after a wrmsr") Reported-by:
Dongli Cao <caodongli@kingsoft.com> Signed-off-by:
Like Xu <likexu@tencent.com> Reviewed-by:
Yanan Wang <wangyanan55@huawei.com> Tested-by:
Jim Mattson <jmattson@google.com> Message-Id: <20220409015226.38619-1-likexu@tencent.com> Cc: stable@vger.kernel.org Signed-off-by:
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Wanpeng Li authored
MSR_KVM_POLL_CONTROL is cleared on reset, thus reverting guests to host-side polling after suspend/resume. Non-bootstrap CPUs are restored correctly by the haltpoll driver because they are hot-unplugged during suspend and hot-plugged during resume; however, the BSP is not hotpluggable and remains in host-sde polling mode after the guest resume. The makes the guest pay for the cost of vmexits every time the guest enters idle. Fix it by recording BSP's haltpoll state and resuming it during guest resume. Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by:
Wanpeng Li <wanpengli@tencent.com> Message-Id: <1650267752-46796-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Tom Rix authored
SPDX comments use use /* */ style comments in headers anad // style comments in .c files. Also fix two spelling mistakes. Signed-off-by:
Tom Rix <trix@redhat.com> Message-Id: <20220410153840.55506-1-trix@redhat.com> Signed-off-by:
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Sean Christopherson authored
Skip the APICv inhibit update for KVM_GUESTDBG_BLOCKIRQ if APICv is disabled at the module level to avoid having to acquire the mutex and potentially process all vCPUs. The DISABLE inhibit will (barring bugs) never be lifted, so piling on more inhibits is unnecessary. Fixes: cae72dcc ("KVM: x86: inhibit APICv when KVM_GUESTDBG_BLOCKIRQ active") Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220420013732.3308816-5-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Make a KVM_REQ_APICV_UPDATE request when creating a vCPU with an in-kernel local APIC and APICv enabled at the module level. Consuming kvm_apicv_activated() and stuffing vcpu->arch.apicv_active directly can race with __kvm_set_or_clear_apicv_inhibit(), as vCPU creation happens before the vCPU is fully onlined, i.e. it won't get the request made to "all" vCPUs. If APICv is globally inhibited between setting apicv_active and onlining the vCPU, the vCPU will end up running with APICv enabled and trigger KVM's sanity check. Mark APICv as active during vCPU creation if APICv is enabled at the module level, both to be optimistic about it's final state, e.g. to avoid additional VMWRITEs on VMX, and because there are likely bugs lurking since KVM checks apicv_active in multiple vCPU creation paths. While keeping the current behavior of consuming kvm_apicv_activated() is arguably safer from a regression perspective, force apicv_active so that vCPU creation runs with deterministic state and so that if there are bugs, they are found sooner than later, i.e. not when some crazy race condition is hit. WARNING: CPU: 0 PID: 484 at arch/x86/kvm/x86.c:9877 vcpu_enter_guest+0x2ae3/0x3ee0 arch/x86/kvm/x86.c:9877 Modules linked in: CPU: 0 PID: 484 Comm: syz-executor361 Not tainted 5.16.13 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1~cloud0 04/01/2014 RIP: 0010:vcpu_enter_guest+0x2ae3/0x3ee0 arch/x86/kvm/x86.c:9877 Call Trace: <TASK> vcpu_run arch/x86/kvm/x86.c:10039 [inline] kvm_arch_vcpu_ioctl_run+0x337/0x15e0 arch/x86/kvm/x86.c:10234 kvm_vcpu_ioctl+0x4d2/0xc80 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3727 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x16d/0x1d0 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The bug was hit by a syzkaller spamming VM creation with 2 vCPUs and a call to KVM_SET_GUEST_DEBUG. r0 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000000), 0x0, 0x0) r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0) ioctl$KVM_CAP_SPLIT_IRQCHIP(r1, 0x4068aea3, &(0x7f0000000000)) (async) r2 = ioctl$KVM_CREATE_VCPU(r1, 0xae41, 0x0) (async) r3 = ioctl$KVM_CREATE_VCPU(r1, 0xae41, 0x400000000000002) ioctl$KVM_SET_GUEST_DEBUG(r3, 0x4048ae9b, &(0x7f00000000c0)={0x5dda9c14aa95f5c5}) ioctl$KVM_RUN(r2, 0xae80, 0x0) Reported-by:Gaoning Pan <pgn@zju.edu.cn> Reported-by:
Yongkang Jia <kangel@zju.edu.cn> Fixes: 8df14af4 ("kvm: x86: Add support for dynamic APICv activation") Cc: stable@vger.kernel.org Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
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Sean Christopherson authored
Defer APICv updates that occur while L2 is active until nested VM-Exit, i.e. until L1 regains control. vmx_refresh_apicv_exec_ctrl() assumes L1 is active and (a) stomps all over vmcs02 and (b) neglects to ever updated vmcs01. E.g. if vmcs12 doesn't enable the TPR shadow for L2 (and thus no APICv controls), L1 performs nested VM-Enter APICv inhibited, and APICv becomes unhibited while L2 is active, KVM will set various APICv controls in vmcs02 and trigger a failed VM-Entry. The kicker is that, unless running with nested_early_check=1, KVM blames L1 and chaos ensues. In all cases, ignoring vmcs02 and always deferring the inhibition change to vmcs01 is correct (or at least acceptable). The ABSENT and DISABLE inhibitions cannot truly change while L2 is active (see below). IRQ_BLOCKING can change, but it is firmly a best effort debug feature. Furthermore, only L2's APIC is accelerated/virtualized to the full extent possible, e.g. even if L1 passes through its APIC to L2, normal MMIO/MSR interception will apply to the virtual APIC managed by KVM. The exception is the SELF_IPI register when x2APIC is enabled, but that's an acceptable hole. Lastly, Hyper-V's Auto EOI can technically be toggled if L1 exposes the MSRs to L2, but for that to work in any sane capacity, L1 would need to pass through IRQs to L2 as well, and IRQs must be intercepted to enable virtual interrupt delivery. I.e. exposing Auto EOI to L2 and enabling VID for L2 are, for all intents and purposes, mutually exclusive. Lack of dynamic toggling is also why this scenario is all but impossible to encounter in KVM's current form. But a future patch will pend an APICv update request _during_ vCPU creation to plug a race where a vCPU that's being created doesn't get included in the "all vCPUs request" because it's not yet visible to other vCPUs. If userspaces restores L2 after VM creation (hello, KVM selftests), the first KVM_RUN will occur while L2 is active and thus service the APICv update request made during VM creation. Cc: stable@vger.kernel.org Signed-off-by:
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Sean Christopherson authored
Set the DISABLE inhibit, not the ABSENT inhibit, if APICv is disabled via module param. A recent refactoring to add a wrapper for setting/clearing inhibits unintentionally changed the flag, probably due to a copy+paste goof. Fixes: 4f4c4a3e ("KVM: x86: Trace all APICv inhibit changes and capture overall status") Signed-off-by:
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Sean Christopherson authored
Initialize debugfs_entry to its semi-magical -ENOENT value when the VM is created. KVM's teardown when VM creation fails is kludgy and calls kvm_uevent_notify_change() and kvm_destroy_vm_debugfs() even if KVM never attempted kvm_create_vm_debugfs(). Because debugfs_entry is zero initialized, the IS_ERR() checks pass and KVM derefs a NULL pointer. BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1068b1067 P4D 1068b1067 PUD 1068b0067 PMD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 871 Comm: repro Not tainted 5.18.0-rc1+ #825 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:__dentry_path+0x7b/0x130 Call Trace: <TASK> dentry_path_raw+0x42/0x70 kvm_uevent_notify_change.part.0+0x10c/0x200 [kvm] kvm_put_kvm+0x63/0x2b0 [kvm] kvm_dev_ioctl+0x43a/0x920 [kvm] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x31/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xae </TASK> Modules linked in: kvm_intel kvm irqbypass Fixes: a44a4cc1 ("KVM: Don't create VM debugfs files outside of the VM directory") Cc: stable@vger.kernel.org Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oupton@google.com> Reported-by: syzbot+df6fbbd2ee39f21289ef@syzkaller.appspotmail.com Signed-off-by:
Oliver Upton <oupton@google.com> Message-Id: <20220415004622.2207751-1-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Add wrappers to acquire/release KVM's SRCU lock when stashing the index in vcpu->src_idx, along with rudimentary detection of illegal usage, e.g. re-acquiring SRCU and thus overwriting vcpu->src_idx. Because the SRCU index is (currently) either 0 or 1, illegal nesting bugs can go unnoticed for quite some time and only cause problems when the nested lock happens to get a different index. Wrap the WARNs in PROVE_RCU=y, and make them ONCE, otherwise KVM will likely yell so loudly that it will bring the kernel to its knees. Signed-off-by:
Fabiano Rosas <farosas@linux.ibm.com> Message-Id: <20220415004343.2203171-4-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Use the generic kvm_vcpu's srcu_idx instead of using an indentical field in RISC-V's version of kvm_vcpu_arch. Generic KVM very intentionally does not touch vcpu->srcu_idx, i.e. there's zero chance of running afoul of common code. Signed-off-by:
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Sean Christopherson authored
Don't re-acquire SRCU in complete_emulated_io() now that KVM acquires the lock in kvm_arch_vcpu_ioctl_run(). More importantly, don't overwrite vcpu->srcu_idx. If the index acquired by complete_emulated_io() differs from the one acquired by kvm_arch_vcpu_ioctl_run(), KVM will effectively leak a lock and hang if/when synchronize_srcu() is invoked for the relevant grace period. Fixes: 8d25b7be ("KVM: x86: pull kvm->srcu read-side to kvm_arch_vcpu_ioctl_run") Cc: stable@vger.kernel.org Signed-off-by:
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https://github.com/kvm-riscv/linuxPaolo Bonzini authored
KVM/riscv fixes for 5.18, take #2 - Remove 's' & 'u' as valid ISA extension - Do not allow disabling the base extensions 'i'/'m'/'a'/'c'
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- 20 Apr, 2022 2 commits
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Atish Patra authored
Currently, the config isa register allows us to disable all allowed single letter ISA extensions. It shouldn't be the case as vmm shouldn't be able to disable base extensions (imac). These extensions should always be enabled as long as they are enabled in the host ISA. Signed-off-by:
Atish Patra <atishp@rivosinc.com> Signed-off-by:
Anup Patel <anup@brainfault.org> Fixes: 92ad8200 ("RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls")
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Atish Patra authored
There are no ISA extension defined as 's' & 'u' in RISC-V specifications. The misa register defines 's' & 'u' bit as Supervisor/User privilege mode enabled. But it should not appear in the ISA extension in the device tree. Remove those from the allowed ISA extension for kvm. Fixes: a33c72fa ("RISC-V: KVM: Implement VCPU create, init and destroy functions") Signed-off-by:
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- 17 Apr, 2022 10 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tipLinus Torvalds authored
Pull xen fixlet from Juergen Gross: "A single cleanup patch for the Xen balloon driver" * tag 'for-linus-5.18-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/balloon: don't use PV mode extra memory for zone device allocations
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "Two x86 fixes related to TSX: - Use either MSR_TSX_FORCE_ABORT or MSR_IA32_TSX_CTRL to disable TSX to cover all CPUs which allow to disable it. - Disable TSX development mode at boot so that a microcode update which provides TSX development mode does not suddenly make the system vulnerable to TSX Asynchronous Abort" * tag 'x86-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tsx: Disable TSX development mode at boot x86/tsx: Use MSR_TSX_CTRL to clear CPUID bits -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timer fixes from Thomas Gleixner: "A small set of fixes for the timers core: - Fix the warning condition in __run_timers() which does not take into account that a CPU base (especially the deferrable base) never has a timer armed on it and therefore the next_expiry value can become stale. - Replace a WARN_ON() in the NOHZ code with a WARN_ON_ONCE() to prevent endless spam in dmesg. - Remove the double star from a comment which is not meant to be in kernel-doc format" * tag 'timers-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick/sched: Fix non-kernel-doc comment tick/nohz: Use WARN_ON_ONCE() to prevent console saturation timers: Fix warning condition in __run_timers() -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull SMP fixes from Thomas Gleixner: "Two fixes for the SMP core: - Make the warning condition in flush_smp_call_function_queue() correct, which checked a just emptied list head for being empty instead of validating that there was no pending entry on the offlined CPU at all. - The @cpu member of struct cpuhp_cpu_state is initialized when the CPU hotplug thread for the upcoming CPU is created. That's too late because the creation of the thread can fail and then the following rollback operates on CPU0. Get rid of the CPU member and hand the CPU number to the involved functions directly" * tag 'smp-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Remove the 'cpu' member of cpuhp_cpu_state smp: Fix offline cpu check in flush_smp_call_function_queue() -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irq fix from Thomas Gleixner: "A single fix for the interrupt affinity spreading logic to take into account that there can be an imbalance between present and possible CPUs, which causes already assigned bits to be overwritten" * tag 'irq-urgent-2022-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq/affinity: Consider that CPUs on nodes can be unbalanced
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git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supplyLinus Torvalds authored
Pull power supply fixes from Sebastian Reichel: - Fix a regression with battery data failing to load from DT * tag 'for-v5.18-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply: power: supply: Reset err after not finding static battery power: supply: samsung-sdi-battery: Add missing charge restart voltages
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linuxLinus Torvalds authored
Pull i2c fixes from Wolfram Sang: "Regular set of fixes for drivers and the dev-interface" * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: ismt: Fix undefined behavior due to shift overflowing the constant i2c: dev: Force case user pointers in compat_i2cdev_ioctl() i2c: dev: check return value when calling dev_set_name() i2c: qcom-geni: Use dev_err_probe() for GPI DMA error i2c: imx: Implement errata ERR007805 or e7805 bus frequency limit i2c: pasemi: Wait for write xfers to finish
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git://git.kernel.org/pub/scm/linux/kernel/git/robh/linuxLinus Torvalds authored
Pull devicetree fixes from Rob Herring: - Fix scalar property schemas with array constraints - Fix 'enum' lists with duplicate entries - Fix incomplete if/then/else schemas - Add Renesas RZ/V2L SoC support to Mali Bifrost binding - Maintainers update for Marvell irqchip * tag 'devicetree-fixes-for-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: dt-bindings: display: panel-timing: Define a single type for properties dt-bindings: Fix array constraints on scalar properties dt-bindings: gpu: mali-bifrost: Document RZ/V2L SoC dt-bindings: net: snps: remove duplicate name dt-bindings: Fix 'enum' lists with duplicate entries dt-bindings: irqchip: mrvl,intc: refresh maintainers dt-bindings: Fix incomplete if/then/else schemas dt-bindings: power: renesas,apmu: Fix cpus property limits dt-bindings: extcon: maxim,max77843: fix ports type
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git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linuxLinus Torvalds authored
Pull gpio fixes from Bartosz Golaszewski: "A single fix for gpio-sim and two patches for GPIO ACPI pulled from Andy: - fix the set/get_multiple() callbacks in gpio-sim - use correct format characters in gpiolib-acpi - use an unsigned type for pins in gpiolib-acpi" * tag 'gpio-fixes-for-v5.18-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: gpio: sim: fix setting and getting multiple lines gpiolib: acpi: Convert type for pin to be unsigned gpiolib: acpi: use correct format characters
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- 16 Apr, 2022 1 commit
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git://git.kernel.org/pub/scm/linux/kernel/git/soc/socLinus Torvalds authored
Pull ARM SoC fixes from Arnd Bergmann: "There are a number of SoC bugfixes that came in since the merge window, and more of them are already pending. This batch includes: - A boot time regression fix for davinci that triggered on multi_v5_defconfig when booting any platform - Defconfig updates to address removed features, changed symbol names or dependencies, for gemini, ux500, and pxa - Email address changes for Krzysztof Kozlowski - Build warning fixes for ep93xx and iop32x - Devicetree warning fixes across many platforms - Minor bugfixes for the reset controller, memory controller and SCMI firmware subsystems plus the versatile-express board" * tag 'soc-fixes-5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (34 commits) ARM: config: Update Gemini defconfig arm64: dts: qcom/sdm845-shift-axolotl: Fix boolean properties with values ARM: dts: align SPI NOR node name with dtschema ARM: dts: Fix more boolean properties with values arm/arm64: dts: qcom: Fix boolean properties with values arm64: dts: imx: Fix imx8*-var-som touchscreen property sizes arm: dts: imx: Fix boolean properties with values arm64: dts: tegra: Fix boolean properties with values arm: dts: at91: Fix boolean properties with values arm: configs: imote2: Drop defconfig as board support dropped. ep93xx: clock: Don't use plain integer as NULL pointer ep93xx: clock: Fix UAF in ep93xx_clk_register_gate() ARM: vexpress/spc: Fix all the kernel-doc build warnings ARM: vexpress/spc: Fix kernel-doc build warning for ve_spc_cpu_in_wfi ARM: config: u8500: Re-enable AB8500 battery charging ARM: config: u8500: Add some common hardware memory: fsl_ifc: populate child nodes of buses and mfd devices ARM: config: Refresh U8500 defconfig firmware: arm_scmi: Fix sparse warnings in OPTEE transport driver firmware: arm_scmi: Replace zero-length array with flexible-array member ...
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