KVM/arm64 changes for 6.17, take #2 - Correctly handle 'invariant' system registers for protected VMs - Improved handling of VNCR data aborts, including external aborts - Fixes for handling of FEAT_RAS for NV guests, providing a sane fault context during SEA injection and preventing the use of RASv1p1 fault injection hardware - Ensure that page table destruction when a VM is destroyed gives an opportunity to reschedule - Large fix to KVM's infrastructure for managing guest context loaded on the CPU, addressing issues where the output of AT emulation doesn't get reflected to the guest - Fix AT S12 emulation to actually perform stage-2 translation when necessary - Avoid attempting vLPI irqbypass when GICv4 has been explicitly disabled for a VM - Minor KVM + selftest fixes
When we added coverage for ID_AA64MMFR3_EL1 we didn't add it to the list
of registers we read in the guest, do so.
Fixes: 0b593ef12afc ("KVM: arm64: selftests: Catch up set_id_regs with the kernel")
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250818-kvm-arm64-selftests-mmfr3-idreg-v1-1-2f85114d0163@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
The ARM64_FEATURE_MASK() macro was a hack introduce whilst the automatic generation of sysreg encoding was introduced, and was too unreliable to be entirely trusted. We are in a better place now, and we could really do without this macro. Get rid of it altogether. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20250817202158.395078-7-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Tinkering with UUIDs is a perilious task, and the KVM UUID gets broken at times. In order to spot this early enough, add a selftest that will shout if the expected value isn't found. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Sebastian Ott <sebott@redhat.com> Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com Link: https://lore.kernel.org/r/20250806171341.1521210-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Pull kvm updates from Paolo Bonzini:
"ARM:
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on
hardware that previously advertised it unconditionally
- Map supporting endpoints with cacheable memory attributes on
systems with FEAT_S2FWB and DIC where KVM no longer needs to
perform cache maintenance on the address range
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the
guest hypervisor to inject external aborts into an L2 VM and take
traps of masked external aborts to the hypervisor
- Convert more system register sanitization to the config-driven
implementation
- Fixes to the visibility of EL2 registers, namely making VGICv3
system registers accessible through the VGIC device instead of the
ONE_REG vCPU ioctls
- Various cleanups and minor fixes
LoongArch:
- Add stat information for in-kernel irqchip
- Add tracepoints for CPUCFG and CSR emulation exits
- Enhance in-kernel irqchip emulation
- Various cleanups
RISC-V:
- Enable ring-based dirty memory tracking
- Improve perf kvm stat to report interrupt events
- Delegate illegal instruction trap to VS-mode
- MMU improvements related to upcoming nested virtualization
s390x
- Fixes
x86:
- Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O
APIC, PIC, and PIT emulation at compile time
- Share device posted IRQ code between SVM and VMX and harden it
against bugs and runtime errors
- Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups
O(1) instead of O(n)
- For MMIO stale data mitigation, track whether or not a vCPU has
access to (host) MMIO based on whether the page tables have MMIO
pfns mapped; using VFIO is prone to false negatives
- Rework the MSR interception code so that the SVM and VMX APIs are
more or less identical
- Recalculate all MSR intercepts from scratch on MSR filter changes,
instead of maintaining shadow bitmaps
- Advertise support for LKGS (Load Kernel GS base), a new instruction
that's loosely related to FRED, but is supported and enumerated
independently
- Fix a user-triggerable WARN that syzkaller found by setting the
vCPU in INIT_RECEIVED state (aka wait-for-SIPI), and then putting
the vCPU into VMX Root Mode (post-VMXON). Trying to detect every
possible path leading to architecturally forbidden states is hard
and even risks breaking userspace (if it goes from valid to valid
state but passes through invalid states), so just wait until
KVM_RUN to detect that the vCPU state isn't allowed
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling
interception of APERF/MPERF reads, so that a "properly" configured
VM can access APERF/MPERF. This has many caveats (APERF/MPERF
cannot be zeroed on vCPU creation or saved/restored on suspend and
resume, or preserved over thread migration let alone VM migration)
but can be useful whenever you're interested in letting Linux
guests see the effective physical CPU frequency in /proc/cpuinfo
- Reject KVM_SET_TSC_KHZ for vm file descriptors if vCPUs have been
created, as there's no known use case for changing the default
frequency for other VM types and it goes counter to the very reason
why the ioctl was added to the vm file descriptor. And also, there
would be no way to make it work for confidential VMs with a
"secure" TSC, so kill two birds with one stone
- Dynamically allocation the shadow MMU's hashed page list, and defer
allocating the hashed list until it's actually needed (the TDP MMU
doesn't use the list)
- Extract many of KVM's helpers for accessing architectural local
APIC state to common x86 so that they can be shared by guest-side
code for Secure AVIC
- Various cleanups and fixes
x86 (Intel):
- Preserve the host's DEBUGCTL.FREEZE_IN_SMM when running the guest.
Failure to honor FREEZE_IN_SMM can leak host state into guests
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter to
prevent L1 from running L2 with features that KVM doesn't support,
e.g. BTF
x86 (AMD):
- WARN and reject loading kvm-amd.ko instead of panicking the kernel
if the nested SVM MSRPM offsets tracker can't handle an MSR (which
is pretty much a static condition and therefore should never
happen, but still)
- Fix a variety of flaws and bugs in the AVIC device posted IRQ code
- Inhibit AVIC if a vCPU's ID is too big (relative to what hardware
supports) instead of rejecting vCPU creation
- Extend enable_ipiv module param support to SVM, by simply leaving
IsRunning clear in the vCPU's physical ID table entry
- Disable IPI virtualization, via enable_ipiv, if the CPU is affected
by erratum #1235, to allow (safely) enabling AVIC on such CPUs
- Request GA Log interrupts if and only if the target vCPU is
blocking, i.e. only if KVM needs a notification in order to wake
the vCPU
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to
the vCPU's CPUID model
- Accept any SNP policy that is accepted by the firmware with respect
to SMT and single-socket restrictions. An incompatible policy
doesn't put the kernel at risk in any way, so there's no reason for
KVM to care
- Drop a superfluous WBINVD (on all CPUs!) when destroying a VM and
use WBNOINVD instead of WBINVD when possible for SEV cache
maintenance
- When reclaiming memory from an SEV guest, only do cache flushes on
CPUs that have ever run a vCPU for the guest, i.e. don't flush the
caches for CPUs that can't possibly have cache lines with dirty,
encrypted data
Generic:
- Rework irqbypass to track/match producers and consumers via an
xarray instead of a linked list. Using a linked list leads to
O(n^2) insertion times, which is hugely problematic for use cases
that create large numbers of VMs. Such use cases typically don't
actually use irqbypass, but eliminating the pointless registration
is a future problem to solve as it likely requires new uAPI
- Track irqbypass's "token" as "struct eventfd_ctx *" instead of a
"void *", to avoid making a simple concept unnecessarily difficult
to understand
- Decouple device posted IRQs from VFIO device assignment, as binding
a VM to a VFIO group is not a requirement for enabling device
posted IRQs
- Clean up and document/comment the irqfd assignment code
- Disallow binding multiple irqfds to an eventfd with a priority
waiter, i.e. ensure an eventfd is bound to at most one irqfd
through the entire host, and add a selftest to verify eventfd:irqfd
bindings are globally unique
- Add a tracepoint for KVM_SET_MEMORY_ATTRIBUTES to help debug issues
related to private <=> shared memory conversions
- Drop guest_memfd's .getattr() implementation as the VFS layer will
call generic_fillattr() if inode_operations.getattr is NULL
- Fix issues with dirty ring harvesting where KVM doesn't bound the
processing of entries in any way, which allows userspace to keep
KVM in a tight loop indefinitely
- Kill off kvm_arch_{start,end}_assignment() and x86's associated
tracking, now that KVM no longer uses assigned_device_count as a
heuristic for either irqbypass usage or MDS mitigation
Selftests:
- Fix a comment typo
- Verify KVM is loaded when getting any KVM module param so that
attempting to run a selftest without kvm.ko loaded results in a
SKIP message about KVM not being loaded/enabled (versus some random
parameter not existing)
- Skip tests that hit EACCES when attempting to access a file, and
print a "Root required?" help message. In most cases, the test just
needs to be run with elevated permissions"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (340 commits)
Documentation: KVM: Use unordered list for pre-init VGIC registers
RISC-V: KVM: Avoid re-acquiring memslot in kvm_riscv_gstage_map()
RISC-V: KVM: Use find_vma_intersection() to search for intersecting VMAs
RISC-V: perf/kvm: Add reporting of interrupt events
RISC-V: KVM: Enable ring-based dirty memory tracking
RISC-V: KVM: Fix inclusion of Smnpm in the guest ISA bitmap
RISC-V: KVM: Delegate illegal instruction fault to VS mode
RISC-V: KVM: Pass VMID as parameter to kvm_riscv_hfence_xyz() APIs
RISC-V: KVM: Factor-out g-stage page table management
RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence
RISC-V: KVM: Introduce struct kvm_gstage_mapping
RISC-V: KVM: Factor-out MMU related declarations into separate headers
RISC-V: KVM: Use ncsr_xyz() in kvm_riscv_vcpu_trap_redirect()
RISC-V: KVM: Implement kvm_arch_flush_remote_tlbs_range()
RISC-V: KVM: Don't flush TLB when PTE is unchanged
RISC-V: KVM: Replace KVM_REQ_HFENCE_GVMA_VMID_ALL with KVM_REQ_TLB_FLUSH
RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize()
RISC-V: KVM: Drop the return value of kvm_riscv_vcpu_aia_init()
RISC-V: KVM: Check kvm_riscv_vcpu_alloc_vector_context() return value
KVM: arm64: selftests: Add FEAT_RAS EL2 registers to get-reg-list
...
Pull arm64 updates from Catalin Marinas:
"A quick summary: perf support for Branch Record Buffer Extensions
(BRBE), typical PMU hardware updates, small additions to MTE for
store-only tag checking and exposing non-address bits to signal
handlers, HAVE_LIVEPATCH enabled on arm64, VMAP_STACK forced on.
There is also a TLBI optimisation on hardware that does not require
break-before-make when changing the user PTEs between contiguous and
non-contiguous.
More details:
Perf and PMU updates:
- Add support for new (v3) Hisilicon SLLC and DDRC PMUs
- Add support for Arm-NI PMU integrations that share interrupts
between clock domains within a given instance
- Allow SPE to be configured with a lower sample period than the
minimum recommendation advertised by PMSIDR_EL1.Interval
- Add suppport for Arm's "Branch Record Buffer Extension" (BRBE)
- Adjust the perf watchdog period according to cpu frequency changes
- Minor driver fixes and cleanups
Hardware features:
- Support for MTE store-only checking (FEAT_MTE_STORE_ONLY)
- Support for reporting the non-address bits during a synchronous MTE
tag check fault (FEAT_MTE_TAGGED_FAR)
- Optimise the TLBI when folding/unfolding contiguous PTEs on
hardware with FEAT_BBM (break-before-make) level 2 and no TLB
conflict aborts
Software features:
- Enable HAVE_LIVEPATCH after implementing arch_stack_walk_reliable()
and using the text-poke API for late module relocations
- Force VMAP_STACK always on and change arm64_efi_rt_init() to use
arch_alloc_vmap_stack() in order to avoid KASAN false positives
ACPI:
- Improve SPCR handling and messaging on systems lacking an SPCR
table
Debug:
- Simplify the debug exception entry path
- Drop redundant DBG_MDSCR_* macros
Kselftests:
- Cleanups and improvements for SME, SVE and FPSIMD tests
Miscellaneous:
- Optimise loop to reduce redundant operations in contpte_ptep_get()
- Remove ISB when resetting POR_EL0 during signal handling
- Mark the kernel as tainted on SEA and SError panic
- Remove redundant gcs_free() call"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (93 commits)
arm64/gcs: task_gcs_el0_enable() should use passed task
arm64: Kconfig: Keep selects somewhat alphabetically ordered
arm64: signal: Remove ISB when resetting POR_EL0
kselftest/arm64: Handle attempts to disable SM on SME only systems
kselftest/arm64: Fix SVE write data generation for SME only systems
kselftest/arm64: Test SME on SME only systems in fp-ptrace
kselftest/arm64: Test FPSIMD format data writes via NT_ARM_SVE in fp-ptrace
kselftest/arm64: Allow sve-ptrace to run on SME only systems
arm64/mm: Drop redundant addr increment in set_huge_pte_at()
kselftest/arm4: Provide local defines for AT_HWCAP3
arm64: Mark kernel as tainted on SAE and SError panic
arm64/gcs: Don't call gcs_free() when releasing task_struct
drivers/perf: hisi: Support PMUs with no interrupt
drivers/perf: hisi: Relax the event number check of v2 PMUs
drivers/perf: hisi: Add support for HiSilicon SLLC v3 PMU driver
drivers/perf: hisi: Use ACPI driver_data to retrieve SLLC PMU information
drivers/perf: hisi: Add support for HiSilicon DDRC v3 PMU driver
drivers/perf: hisi: Simplify the probe process for each DDRC version
perf/arm-ni: Support sharing IRQs within an NI instance
perf/arm-ni: Consolidate CPU affinity handling
...
KVM/arm64 changes for 6.17, round #1 - Host driver for GICv5, the next generation interrupt controller for arm64, including support for interrupt routing, MSIs, interrupt translation and wired interrupts. - Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on GICv5 hardware, leveraging the legacy VGIC interface. - Userspace control of the 'nASSGIcap' GICv3 feature, allowing userspace to disable support for SGIs w/o an active state on hardware that previously advertised it unconditionally. - Map supporting endpoints with cacheable memory attributes on systems with FEAT_S2FWB and DIC where KVM no longer needs to perform cache maintenance on the address range. - Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the guest hypervisor to inject external aborts into an L2 VM and take traps of masked external aborts to the hypervisor. - Convert more system register sanitization to the config-driven implementation. - Fixes to the visibility of EL2 registers, namely making VGICv3 system registers accessible through the VGIC device instead of the ONE_REG vCPU ioctls. - Various cleanups and minor fixes.
KVM selftests changes for 6.17 - Fix a comment typo. - Verify KVM is loaded when getting any KVM module param so that attempting to run a selftest without kvm.ko loaded results in a SKIP message about KVM not being loaded/enabled, versus some random parameter not existing. - SKIP tests that hit EACCES when attempting to access a file, with a "Root required?" help message. In most cases, the test just needs to be run with elevated permissions.
KVM x86 misc changes for 6.17 - Prevert the host's DEBUGCTL.FREEZE_IN_SMM (Intel only) when running the guest. Failure to honor FREEZE_IN_SMM can bleed host state into the guest. - Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter (Intel only) to prevent L1 from running L2 with features that KVM doesn't support, e.g. BTF. - Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to the vCPU's CPUID model. - Rework the MSR interception code so that the SVM and VMX APIs are more or less identical. - Recalculate all MSR intercepts from the "source" on MSR filter changes, and drop the dedicated "shadow" bitmaps (and their awful "max" size defines). - WARN and reject loading kvm-amd.ko instead of panicking the kernel if the nested SVM MSRPM offsets tracker can't handle an MSR. - Advertise support for LKGS (Load Kernel GS base), a new instruction that's loosely related to FRED, but is supported and enumerated independently. - Fix a user-triggerable WARN that syzkaller found by stuffing INIT_RECEIVED, a.k.a. WFS, and then putting the vCPU into VMX Root Mode (post-VMXON). Use the same approach KVM uses for dealing with "impossible" emulation when running a !URG guest, and simply wait until KVM_RUN to detect that the vCPU has architecturally impossible state. - Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling interception of APERF/MPERF reads, so that a "properly" configured VM can "virtualize" APERF/MPERF (with many caveats). - Reject KVM_SET_TSC_KHZ if vCPUs have been created, as changing the "default" frequency is unsupported for VMs with a "secure" TSC, and there's no known use case for changing the default frequency for other VM types.
KVM IRQ changes for 6.17 - Rework irqbypass to track/match producers and consumers via an xarray instead of a linked list. Using a linked list leads to O(n^2) insertion times, which is hugely problematic for use cases that create large numbers of VMs. Such use cases typically don't actually use irqbypass, but eliminating the pointless registration is a future problem to solve as it likely requires new uAPI. - Track irqbypass's "token" as "struct eventfd_ctx *" instead of a "void *", to avoid making a simple concept unnecessarily difficult to understand. - Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O APIC, PIC, and PIT emulation at compile time. - Drop x86's irq_comm.c, and move a pile of IRQ related code into irq.c. - Fix a variety of flaws and bugs in the AVIC device posted IRQ code. - Inhibited AVIC if a vCPU's ID is too big (relative to what hardware supports) instead of rejecting vCPU creation. - Extend enable_ipiv module param support to SVM, by simply leaving IsRunning clear in the vCPU's physical ID table entry. - Disable IPI virtualization, via enable_ipiv, if the CPU is affected by erratum #1235, to allow (safely) enabling AVIC on such CPUs. - Dedup x86's device posted IRQ code, as the vast majority of functionality can be shared verbatime between SVM and VMX. - Harden the device posted IRQ code against bugs and runtime errors. - Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups O(1) instead of O(n). - Generate GA Log interrupts if and only if the target vCPU is blocking, i.e. only if KVM needs a notification in order to wake the vCPU. - Decouple device posted IRQs from VFIO device assignment, as binding a VM to a VFIO group is not a requirement for enabling device posted IRQs. - Clean up and document/comment the irqfd assignment code. - Disallow binding multiple irqfds to an eventfd with a priority waiter, i.e. ensure an eventfd is bound to at most one irqfd through the entire host, and add a selftest to verify eventfd:irqfd bindings are globally unique.