kernel/arch/arm64/mm/fault.c, branch linux-6.2.y

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

2022-12-15T19:12:21Z

Pull kvm updates from Paolo Bonzini: "ARM64: - Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. - Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. - Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on (see merge commit 382b5b87a97d: "Fix a number of issues with MTE, such as races on the tags being initialised vs the PG_mte_tagged flag as well as the lack of support for VM_SHARED when KVM is involved. Patches from Catalin Marinas and Peter Collingbourne"). - Merge the pKVM shadow vcpu state tracking that allows the hypervisor to have its own view of a vcpu, keeping that state private. - Add support for the PMUv3p5 architecture revision, bringing support for 64bit counters on systems that support it, and fix the no-quite-compliant CHAIN-ed counter support for the machines that actually exist out there. - Fix a handful of minor issues around 52bit VA/PA support (64kB pages only) as a prefix of the oncoming support for 4kB and 16kB pages. - Pick a small set of documentation and spelling fixes, because no good merge window would be complete without those. s390: - Second batch of the lazy destroy patches - First batch of KVM changes for kernel virtual != physical address support - Removal of a unused function x86: - Allow compiling out SMM support - Cleanup and documentation of SMM state save area format - Preserve interrupt shadow in SMM state save area - Respond to generic signals during slow page faults - Fixes and optimizations for the non-executable huge page errata fix. - Reprogram all performance counters on PMU filter change - Cleanups to Hyper-V emulation and tests - Process Hyper-V TLB flushes from a nested guest (i.e. from a L2 guest running on top of a L1 Hyper-V hypervisor) - Advertise several new Intel features - x86 Xen-for-KVM: - Allow the Xen runstate information to cross a page boundary - Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured - Add support for 32-bit guests in SCHEDOP_poll - Notable x86 fixes and cleanups: - One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0). - Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few years back when eliminating unnecessary barriers when switching between vmcs01 and vmcs02. - Clean up vmread_error_trampoline() to make it more obvious that params must be passed on the stack, even for x86-64. - Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective of the current guest CPUID. - Fudge around a race with TSC refinement that results in KVM incorrectly thinking a guest needs TSC scaling when running on a CPU with a constant TSC, but no hardware-enumerated TSC frequency. - Advertise (on AMD) that the SMM_CTL MSR is not supported - Remove unnecessary exports Generic: - Support for responding to signals during page faults; introduces new FOLL_INTERRUPTIBLE flag that was reviewed by mm folks Selftests: - Fix an inverted check in the access tracking perf test, and restore support for asserting that there aren't too many idle pages when running on bare metal. - Fix build errors that occur in certain setups (unsure exactly what is unique about the problematic setup) due to glibc overriding static_assert() to a variant that requires a custom message. - Introduce actual atomics for clear/set_bit() in selftests - Add support for pinning vCPUs in dirty_log_perf_test. - Rename the so called "perf_util" framework to "memstress". - Add a lightweight psuedo RNG for guest use, and use it to randomize the access pattern and write vs. read percentage in the memstress tests. - Add a common ucall implementation; code dedup and pre-work for running SEV (and beyond) guests in selftests. - Provide a common constructor and arch hook, which will eventually be used by x86 to automatically select the right hypercall (AMD vs. Intel). - A bunch of added/enabled/fixed selftests for ARM64, covering memslots, breakpoints, stage-2 faults and access tracking. - x86-specific selftest changes: - Clean up x86's page table management. - Clean up and enhance the "smaller maxphyaddr" test, and add a related test to cover generic emulation failure. - Clean up the nEPT support checks. - Add X86_PROPERTY_* framework to retrieve multi-bit CPUID values. - Fix an ordering issue in the AMX test introduced by recent conversions to use kvm_cpu_has(), and harden the code to guard against similar bugs in the future. Anything that tiggers caching of KVM's supported CPUID, kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if the caching occurs before the test opts in via prctl(). Documentation: - Remove deleted ioctls from documentation - Clean up the docs for the x86 MSR filter. - Various fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (361 commits) KVM: x86: Add proper ReST tables for userspace MSR exits/flags KVM: selftests: Allocate ucall pool from MEM_REGION_DATA KVM: arm64: selftests: Align VA space allocator with TTBR0 KVM: arm64: Fix benign bug with incorrect use of VA_BITS KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow KVM: x86: Advertise that the SMM_CTL MSR is not supported KVM: x86: remove unnecessary exports KVM: selftests: Fix spelling mistake "probabalistic" -> "probabilistic" tools: KVM: selftests: Convert clear/set_bit() to actual atomics tools: Drop "atomic_" prefix from atomic test_and_set_bit() tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests perf tools: Use dedicated non-atomic clear/set bit helpers tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers KVM: arm64: selftests: Enable single-step without a "full" ucall() KVM: x86: fix APICv/x2AVIC disabled when vm reboot by itself KVM: Remove stale comment about KVM_REQ_UNHALT KVM: Add missing arch for KVM_CREATE_DEVICE and KVM_{SET,GET}_DEVICE_ATTR KVM: Reference to kvm_userspace_memory_region in doc and comments KVM: Delete all references to removed KVM_SET_MEMORY_ALIAS ioctl ...

Merge tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

2022-12-13T22:31:47Z

Pull EFI updates from Ard Biesheuvel: "Another fairly sizable pull request, by EFI subsystem standards. Most of the work was done by me, some of it in collaboration with the distro and bootloader folks (GRUB, systemd-boot), where the main focus has been on removing pointless per-arch differences in the way EFI boots a Linux kernel. - Refactor the zboot code so that it incorporates all the EFI stub logic, rather than calling the decompressed kernel as a EFI app. - Add support for initrd= command line option to x86 mixed mode. - Allow initrd= to be used with arbitrary EFI accessible file systems instead of just the one the kernel itself was loaded from. - Move some x86-only handling and manipulation of the EFI memory map into arch/x86, as it is not used anywhere else. - More flexible handling of any random seeds provided by the boot environment (i.e., systemd-boot) so that it becomes available much earlier during the boot. - Allow improved arch-agnostic EFI support in loaders, by setting a uniform baseline of supported features, and adding a generic magic number to the DOS/PE header. This should allow loaders such as GRUB or systemd-boot to reduce the amount of arch-specific handling substantially. - (arm64) Run EFI runtime services from a dedicated stack, and use it to recover from synchronous exceptions that might occur in the firmware code. - (arm64) Ensure that we don't allocate memory outside of the 48-bit addressable physical range. - Make EFI pstore record size configurable - Add support for decoding CXL specific CPER records" * tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits) arm64: efi: Recover from synchronous exceptions occurring in firmware arm64: efi: Execute runtime services from a dedicated stack arm64: efi: Limit allocations to 48-bit addressable physical region efi: Put Linux specific magic number in the DOS header efi: libstub: Always enable initrd command line loader and bump version efi: stub: use random seed from EFI variable efi: vars: prohibit reading random seed variables efi: random: combine bootloader provided RNG seed with RNG protocol output efi/cper, cxl: Decode CXL Error Log efi/cper, cxl: Decode CXL Protocol Error Section efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment efi: x86: Move EFI runtime map sysfs code to arch/x86 efi: runtime-maps: Clarify purpose and enable by default for kexec efi: pstore: Add module parameter for setting the record size efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures efi: memmap: Move manipulation routines into x86 arch tree efi: memmap: Move EFI fake memmap support into x86 arch tree efi: libstub: Undeprecate the command line initrd loader efi: libstub: Add mixed mode support to command line initrd loader efi: libstub: Permit mixed mode return types other than efi_status_t ...

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2022-12-12T17:50:05Z

Pull arm64 updates from Will Deacon: "The highlights this time are support for dynamically enabling and disabling Clang's Shadow Call Stack at boot and a long-awaited optimisation to the way in which we handle the SVE register state on system call entry to avoid taking unnecessary traps from userspace. Summary: ACPI: - Enable FPDT support for boot-time profiling - Fix CPU PMU probing to work better with PREEMPT_RT - Update SMMUv3 MSI DeviceID parsing to latest IORT spec - APMT support for probing Arm CoreSight PMU devices CPU features: - Advertise new SVE instructions (v2.1) - Advertise range prefetch instruction - Advertise CSSC ("Common Short Sequence Compression") scalar instructions, adding things like min, max, abs, popcount - Enable DIT (Data Independent Timing) when running in the kernel - More conversion of system register fields over to the generated header CPU misfeatures: - Workaround for Cortex-A715 erratum #2645198 Dynamic SCS: - Support for dynamic shadow call stacks to allow switching at runtime between Clang's SCS implementation and the CPU's pointer authentication feature when it is supported (complete with scary DWARF parser!) Tracing and debug: - Remove static ftrace in favour of, err, dynamic ftrace! - Seperate 'struct ftrace_regs' from 'struct pt_regs' in core ftrace and existing arch code - Introduce and implement FTRACE_WITH_ARGS on arm64 to replace the old FTRACE_WITH_REGS - Extend 'crashkernel=' parameter with default value and fallback to placement above 4G physical if initial (low) allocation fails SVE: - Optimisation to avoid disabling SVE unconditionally on syscall entry and just zeroing the non-shared state on return instead Exceptions: - Rework of undefined instruction handling to avoid serialisation on global lock (this includes emulation of user accesses to the ID registers) Perf and PMU: - Support for TLP filters in Hisilicon's PCIe PMU device - Support for the DDR PMU present in Amlogic Meson G12 SoCs - Support for the terribly-named "CoreSight PMU" architecture from Arm (and Nvidia's implementation of said architecture) Misc: - Tighten up our boot protocol for systems with memory above 52 bits physical - Const-ify static keys to satisty jump label asm constraints - Trivial FFA driver cleanups in preparation for v1.1 support - Export the kernel_neon_* APIs as GPL symbols - Harden our instruction generation routines against instrumentation - A bunch of robustness improvements to our arch-specific selftests - Minor cleanups and fixes all over (kbuild, kprobes, kfence, PMU, ...)" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (151 commits) arm64: kprobes: Return DBG_HOOK_ERROR if kprobes can not handle a BRK arm64: kprobes: Let arch do_page_fault() fix up page fault in user handler arm64: Prohibit instrumentation on arch_stack_walk() arm64:uprobe fix the uprobe SWBP_INSN in big-endian arm64: alternatives: add __init/__initconst to some functions/variables arm_pmu: Drop redundant armpmu->map_event() in armpmu_event_init() kselftest/arm64: Allow epoll_wait() to return more than one result kselftest/arm64: Don't drain output while spawning children kselftest/arm64: Hold fp-stress children until they're all spawned arm64/sysreg: Remove duplicate definitions from asm/sysreg.h arm64/sysreg: Convert ID_DFR1_EL1 to automatic generation arm64/sysreg: Convert ID_DFR0_EL1 to automatic generation arm64/sysreg: Convert ID_AFR0_EL1 to automatic generation arm64/sysreg: Convert ID_MMFR5_EL1 to automatic generation arm64/sysreg: Convert MVFR2_EL1 to automatic generation arm64/sysreg: Convert MVFR1_EL1 to automatic generation arm64/sysreg: Convert MVFR0_EL1 to automatic generation arm64/sysreg: Convert ID_PFR2_EL1 to automatic generation arm64/sysreg: Convert ID_PFR1_EL1 to automatic generation arm64/sysreg: Convert ID_PFR0_EL1 to automatic generation ...

arm64: efi: Recover from synchronous exceptions occurring in firmware

2022-12-08T17:33:34Z

Unlike x86, which has machinery to deal with page faults that occur during the execution of EFI runtime services, arm64 has nothing like that, and a synchronous exception raised by firmware code brings down the whole system. With more EFI based systems appearing that were not built to run Linux (such as the Windows-on-ARM laptops based on Qualcomm SOCs), as well as the introduction of PRM (platform specific firmware routines that are callable just like EFI runtime services), we are more likely to run into issues of this sort, and it is much more likely that we can identify and work around such issues if they don't bring down the system entirely. Since we already use a EFI runtime services call wrapper in assembler, we can quite easily add some code that captures the execution state at the point where the call is made, allowing us to revert to this state and proceed execution if the call triggered a synchronous exception. Given that the kernel and the firmware don't share any data structures that could end up in an indeterminate state, we can happily continue running, as long as we mark the EFI runtime services as unavailable from that point on. Signed-off-by: Ard Biesheuvel Acked-by: Catalin Marinas

Merge branch kvm-arm64/mte-map-shared into kvmarm-master/next

2022-12-05T14:38:24Z

* kvm-arm64/mte-map-shared: : . : Update the MTE support to allow the VMM to use shared mappings : to back the memslots exposed to MTE-enabled guests. : : Patches courtesy of Catalin Marinas and Peter Collingbourne. : . : Fix a number of issues with MTE, such as races on the tags : being initialised vs the PG_mte_tagged flag as well as the : lack of support for VM_SHARED when KVM is involved. : : Patches from Catalin Marinas and Peter Collingbourne. : . Documentation: document the ABI changes for KVM_CAP_ARM_MTE KVM: arm64: permit all VM_MTE_ALLOWED mappings with MTE enabled KVM: arm64: unify the tests for VMAs in memslots when MTE is enabled arm64: mte: Lock a page for MTE tag initialisation mm: Add PG_arch_3 page flag KVM: arm64: Simplify the sanitise_mte_tags() logic arm64: mte: Fix/clarify the PG_mte_tagged semantics mm: Do not enable PG_arch_2 for all 64-bit architectures Signed-off-by: Marc Zyngier

arm64: efi: Revert "Recover from synchronous exceptions ..."

2022-12-01T13:48:26Z

This reverts commit 23715a26c8d81291, which introduced some code in assembler that manipulates both the ordinary and the shadow call stack pointer in a way that could potentially be taken advantage of. So let's revert it, and do a better job the next time around. Signed-off-by: Ard Biesheuvel

arm64: mte: Lock a page for MTE tag initialisation

2022-11-29T09:26:07Z

Initialising the tags and setting PG_mte_tagged flag for a page can race between multiple set_pte_at() on shared pages or setting the stage 2 pte via user_mem_abort(). Introduce a new PG_mte_lock flag as PG_arch_3 and set it before attempting page initialisation. Given that PG_mte_tagged is never cleared for a page, consider setting this flag to mean page unlocked and wait on this bit with acquire semantics if the page is locked: - try_page_mte_tagging() - lock the page for tagging, return true if it can be tagged, false if already tagged. No acquire semantics if it returns true (PG_mte_tagged not set) as there is no serialisation with a previous set_page_mte_tagged(). - set_page_mte_tagged() - set PG_mte_tagged with release semantics. The two-bit locking is based on Peter Collingbourne's idea. Signed-off-by: Catalin Marinas Signed-off-by: Peter Collingbourne Reviewed-by: Steven Price Cc: Will Deacon Cc: Marc Zyngier Cc: Peter Collingbourne Reviewed-by: Cornelia Huck Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221104011041.290951-6-pcc@google.com

arm64: mte: Fix/clarify the PG_mte_tagged semantics

2022-11-29T09:26:07Z

Currently the PG_mte_tagged page flag mostly means the page contains valid tags and it should be set after the tags have been cleared or restored. However, in mte_sync_tags() it is set before setting the tags to avoid, in theory, a race with concurrent mprotect(PROT_MTE) for shared pages. However, a concurrent mprotect(PROT_MTE) with a copy on write in another thread can cause the new page to have stale tags. Similarly, tag reading via ptrace() can read stale tags if the PG_mte_tagged flag is set before actually clearing/restoring the tags. Fix the PG_mte_tagged semantics so that it is only set after the tags have been cleared or restored. This is safe for swap restoring into a MAP_SHARED or CoW page since the core code takes the page lock. Add two functions to test and set the PG_mte_tagged flag with acquire and release semantics. The downside is that concurrent mprotect(PROT_MTE) on a MAP_SHARED page may cause tag loss. This is already the case for KVM guests if a VMM changes the page protection while the guest triggers a user_mem_abort(). Signed-off-by: Catalin Marinas [pcc@google.com: fix build with CONFIG_ARM64_MTE disabled] Signed-off-by: Peter Collingbourne Reviewed-by: Cornelia Huck Reviewed-by: Steven Price Cc: Will Deacon Cc: Marc Zyngier Cc: Peter Collingbourne Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20221104011041.290951-3-pcc@google.com

arm64: mm: kfence: only handle translation faults

2022-11-15T13:29:05Z

Alexander noted that KFENCE only expects to handle faults from invalid page table entries (i.e. translation faults), but arm64's fault handling logic will call kfence_handle_page_fault() for other types of faults, including alignment faults caused by unaligned atomics. This has the unfortunate property of causing those other faults to be reported as "KFENCE: use-after-free", which is misleading and hinders debugging. Fix this by only forwarding unhandled translation faults to the KFENCE code, similar to what x86 does already. Alexander has verified that this passes all the tests in the KFENCE test suite and avoids bogus reports on misaligned atomics. Link: https://lore.kernel.org/all/20221102081620.1465154-1-zhongbaisong@huawei.com/ Fixes: 840b23986344 ("arm64, kfence: enable KFENCE for ARM64") Signed-off-by: Mark Rutland Reviewed-by: Alexander Potapenko Tested-by: Alexander Potapenko Cc: Catalin Marinas Cc: Marco Elver Cc: Will Deacon Link: https://lore.kernel.org/r/20221114104411.2853040-1-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: efi: Recover from synchronous exceptions occurring in firmware

2022-11-03T17:01:15Z