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2024-07-20Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "ARM: - Initial infrastructure for shadow stage-2 MMUs, as part of nested virtualization enablement - Support for userspace changes to the guest CTR_EL0 value, enabling (in part) migration of VMs between heterogenous hardware - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of the protocol - FPSIMD/SVE support for nested, including merged trap configuration and exception routing - New command-line parameter to control the WFx trap behavior under KVM - Introduce kCFI hardening in the EL2 hypervisor - Fixes + cleanups for handling presence/absence of FEAT_TCRX - Miscellaneous fixes + documentation updates LoongArch: - Add paravirt steal time support - Add support for KVM_DIRTY_LOG_INITIALLY_SET - Add perf kvm-stat support for loongarch RISC-V: - Redirect AMO load/store access fault traps to guest - perf kvm stat support - Use guest files for IMSIC virtualization, when available s390: - Assortment of tiny fixes which are not time critical x86: - Fixes for Xen emulation - Add a global struct to consolidate tracking of host values, e.g. EFER - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC bus frequency, because TDX - Print the name of the APICv/AVIC inhibits in the relevant tracepoint - Clean up KVM's handling of vendor specific emulation to consistently act on "compatible with Intel/AMD", versus checking for a specific vendor - Drop MTRR virtualization, and instead always honor guest PAT on CPUs that support self-snoop - Update to the newfangled Intel CPU FMS infrastructure - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads '0' and writes from userspace are ignored - Misc cleanups x86 - MMU: - Small cleanups, renames and refactoring extracted from the upcoming Intel TDX support - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't hold leafs SPTEs - Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager page splitting, to avoid stalling vCPUs when splitting huge pages - Bug the VM instead of simply warning if KVM tries to split a SPTE that is non-present or not-huge. KVM is guaranteed to end up in a broken state because the callers fully expect a valid SPTE, it's all but dangerous to let more MMU changes happen afterwards x86 - AMD: - Make per-CPU save_area allocations NUMA-aware - Force sev_es_host_save_area() to be inlined to avoid calling into an instrumentable function from noinstr code - Base support for running SEV-SNP guests. API-wise, this includes a new KVM_X86_SNP_VM type, encrypting/measure the initial image into guest memory, and finalizing it before launching it. Internally, there are some gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges This includes basic support for attestation guest requests, enough to say that KVM supports the GHCB 2.0 specification There is no support yet for loading into the firmware those signing keys to be used for attestation requests, and therefore no need yet for the host to provide certificate data for those keys. To support fetching certificate data from userspace, a new KVM exit type will be needed to handle fetching the certificate from userspace. An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS exit type to handle this was introduced in v1 of this patchset, but is still being discussed by community, so for now this patchset only implements a stub version of SNP Extended Guest Requests that does not provide certificate data x86 - Intel: - Remove an unnecessary EPT TLB flush when enabling hardware - Fix a series of bugs that cause KVM to fail to detect nested pending posted interrupts as valid wake eents for a vCPU executing HLT in L2 (with HLT-exiting disable by L1) - KVM: x86: Suppress MMIO that is triggered during task switch emulation Explicitly suppress userspace emulated MMIO exits that are triggered when emulating a task switch as KVM doesn't support userspace MMIO during complex (multi-step) emulation Silently ignoring the exit request can result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace for some other reason prior to purging mmio_needed See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write exits if emulator detects exception") for more details on KVM's limitations with respect to emulated MMIO during complex emulator flows Generic: - Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE, because the special casing needed by these pages is not due to just unmovability (and in fact they are only unmovable because the CPU cannot access them) - New ioctl to populate the KVM page tables in advance, which is useful to mitigate KVM page faults during guest boot or after live migration. The code will also be used by TDX, but (probably) not through the ioctl - Enable halt poll shrinking by default, as Intel found it to be a clear win - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out() - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout Selftests: - Remove dead code in the memslot modification stress test - Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs - Print the guest pseudo-RNG seed only when it changes, to avoid spamming the log for tests that create lots of VMs - Make the PMU counters test less flaky when counting LLC cache misses by doing CLFLUSH{OPT} in every loop iteration" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) crypto: ccp: Add the SNP_VLEK_LOAD command KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops KVM: x86: Replace static_call_cond() with static_call() KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event x86/sev: Move sev_guest.h into common SEV header KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event KVM: x86: Suppress MMIO that is triggered during task switch emulation KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory KVM: Document KVM_PRE_FAULT_MEMORY ioctl mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE perf kvm: Add kvm-stat for loongarch64 LoongArch: KVM: Add PV steal time support in guest side ...
2024-07-14Merge branch kvm-arm64/nv-tcr2 into kvmarm/nextOliver Upton
* kvm-arm64/nv-tcr2: : Fixes to the handling of TCR_EL1, courtesy of Marc Zyngier : : Series addresses a couple gaps that are present in KVM (from cover : letter): : : - VM configuration: HCRX_EL2.TCR2En is forced to 1, and we blindly : save/restore stuff. : : - trap bit description and routing: none, obviously, since we make a : point in not trapping. KVM: arm64: Honor trap routing for TCR2_EL1 KVM: arm64: Make PIR{,E0}_EL1 save/restore conditional on FEAT_TCRX KVM: arm64: Make TCR2_EL1 save/restore dependent on the VM features KVM: arm64: Get rid of HCRX_GUEST_FLAGS KVM: arm64: Correctly honor the presence of FEAT_TCRX Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-14Merge branch kvm-arm64/nv-sve into kvmarm/nextOliver Upton
* kvm-arm64/nv-sve: : CPTR_EL2, FPSIMD/SVE support for nested : : This series brings support for honoring the guest hypervisor's CPTR_EL2 : trap configuration when running a nested guest, along with support for : FPSIMD/SVE usage at L1 and L2. KVM: arm64: Allow the use of SVE+NV KVM: arm64: nv: Add additional trap setup for CPTR_EL2 KVM: arm64: nv: Add trap description for CPTR_EL2 KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2 KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap KVM: arm64: nv: Handle CPACR_EL1 traps KVM: arm64: Spin off helper for programming CPTR traps KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state KVM: arm64: nv: Use guest hypervisor's max VL when running nested guest KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context KVM: arm64: nv: Load guest hyp's ZCR into EL1 state KVM: arm64: nv: Handle ZCR_EL2 traps KVM: arm64: nv: Forward SVE traps to guest hypervisor KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-14Merge branch kvm-arm64/el2-kcfi into kvmarm/nextOliver Upton
* kvm-arm64/el2-kcfi: : kCFI support in the EL2 hypervisor, courtesy of Pierre-Clément Tosi : : Enable the usage fo CONFIG_CFI_CLANG (kCFI) for hardening indirect : branches in the EL2 hypervisor. Unlike kernel support for the feature, : CFI failures at EL2 are always fatal. KVM: arm64: nVHE: Support CONFIG_CFI_CLANG at EL2 KVM: arm64: Introduce print_nvhe_hyp_panic helper arm64: Introduce esr_brk_comment, esr_is_cfi_brk KVM: arm64: VHE: Mark __hyp_call_panic __noreturn KVM: arm64: nVHE: gen-hyprel: Skip R_AARCH64_ABS32 KVM: arm64: nVHE: Simplify invalid_host_el2_vect KVM: arm64: Fix __pkvm_init_switch_pgd call ABI KVM: arm64: Fix clobbered ELR in sync abort/SError Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-07-04KVM: arm64: Replace custom macros with fields from ID_AA64PFR0_EL1Anshuman Khandual
This replaces custom macros usage (i.e ID_AA64PFR0_EL1_ELx_64BIT_ONLY and ID_AA64PFR0_EL1_ELx_32BIT_64BIT) and instead directly uses register fields from ID_AA64PFR0_EL1 sysreg definition. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.linux.dev Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20240613102710.3295108-2-anshuman.khandual@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-06-27KVM: arm64: Make PIR{,E0}_EL1 save/restore conditional on FEAT_TCRXMarc Zyngier
As per the architecture, if FEAT_S1PIE is implemented, then FEAT_TCRX must be implemented as well. Take advantage of this to avoid checking for S1PIE when TCRX isn't implemented. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240625130042.259175-6-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-27KVM: arm64: Make TCR2_EL1 save/restore dependent on the VM featuresMarc Zyngier
As for other registers, save/restore of TCR2_EL1 should be gated on the feature being actually present. In the case of a nVHE hypervisor, it is perfectly fine to leave the host value in the register, as HCRX_EL2.TCREn==0 imposes that TCR2_EL1 is treated as 0. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240625130042.259175-4-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: nv: Load guest FP state for ZCR_EL2 trapOliver Upton
Round out the ZCR_EL2 gymnastics by loading SVE state in the fast path when the guest hypervisor tries to access SVE state. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-11-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: nv: Use guest hypervisor's max VL when running nested guestOliver Upton
The max VL for nested guests is additionally constrained by the max VL selected by the guest hypervisor. Use that instead of KVM's max VL when running a nested guest. Note that the guest hypervisor's ZCR_EL2 is sanitised against the VM's max VL at the time of access, so there's no additional handling required at the time of use. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-7-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: nv: Load guest hyp's ZCR into EL1 stateOliver Upton
Load the guest hypervisor's ZCR_EL2 into the corresponding EL1 register when restoring SVE state, as ZCR_EL2 affects the VL in the hypervisor context. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-5-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: nv: Forward SVE traps to guest hypervisorOliver Upton
Similar to FPSIMD traps, don't load SVE state if the guest hypervisor has SVE traps enabled and forward the trap instead. Note that ZCR_EL2 will require some special handling, as it takes a sysreg trap to EL2 when HCR_EL2.NV = 1. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-3-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisorJintack Lim
Give precedence to the guest hypervisor's trap configuration when routing an FP/ASIMD trap taken to EL2. Take advantage of the infrastructure for translating CPTR_EL2 into the VHE (i.e. EL1) format and base the trap decision solely on the VHE view of the register. The in-memory value of CPTR_EL2 will always be up to date for the guest hypervisor (more on that later), so just read it directly from memory. Bury all of this behind a macro keyed off of the CPTR bitfield in anticipation of supporting other traps (e.g. SVE). [maz: account for HCR_EL2.E2H when testing for TFP/FPEN, with all the hard work actually being done by Chase Conklin] [ oliver: translate nVHE->VHE format for testing traps; macro for reuse in other CPTR_EL2.xEN fields ] Signed-off-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240620164653.1130714-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: Fix clobbered ELR in sync abort/SErrorPierre-Clément Tosi
When the hypervisor receives a SError or synchronous exception (EL2h) while running with the __kvm_hyp_vector and if ELR_EL2 doesn't point to an extable entry, it panics indirectly by overwriting ELR with the address of a panic handler in order for the asm routine it returns to to ERET into the handler. However, this clobbers ELR_EL2 for the handler itself. As a result, hyp_panic(), when retrieving what it believes to be the PC where the exception happened, actually ends up reading the address of the panic handler that called it! This results in an erroneous and confusing panic message where the source of any synchronous exception (e.g. BUG() or kCFI) appears to be __guest_exit_panic, making it hard to locate the actual BRK instruction. Therefore, store the original ELR_EL2 in the per-CPU kvm_hyp_ctxt and point the sysreg to a routine that first restores it to its previous value before running __guest_exit_panic. Fixes: 7db21530479f ("KVM: arm64: Restore hyp when panicking in guest context") Signed-off-by: Pierre-Clément Tosi <ptosi@google.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20240610063244.2828978-2-ptosi@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-14KVM: arm64: Update the identification range for the FF-A smcsSebastian Ene
The FF-A spec 1.2 reserves the following ranges for identifying FF-A calls: 0x84000060-0x840000FF: FF-A 32-bit calls 0xC4000060-0xC40000FF: FF-A 64-bit calls. Use the range identification according to the spec and allow calls that are currently out of the range(eg. FFA_MSG_SEND_DIRECT_REQ2) to be identified correctly. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Sebastian Ene <sebastianene@google.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240613132035.1070360-4-sebastianene@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-04KVM: arm64: Consolidate initializing the host data's fpsimd_state/sve in pKVMFuad Tabba
Now that we have introduced finalize_init_hyp_mode(), lets consolidate the initializing of the host_data fpsimd_state and sve state. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20240603122852.3923848-8-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Eagerly restore host fpsimd/sve state in pKVMFuad Tabba
When running in protected mode we don't want to leak protected guest state to the host, including whether a guest has used fpsimd/sve. Therefore, eagerly restore the host state on guest exit when running in protected mode, which happens only if the guest has used fpsimd/sve. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-7-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Specialize handling of host fpsimd state on trapFuad Tabba
In subsequent patches, n/vhe will diverge on saving the host fpsimd/sve state when taking a guest fpsimd/sve trap. Add a specialized helper to handle it. No functional change intended. Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-5-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Abstract set/clear of CPTR_EL2 bits behind helperFuad Tabba
The same traps controlled by CPTR_EL2 or CPACR_EL1 need to be toggled in different parts of the code, but the exact bits and their polarity differ between these two formats and the mode (vhe/nvhe/hvhe). To reduce the amount of duplicated code and the chance of getting the wrong bit/polarity or missing a field, abstract the set/clear of CPTR_EL2 bits behind a helper. Since (h)VHE is the way of the future, use the CPACR_EL1 format, which is a subset of the VHE CPTR_EL2, as a reference. No functional change intended. Suggested-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-4-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Fix prototype for __sve_save_state/__sve_restore_stateFuad Tabba
Since the prototypes for __sve_save_state/__sve_restore_state at hyp were added, the underlying macro has acquired a third parameter for saving/restoring ffr. Fix the prototypes to account for the third parameter, and restore the ffr for the guest since it is saved. Suggested-by: Mark Brown <broonie@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20240603122852.3923848-3-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03Merge branch kvm-arm64/pkvm-6.10 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-6.10: (25 commits) : . : At last, a bunch of pKVM patches, courtesy of Fuad Tabba. : From the cover letter: : : "This series is a bit of a bombay-mix of patches we've been : carrying. There's no one overarching theme, but they do improve : the code by fixing existing bugs in pKVM, refactoring code to : make it more readable and easier to re-use for pKVM, or adding : functionality to the existing pKVM code upstream." : . KVM: arm64: Force injection of a data abort on NISV MMIO exit KVM: arm64: Restrict supported capabilities for protected VMs KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap() KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst KVM: arm64: Rename firmware pseudo-register documentation file KVM: arm64: Reformat/beautify PTP hypercall documentation KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit KVM: arm64: Introduce and use predicates that check for protected VMs KVM: arm64: Add is_pkvm_initialized() helper KVM: arm64: Simplify vgic-v3 hypercalls KVM: arm64: Move setting the page as dirty out of the critical section KVM: arm64: Change kvm_handle_mmio_return() return polarity KVM: arm64: Fix comment for __pkvm_vcpu_init_traps() KVM: arm64: Prevent kmemleak from accessing .hyp.data KVM: arm64: Do not map the host fpsimd state to hyp in pKVM KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE KVM: arm64: Support TLB invalidation in guest context KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE KVM: arm64: Check for PTE validity when checking for executable/cacheable KVM: arm64: Avoid BUG-ing from the host abort path ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03Merge branch kvm-arm64/nv-eret-pauth into kvmarm-master/nextMarc Zyngier
* kvm-arm64/nv-eret-pauth: : . : Add NV support for the ERETAA/ERETAB instructions. From the cover letter: : : "Although the current upstream NV support has *some* support for : correctly emulating ERET, that support is only partial as it doesn't : support the ERETAA and ERETAB variants. : : Supporting these instructions was cast aside for a long time as it : involves implementing some form of PAuth emulation, something I wasn't : overly keen on. But I have reached a point where enough of the : infrastructure is there that it actually makes sense. So here it is!" : . KVM: arm64: nv: Work around lack of pauth support in old toolchains KVM: arm64: Drop trapping of PAuth instructions/keys KVM: arm64: nv: Advertise support for PAuth KVM: arm64: nv: Handle ERETA[AB] instructions KVM: arm64: nv: Add emulation for ERETAx instructions KVM: arm64: nv: Add kvm_has_pauth() helper KVM: arm64: nv: Reinject PAC exceptions caused by HCR_EL2.API==0 KVM: arm64: nv: Handle HCR_EL2.{API,APK} independently KVM: arm64: nv: Honor HFGITR_EL2.ERET being set KVM: arm64: nv: Fast-track 'InHost' exception returns KVM: arm64: nv: Add trap forwarding for ERET and SMC KVM: arm64: nv: Configure HCR_EL2 for FEAT_NV2 KVM: arm64: nv: Drop VCPU_HYP_CONTEXT flag KVM: arm64: Constraint PAuth support to consistent implementations KVM: arm64: Add helpers for ESR_ELx_ERET_ISS_ERET* KVM: arm64: Harden __ctxt_sys_reg() against out-of-range values Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Introduce and use predicates that check for protected VMsFuad Tabba
In order to determine whether or not a VM or vcpu are protected, introduce helpers to query this state. While at it, use the vcpu helper to check vcpus protected state instead of the kvm one. Co-authored-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-19-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Refactor checks for FP state ownershipFuad Tabba
To avoid direct comparison against the fp_owner enum, add a new function that performs the check, host_owns_fp_regs(), to complement the existing guest_owns_fp_regs(). To check for fpsimd state ownership, use the helpers instead of directly using the enums. No functional change intended. Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-4-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Move guest_owns_fp_regs() to increase its scopeFuad Tabba
guest_owns_fp_regs() will be used to check fpsimd state ownership across kvm/arm64. Therefore, move it to kvm_host.h to widen its scope. Moreover, the host state is not per-vcpu anymore, the vcpu parameter isn't used, so remove it as well. No functional change intended. Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Mark Brown <broonie@kernel.org> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-3-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01KVM: arm64: Initialize the kvm host data's fpsimd_state pointer in pKVMFuad Tabba
Since the host_fpsimd_state has been removed from kvm_vcpu_arch, it isn't pointing to the hyp's version of the host fp_regs in protected mode. Initialize the host_data fpsimd_state point to the host_data's context fp_regs on pKVM initialization. Fixes: 51e09b5572d6 ("KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch") Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-2-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-20KVM: arm64: Drop trapping of PAuth instructions/keysMarc Zyngier
We currently insist on disabling PAuth on vcpu_load(), and get to enable it on first guest use of an instruction or a key (ignoring the NV case for now). It isn't clear at all what this is trying to achieve: guests tend to use PAuth when available, and nothing forces you to expose it to the guest if you don't want to. This also isn't totally free: we take a full GPR save/restore between host and guest, only to write ten 64bit registers. The "value proposition" escapes me. So let's forget this stuff and enable PAuth eagerly if exposed to the guest. This results in much simpler code. Performance wise, that's not bad either (tested on M2 Pro running a fully automated Debian installer as the workload): - On a non-NV guest, I can see reduction of 0.24% in the number of cycles (measured with perf over 10 consecutive runs) - On a NV guest (L2), I see a 2% reduction in wall-clock time (measured with 'time', as M2 doesn't have a PMUv3 and NV doesn't support it either) So overall, a much reduced complexity and a (small) performance improvement. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240419102935.1935571-16-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-20KVM: arm64: nv: Handle HCR_EL2.{API,APK} independentlyMarc Zyngier
Although KVM couples API and APK for simplicity, the architecture makes no such requirement, and the two can be independently set or cleared. Check for which of the two possible reasons we have trapped here, and if the corresponding L1 control bit isn't set, delegate the handling for forwarding. Otherwise, set this exact bit in HCR_EL2 and resume the guest. Of course, in the non-NV case, we keep setting both bits and be done with it. Note that the entry core already saves/restores the keys should any of the two control bits be set. This results in a bit of rework, and the removal of the (trivial) vcpu_ptrauth_enable() helper. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240419102935.1935571-10-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-20KVM: arm64: nv: Configure HCR_EL2 for FEAT_NV2Marc Zyngier
Add the HCR_EL2 configuration for FEAT_NV2, adding the required bits for running a guest hypervisor, and overall merging the allowed bits provided by the guest. This heavily replies on unavaliable features being sanitised when the HCR_EL2 shadow register is accessed, and only a couple of bits must be explicitly disabled. Non-NV guests are completely unaffected by any of this. Reviewed-by: Joey Gouly <joey.gouly@arm.com> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240419102935.1935571-6-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Exclude FP ownership from kvm_vcpu_archMarc Zyngier
In retrospect, it is fairly obvious that the FP state ownership is only meaningful for a given CPU, and that locating this information in the vcpu was just a mistake. Move the ownership tracking into the host data structure, and rename it from fp_state to fp_owner, which is a better description (name suggested by Mark Brown). Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_archMarc Zyngier
As the name of the field indicates, host_fpsimd_state is strictly a host piece of data, and we reset this pointer on each PID change. So let's move it where it belongs, and set it at load-time. Although this is slightly more often, it is a well defined life-cycle which matches other pieces of data. Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Exclude mdcr_el2_host from kvm_vcpu_archMarc Zyngier
As for the rest of the host debug state, the host copy of mdcr_el2 has little to do in the vcpu, and is better placed in the host_data structure. Reviewed-by : Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Exclude host_debug_data from vcpu_archMarc Zyngier
Keeping host_debug_state on a per-vcpu basis is completely pointless. The lifetime of this data is only that of the inner run-loop, which means it is never accessed outside of the core EL2 code. Move the structure into kvm_host_data, and save over 500 bytes per vcpu. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-04-12KVM: arm64: Add accessor for per-CPU stateMarc Zyngier
In order to facilitate the introduction of new per-CPU state, add a new host_data_ptr() helped that hides some of the per-CPU verbosity, and make it easier to move that state around in the future. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-02-19KVM: arm64: Make FEAT_MOPS UNDEF if not advertised to the guestMarc Zyngier
We unconditionally enable FEAT_MOPS, which is obviously wrong. So let's only do that when it is advertised to the guest. Which means we need to rely on a per-vcpu HCRX_EL2 shadow register. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20240214131827.2856277-25-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: Make PIR{,E0}_EL1 UNDEF if S1PIE is not advertised to the guestMarc Zyngier
As part of the ongoing effort to honor the guest configuration, add the necessary checks to make PIR_EL1 and co UNDEF if not advertised to the guest, and avoid context switching them. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20240214131827.2856277-23-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: Streamline save/restore of HFG[RW]TR_EL2Marc Zyngier
The way we save/restore HFG[RW]TR_EL2 can now be simplified, and the Ampere erratum hack is the only thing that still stands out. Reviewed-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240214131827.2856277-21-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: Move existing feature disabling over to FGU infrastructureMarc Zyngier
We already trap a bunch of existing features for the purpose of disabling them (MAIR2, POR, ACCDATA, SME...). Let's move them over to our brand new FGU infrastructure. Reviewed-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240214131827.2856277-20-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-19KVM: arm64: Propagate and handle Fine-Grained UNDEF bitsMarc Zyngier
In order to correctly honor our FGU bits, they must be converted into a set of FGT bits. They get merged as part of the existing FGT setting. Similarly, the UNDEF injection phase takes place when handling the trap. This results in a bit of rework in the FGT macros in order to help with the code generation, as burying per-CPU accesses in macros results in a lot of expansion, not to mention the vcpu->kvm access on nvhe (kern_hyp_va() is not optimisation-friendly). Reviewed-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240214131827.2856277-19-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-01-17Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "Generic: - Use memdup_array_user() to harden against overflow. - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures. - Clean up Kconfigs that all KVM architectures were selecting - New functionality around "guest_memfd", a new userspace API that creates an anonymous file and returns a file descriptor that refers to it. guest_memfd files are bound to their owning virtual machine, cannot be mapped, read, or written by userspace, and cannot be resized. guest_memfd files do however support PUNCH_HOLE, which can be used to switch a memory area between guest_memfd and regular anonymous memory. - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify per-page attributes for a given page of guest memory; right now the only attribute is whether the guest expects to access memory via guest_memfd or not, which in Confidential SVMs backed by SEV-SNP, TDX or ARM64 pKVM is checked by firmware or hypervisor that guarantees confidentiality (AMD PSP, Intel TDX module, or EL2 in the case of pKVM). x86: - Support for "software-protected VMs" that can use the new guest_memfd and page attributes infrastructure. This is mostly useful for testing, since there is no pKVM-like infrastructure to provide a meaningfully reduced TCB. - Fix a relatively benign off-by-one error when splitting huge pages during CLEAR_DIRTY_LOG. - Fix a bug where KVM could incorrectly test-and-clear dirty bits in non-leaf TDP MMU SPTEs if a racing thread replaces a huge SPTE with a non-huge SPTE. - Use more generic lockdep assertions in paths that don't actually care about whether the caller is a reader or a writer. - let Xen guests opt out of having PV clock reported as "based on a stable TSC", because some of them don't expect the "TSC stable" bit (added to the pvclock ABI by KVM, but never set by Xen) to be set. - Revert a bogus, made-up nested SVM consistency check for TLB_CONTROL. - Advertise flush-by-ASID support for nSVM unconditionally, as KVM always flushes on nested transitions, i.e. always satisfies flush requests. This allows running bleeding edge versions of VMware Workstation on top of KVM. - Sanity check that the CPU supports flush-by-ASID when enabling SEV support. - On AMD machines with vNMI, always rely on hardware instead of intercepting IRET in some cases to detect unmasking of NMIs - Support for virtualizing Linear Address Masking (LAM) - Fix a variety of vPMU bugs where KVM fail to stop/reset counters and other state prior to refreshing the vPMU model. - Fix a double-overflow PMU bug by tracking emulated counter events using a dedicated field instead of snapshotting the "previous" counter. If the hardware PMC count triggers overflow that is recognized in the same VM-Exit that KVM manually bumps an event count, KVM would pend PMIs for both the hardware-triggered overflow and for KVM-triggered overflow. - Turn off KVM_WERROR by default for all configs so that it's not inadvertantly enabled by non-KVM developers, which can be problematic for subsystems that require no regressions for W=1 builds. - Advertise all of the host-supported CPUID bits that enumerate IA32_SPEC_CTRL "features". - Don't force a masterclock update when a vCPU synchronizes to the current TSC generation, as updating the masterclock can cause kvmclock's time to "jump" unexpectedly, e.g. when userspace hotplugs a pre-created vCPU. - Use RIP-relative address to read kvm_rebooting in the VM-Enter fault paths, partly as a super minor optimization, but mostly to make KVM play nice with position independent executable builds. - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on CONFIG_HYPERV as a minor optimization, and to self-document the code. - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV "emulation" at build time. ARM64: - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base granule sizes. Branch shared with the arm64 tree. - Large Fine-Grained Trap rework, bringing some sanity to the feature, although there is more to come. This comes with a prefix branch shared with the arm64 tree. - Some additional Nested Virtualization groundwork, mostly introducing the NV2 VNCR support and retargetting the NV support to that version of the architecture. - A small set of vgic fixes and associated cleanups. Loongarch: - Optimization for memslot hugepage checking - Cleanup and fix some HW/SW timer issues - Add LSX/LASX (128bit/256bit SIMD) support RISC-V: - KVM_GET_REG_LIST improvement for vector registers - Generate ISA extension reg_list using macros in get-reg-list selftest - Support for reporting steal time along with selftest s390: - Bugfixes Selftests: - Fix an annoying goof where the NX hugepage test prints out garbage instead of the magic token needed to run the test. - Fix build errors when a header is delete/moved due to a missing flag in the Makefile. - Detect if KVM bugged/killed a selftest's VM and print out a helpful message instead of complaining that a random ioctl() failed. - Annotate the guest printf/assert helpers with __printf(), and fix the various bugs that were lurking due to lack of said annotation" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (185 commits) x86/kvm: Do not try to disable kvmclock if it was not enabled KVM: x86: add missing "depends on KVM" KVM: fix direction of dependency on MMU notifiers KVM: introduce CONFIG_KVM_COMMON KVM: arm64: Add missing memory barriers when switching to pKVM's hyp pgd KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache RISC-V: KVM: selftests: Add get-reg-list test for STA registers RISC-V: KVM: selftests: Add steal_time test support RISC-V: KVM: selftests: Add guest_sbi_probe_extension RISC-V: KVM: selftests: Move sbi_ecall to processor.c RISC-V: KVM: Implement SBI STA extension RISC-V: KVM: Add support for SBI STA registers RISC-V: KVM: Add support for SBI extension registers RISC-V: KVM: Add SBI STA info to vcpu_arch RISC-V: KVM: Add steal-update vcpu request RISC-V: KVM: Add SBI STA extension skeleton RISC-V: paravirt: Implement steal-time support RISC-V: Add SBI STA extension definitions RISC-V: paravirt: Add skeleton for pv-time support RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr() ...
2024-01-08mm, treewide: introduce NR_PAGE_ORDERSKirill A. Shutemov
NR_PAGE_ORDERS defines the number of page orders supported by the page allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total. NR_PAGE_ORDERS assists in defining arrays of page orders and allows for more natural iteration over them. [kirill.shutemov@linux.intel.com: fixup for kerneldoc warning] Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-18Merge branch kvm-arm64/fgt-rework into kvmarm-master/nextMarc Zyngier
* kvm-arm64/fgt-rework: (30 commits) : . : Fine Grain Trapping update, courtesy of Fuad Tabba. : : From the cover letter: : : "This patch series has fixes, updates, and code for validating : fine grain trap register masks, as well as some fixes to feature : trapping in pKVM. : : New fine grain trap (FGT) bits have been defined in the latest : Arm Architecture System Registers xml specification (DDI0601 and : DDI0602 2023-09) [1], so the code is updated to reflect them. : Moreover, some of the already-defined masks overlap with RES0, : which this series fixes. : : It also adds FGT register masks that weren't defined earlier, : handling of HAFGRTR_EL2 in nested virt, as well as build time : validation that the bits of the various masks are all accounted : for and without overlap." : : This branch also drags the arm64/for-next/sysregs branch, : which is a dependency on this work. : . KVM: arm64: Trap external trace for protected VMs KVM: arm64: Mark PAuth as a restricted feature for protected VMs KVM: arm64: Fix which features are marked as allowed for protected VMs KVM: arm64: Macros for setting/clearing FGT bits KVM: arm64: Define FGT nMASK bits relative to other fields KVM: arm64: Use generated FGT RES0 bits instead of specifying them KVM: arm64: Add build validation for FGT trap mask values KVM: arm64: Update and fix FGT register masks KVM: arm64: Handle HAFGRTR_EL2 trapping in nested virt KVM: arm64: Add bit masks for HAFGRTR_EL2 KVM: arm64: Add missing HFGITR_EL2 FGT entries to nested virt KVM: arm64: Add missing HFGxTR_EL2 FGT entries to nested virt KVM: arm64: Explicitly trap unsupported HFGxTR_EL2 features arm64/sysreg: Add missing system instruction definitions for FGT arm64/sysreg: Add missing system register definitions for FGT arm64/sysreg: Add missing ExtTrcBuff field definition to ID_AA64DFR0_EL1 arm64/sysreg: Add missing Pauth_LR field definitions to ID_AA64ISAR1_EL1 arm64/sysreg: Add new system registers for GCS arm64/sysreg: Add definition for FPMR arm64/sysreg: Update HCRX_EL2 definition for DDI0601 2023-09 ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2023-12-18KVM: arm64: Mark PAuth as a restricted feature for protected VMsFuad Tabba
Protected VMs will only support basic PAuth (FEAT_PAuth). Mark it as restricted to ensure that later versions aren't supported for protected guests. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-17-tabba@google.com
2023-12-18KVM: arm64: Fix which features are marked as allowed for protected VMsFuad Tabba
Cache maintenance operations are not trapped for protected VMs, and shouldn't be. Mark them as allowed. Moreover, features advertised by ID_AA64PFR2 and ID_AA64MMFR3 are (already) not allowed, mark them as such. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-16-tabba@google.com
2023-12-18KVM: arm64: Macros for setting/clearing FGT bitsFuad Tabba
There's a lot of boilerplate code for setting and clearing FGT bits when activating guest traps. Refactor it into macros. These macros will also be used in future patch series. No functional change intended. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-15-tabba@google.com
2023-12-18KVM: arm64: Add build validation for FGT trap mask valuesFuad Tabba
These checks help ensure that all the bits are accounted for, that there hasn't been a transcribing error from the spec nor from the generated mask values, which will be used in subsequent patches. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-12-tabba@google.com
2023-12-18KVM: arm64: Handle HAFGRTR_EL2 trapping in nested virtFuad Tabba
Add the encodings to fine grain trapping fields for HAFGRTR_EL2 and add the associated handling code in nested virt. Based on DDI0601 2023-09. Add the missing field definitions as well, both to generate the correct RES0 mask and to be able to toggle their FGT bits. Also add the code for handling FGT trapping, reading of the register, to nested virt. Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-10-tabba@google.com
2023-12-18KVM: arm64: Explicitly trap unsupported HFGxTR_EL2 featuresFuad Tabba
Do not rely on the value of __HFGRTR_EL2_nMASK to trap unsupported features, since the nMASK can (and will) change as new traps are added and as its value is updated. Instead, explicitly specify the trap bits. Suggested-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231214100158.2305400-6-tabba@google.com
2023-11-30KVM: arm64: Use helpers to classify exception types reported via ESRArd Biesheuvel
Currently, we rely on the fact that exceptions can be trivially classified by applying a mask/value pair to the syndrome value reported via the ESR register, but this will no longer be true once we enable support for 5 level paging. So introduce a couple of helpers that encapsulate this mask/value pair matching, and wire them up in the code. No functional change intended, the actual handling of translation level -1 will be added in a subsequent patch. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> [maz: folded in changes suggested by Mark] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231128140400.3132145-2-ardb@google.com
2023-10-09KVM: arm64: Expose MOPS instructions to guestsKristina Martsenko
Expose the Armv8.8 FEAT_MOPS feature to guests in the ID register and allow the MOPS instructions to be run in a guest. Only expose MOPS if the whole system supports it. Note, it is expected that guests do not use these instructions on MMIO, similarly to other instructions where ESR_EL2.ISV==0 such as LDP/STP. Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230922112508.1774352-3-kristina.martsenko@arm.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-10-09KVM: arm64: Add handler for MOPS exceptionsKristina Martsenko
An Armv8.8 FEAT_MOPS main or epilogue instruction will take an exception if executed on a CPU with a different MOPS implementation option (A or B) than the CPU where the preceding prologue instruction ran. In this case the OS exception handler is expected to reset the registers and restart execution from the prologue instruction. A KVM guest may use the instructions at EL1 at times when the guest is not able to handle the exception, expecting that the instructions will only run on one CPU (e.g. when running UEFI boot services in the guest). As KVM may reschedule the guest between different types of CPUs at any time (on an asymmetric system), it needs to also handle the resulting exception itself in case the guest is not able to. A similar situation will also occur in the future when live migrating a guest from one type of CPU to another. Add handling for the MOPS exception to KVM. The handling can be shared with the EL0 exception handler, as the logic and register layouts are the same. The exception can be handled right after exiting a guest, which avoids the cost of returning to the host exit handler. Similarly to the EL0 exception handler, in case the main or epilogue instruction is being single stepped, it makes sense to finish the step before executing the prologue instruction, so advance the single step state machine. Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230922112508.1774352-2-kristina.martsenko@arm.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>