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2024-08-07KVM: arm64: Tidying up PAuth code in KVMFuad Tabba1-3/+2
Tidy up some of the PAuth trapping code to clear up some comments and avoid clang/checkpatch warnings. Also, don't bother setting PAuth HCR_EL2 bits in pKVM, since it's handled by the hypervisor. Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240722163311.1493879-1-tabba@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-04KVM: arm64: Refactor CPACR trap bit setting/clearing to use ELx formatFuad Tabba1-3/+2
When setting/clearing CPACR bits for EL0 and EL1, use the ELx format of the bits, which covers both. This makes the code clearer, and reduces the chances of accidentally missing a bit. No functional change intended. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-9-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-06-04KVM: arm64: Eagerly restore host fpsimd/sve state in pKVMFuad Tabba1-1/+15
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 Tabba1-0/+5
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>
2024-05-03Merge branch kvm-arm64/pkvm-6.10 into kvmarm-master/nextMarc Zyngier1-6/+4
* 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 Zyngier1-3/+1
* 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 Tabba1-4/+2
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 Tabba1-1/+1
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 Tabba1-1/+1
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>
2024-04-20KVM: arm64: Drop trapping of PAuth instructions/keysMarc Zyngier1-2/+0
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: Configure HCR_EL2 for FEAT_NV2Marc Zyngier1-1/+1
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 Zyngier1-1/+1
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: Add accessor for per-CPU stateMarc Zyngier1-2/+2
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>
2023-10-09KVM: arm64: Add handler for MOPS exceptionsKristina Martsenko1-0/+2
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>
2023-08-31Merge tag 'kvmarm-6.6' of ↵Paolo Bonzini1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for Linux 6.6 - Add support for TLB range invalidation of Stage-2 page tables, avoiding unnecessary invalidations. Systems that do not implement range invalidation still rely on a full invalidation when dealing with large ranges. - Add infrastructure for forwarding traps taken from a L2 guest to the L1 guest, with L0 acting as the dispatcher, another baby step towards the full nested support. - Simplify the way we deal with the (long deprecated) 'CPU target', resulting in a much needed cleanup. - Fix another set of PMU bugs, both on the guest and host sides, as we seem to never have any shortage of those... - Relax the alignment requirements of EL2 VA allocations for non-stack allocations, as we were otherwise wasting a lot of that precious VA space. - The usual set of non-functional cleanups, although I note the lack of spelling fixes...
2023-07-26KVM: arm64: Use the appropriate feature trap register when activating trapsFuad Tabba1-1/+1
Instead of writing directly to cptr_el2, use the helper that selects which feature trap register to write to based on the KVM mode. Fixes: 75c76ab5a641 ("KVM: arm64: Rework CPTR_EL2 programming for HVHE configuration") Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230724123829.2929609-7-tabba@google.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-07-11KVM: arm64: Replace vCPU target with a configuration flagOliver Upton1-1/+1
The value of kvm_vcpu_arch::target has been used to determine if a vCPU has actually been initialized. Storing this as an integer is needless at this point, as KVM doesn't do any microarch-specific emulation in the first place. Instead, all we care about is whether or not the vCPU has been initialized. Delete the field in favor of a vCPU configuration flag indicating if KVM_ARM_VCPU_INIT has completed for the vCPU. Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230710193140.1706399-4-oliver.upton@linux.dev
2023-07-01Merge tag 'kvmarm-6.5' of ↵Paolo Bonzini1-12/+16
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for 6.5 - Eager page splitting optimization for dirty logging, optionally allowing for a VM to avoid the cost of block splitting in the stage-2 fault path. - Arm FF-A proxy for pKVM, allowing a pKVM host to safely interact with services that live in the Secure world. pKVM intervenes on FF-A calls to guarantee the host doesn't misuse memory donated to the hyp or a pKVM guest. - Support for running the split hypervisor with VHE enabled, known as 'hVHE' mode. This is extremely useful for testing the split hypervisor on VHE-only systems, and paves the way for new use cases that depend on having two TTBRs available at EL2. - Generalized framework for configurable ID registers from userspace. KVM/arm64 currently prevents arbitrary CPU feature set configuration from userspace, but the intent is to relax this limitation and allow userspace to select a feature set consistent with the CPU. - Enable the use of Branch Target Identification (FEAT_BTI) in the hypervisor. - Use a separate set of pointer authentication keys for the hypervisor when running in protected mode, as the host is untrusted at runtime. - Ensure timer IRQs are consistently released in the init failure paths. - Avoid trapping CTR_EL0 on systems with Enhanced Virtualization Traps (FEAT_EVT), as it is a register commonly read from userspace. - Erratum workaround for the upcoming AmpereOne part, which has broken hardware A/D state management. As a consequence of the hVHE series reworking the arm64 software features framework, the for-next/module-alloc branch from the arm64 tree comes along for the ride.
2023-06-13KVM: arm64: Rework CPTR_EL2 programming for HVHE configurationMarc Zyngier1-12/+16
Just like we repainted the early arm64 code, we need to update the CPTR_EL2 accesses that are taking place in the nVHE code when hVHE is used, making them look as if they were CPACR_EL1 accesses. Just like the VHE code. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230609162200.2024064-14-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-05-30KVM: arm64: Populate fault info for watchpointAkihiko Odaki1-0/+2
When handling ESR_ELx_EC_WATCHPT_LOW, far_el2 member of struct kvm_vcpu_fault_info will be copied to far member of struct kvm_debug_exit_arch and exposed to the userspace. The userspace will see stale values from older faults if the fault info does not get populated. Fixes: 8fb2046180a0 ("KVM: arm64: Move early handlers to per-EC handlers") Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230530024651.10014-1-akihiko.odaki@daynix.com Cc: stable@vger.kernel.org
2023-04-13KVM: arm64: nvhe: Synchronise with page table walker on vcpu runMarc Zyngier1-0/+18
When taking an exception between the EL1&0 translation regime and the EL2 translation regime, the page table walker is allowed to complete the walks started from EL0 or EL1 while running at EL2. It means that altering the system registers that define the EL1&0 translation regime is fraught with danger *unless* we wait for the completion of such walk with a DSB (R_LFHQG and subsequent statements in the ARM ARM). We already did the right thing for other external agents (SPE, TRBE), but not the PTW. Rework the existing SPE/TRBE synchronisation to include the PTW, and add the missing DSB on guest exit. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
2022-11-01KVM: arm64: Fix SMPRI_EL1/TPIDR2_EL0 trapping on VHEMarc Zyngier1-26/+0
The trapping of SMPRI_EL1 and TPIDR2_EL0 currently only really work on nVHE, as only this mode uses the fine-grained trapping that controls these two registers. Move the trapping enable/disable code into __{de,}activate_traps_common(), allowing it to be called when it actually matters on VHE, and remove the flipping of EL2 control for TPIDR2_EL0, which only affects the host access of this register. Fixes: 861262ab8627 ("KVM: arm64: Handle SME host state when running guests") Reported-by: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/86bkpqer4z.wl-maz@kernel.org
2022-09-29KVM: arm64: Fix comment typo in nvhe/switch.cWei-Lin Chang1-1/+1
Fix the comment of __hyp_vgic_restore_state() from saying VEH to VHE, also change the underscore to a dash to match the comment above __hyp_vgic_save_state(). Signed-off-by: Wei-Lin Chang <r09922117@csie.ntu.edu.tw> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220929042839.24277-1-r09922117@csie.ntu.edu.tw
2022-07-27Merge branch kvm-arm64/nvhe-stacktrace into kvmarm-master/nextMarc Zyngier1-0/+6
* kvm-arm64/nvhe-stacktrace: (27 commits) : . : Add an overflow stack to the nVHE EL2 code, allowing : the implementation of an unwinder, courtesy of : Kalesh Singh. From the cover letter (slightly edited): : : "nVHE has two modes of operation: protected (pKVM) and unprotected : (conventional nVHE). Depending on the mode, a slightly different approach : is used to dump the hypervisor stacktrace but the core unwinding logic : remains the same. : : * Protected nVHE (pKVM) stacktraces: : : In protected nVHE mode, the host cannot directly access hypervisor memory. : : The hypervisor stack unwinding happens in EL2 and is made accessible to : the host via a shared buffer. Symbolizing and printing the stacktrace : addresses is delegated to the host and happens in EL1. : : * Non-protected (Conventional) nVHE stacktraces: : : In non-protected mode, the host is able to directly access the hypervisor : stack pages. : : The hypervisor stack unwinding and dumping of the stacktrace is performed : by the host in EL1, as this avoids the memory overhead of setting up : shared buffers between the host and hypervisor." : : Additional patches from Oliver Upton and Marc Zyngier, tidying up : the initial series. : . arm64: Update 'unwinder howto' KVM: arm64: Don't open code ARRAY_SIZE() KVM: arm64: Move nVHE-only helpers into kvm/stacktrace.c KVM: arm64: Make unwind()/on_accessible_stack() per-unwinder functions KVM: arm64: Move nVHE stacktrace unwinding into its own compilation unit KVM: arm64: Move PROTECTED_NVHE_STACKTRACE around KVM: arm64: Introduce pkvm_dump_backtrace() KVM: arm64: Implement protected nVHE hyp stack unwinder KVM: arm64: Save protected-nVHE (pKVM) hyp stacktrace KVM: arm64: Stub implementation of pKVM HYP stack unwinder KVM: arm64: Allocate shared pKVM hyp stacktrace buffers KVM: arm64: Add PROTECTED_NVHE_STACKTRACE Kconfig KVM: arm64: Introduce hyp_dump_backtrace() KVM: arm64: Implement non-protected nVHE hyp stack unwinder KVM: arm64: Prepare non-protected nVHE hypervisor stacktrace KVM: arm64: Stub implementation of non-protected nVHE HYP stack unwinder KVM: arm64: On stack overflow switch to hyp overflow_stack arm64: stacktrace: Add description of stacktrace/common.h arm64: stacktrace: Factor out common unwind() arm64: stacktrace: Handle frame pointer from different address spaces ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-07-26KVM: arm64: Prepare non-protected nVHE hypervisor stacktraceKalesh Singh1-0/+6
In non-protected nVHE mode (non-pKVM) the host can directly access hypervisor memory; and unwinding of the hypervisor stacktrace is done from EL1 to save on memory for shared buffers. To unwind the hypervisor stack from EL1 the host needs to know the starting point for the unwind and information that will allow it to translate hypervisor stack addresses to the corresponding kernel addresses. This patch sets up this book keeping. It is made use of later in the series. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220726073750.3219117-10-kaleshsingh@google.com
2022-07-17Merge branch kvm-arm64/misc-5.20 into kvmarm-master/nextMarc Zyngier1-1/+1
* kvm-arm64/misc-5.20: : . : Misc fixes for 5.20: : : - Tidy up the hyp/nvhe Makefile : : - Fix functions pointlessly returning a void value : : - Fix vgic_init selftest to handle the GICv3-on-v3 case : : - Fix hypervisor symbolisation when CONFIG_RANDOMIZE_BASE=y : . KVM: arm64: Fix hypervisor address symbolization KVM: arm64: selftests: Add support for GICv2 on v3 KVM: arm64: Don't return from void function KVM: arm64: nvhe: Add intermediates to 'targets' instead of extra-y KVM: arm64: nvhe: Rename confusing obj-y Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-07-06KVM: arm64: Don't return from void functionQuentin Perret1-1/+1
Although harmless, the return statement in kvm_unexpected_el2_exception is rather confusing as the function itself has a void return type. The C standard is also pretty clear that "A return statement with an expression shall not appear in a function whose return type is void". Given that this return statement does not seem to add any actual value, let's not pointlessly violate the standard. Build-tested with GCC 10 and CLANG 13 for good measure, the disassembled code is identical with or without the return statement. Fixes: e9ee186bb735 ("KVM: arm64: Add kvm_extable for vaxorcism code") Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220705142310.3847918-1-qperret@google.com
2022-06-09KVM: arm64: Move FP state ownership from flag to a tristateMarc Zyngier1-2/+2
The KVM FP code uses a pair of flags to denote three states: - FP_ENABLED set: the guest owns the FP state - FP_HOST set: the host owns the FP state - FP_ENABLED and FP_HOST clear: nobody owns the FP state at all and both flags set is an illegal state, which nothing ever checks for... As it turns out, this isn't really a good match for flags, and we'd be better off if this was a simpler tristate, each state having a name that actually reflect the state: - FP_STATE_FREE - FP_STATE_HOST_OWNED - FP_STATE_GUEST_OWNED Kill the two flags, and move over to an enum encoding these three states. This results in less confusing code, and less risk of ending up in the uncharted territory of a 4th state if we forget to clear one of the two flags. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com>
2022-06-09KVM: arm64: Drop FP_FOREIGN_STATE from the hypervisor codeMarc Zyngier1-1/+1
The vcpu KVM_ARM64_FP_FOREIGN_FPSTATE flag tracks the thread's own TIF_FOREIGN_FPSTATE so that we can evaluate just before running the vcpu whether it the FP regs contain something that is owned by the vcpu or not by updating the rest of the FP flags. We do this in the hypervisor code in order to make sure we're in a context where we are not interruptible. But we already have a hook in the run loop to generate this flag. We may as well update the FP flags directly and save the pointless flag tracking. Whilst we're at it, rename update_fp_enabled() to guest_owns_fp_regs() to indicate what the leftover of this helper actually do. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Reiji Watanabe <reijiw@google.com> Reviewed-by: Mark Brown <broonie@kernel.org>
2022-05-16Merge branch kvm-arm64/misc-5.19 into kvmarm-master/nextMarc Zyngier1-21/+4
* kvm-arm64/misc-5.19: : . : Misc fixes and general improvements for KVMM/arm64: : : - Better handle out of sequence sysregs in the global tables : : - Remove a couple of unnecessary loads from constant pool : : - Drop unnecessary pKVM checks : : - Add all known M1 implementations to the SEIS workaround : : - Cleanup kerneldoc warnings : . KVM: arm64: vgic-v3: List M1 Pro/Max as requiring the SEIS workaround KVM: arm64: pkvm: Don't mask already zeroed FEAT_SVE KVM: arm64: pkvm: Drop unnecessary FP/SIMD trap handler KVM: arm64: nvhe: Eliminate kernel-doc warnings KVM: arm64: Avoid unnecessary absolute addressing via literals KVM: arm64: Print emulated register table name when it is unsorted KVM: arm64: Don't BUG_ON() if emulated register table is unsorted Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-05-16Merge branch kvm-arm64/per-vcpu-host-pmu-data into kvmarm-master/nextMarc Zyngier1-14/+11
* kvm-arm64/per-vcpu-host-pmu-data: : . : Pass the host PMU state in the vcpu to avoid the use of additional : shared memory between EL1 and EL2 (this obviously only applies : to nVHE and Protected setups). : : Patches courtesy of Fuad Tabba. : . KVM: arm64: pmu: Restore compilation when HW_PERF_EVENTS isn't selected KVM: arm64: Reenable pmu in Protected Mode KVM: arm64: Pass pmu events to hyp via vcpu KVM: arm64: Repack struct kvm_pmu to reduce size KVM: arm64: Wrapper for getting pmu_events Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-05-16KVM: arm64: pmu: Restore compilation when HW_PERF_EVENTS isn't selectedMarc Zyngier1-0/+5
Moving kvm_pmu_events into the vcpu (and refering to it) broke the somewhat unusual case where the kernel has no support for a PMU at all. In order to solve this, move things around a bit so that we can easily avoid refering to the pmu structure outside of PMU-aware code. As a bonus, pmu.c isn't compiled in when HW_PERF_EVENTS isn't selected. Reported-by: kernel test robot <lkp@intel.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/202205161814.KQHpOzsJ-lkp@intel.com
2022-05-15KVM: arm64: Pass pmu events to hyp via vcpuFuad Tabba1-14/+6
Instead of the host accessing hyp data directly, pass the pmu events of the current cpu to hyp via the vcpu. This adds 64 bits (in two fields) to the vcpu that need to be synced before every vcpu run in nvhe and protected modes. However, it isolates the hypervisor from the host, which allows us to use pmu in protected mode in a subsequent patch. No visible side effects in behavior intended. Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Oliver Upton <oupton@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220510095710.148178-4-tabba@google.com
2022-05-10KVM: arm64: pkvm: Drop unnecessary FP/SIMD trap handlerOliver Upton1-18/+1
The pVM-specific FP/SIMD trap handler just calls straight into the generic trap handler. Avoid the indirection and just call the hyp handler directly. Note that the BUILD_BUG_ON() pattern is repeated in pvm_init_traps_aa64pfr0(), which is likely a better home for it. No functional change intended. Signed-off-by: Oliver Upton <oupton@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220509162559.2387784-2-oupton@google.com
2022-05-06KVM: arm64: nvhe: Eliminate kernel-doc warningsRandy Dunlap1-4/+4
Don't use begin-kernel-doc notation (/**) for comments that are not in kernel-doc format. This prevents these kernel-doc warnings: arch/arm64/kvm/hyp/nvhe/switch.c:126: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * Disable host events, enable guest events arch/arm64/kvm/hyp/nvhe/switch.c:146: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * Disable guest events, enable host events arch/arm64/kvm/hyp/nvhe/switch.c:164: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * Handler for protected VM restricted exceptions. arch/arm64/kvm/hyp/nvhe/switch.c:176: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst * Handler for protected VM MSR, MRS or System instruction execution in AArch64. arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: Function parameter or member 'vcpu' not described in 'kvm_handle_pvm_fpsimd' arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: Function parameter or member 'exit_code' not described in 'kvm_handle_pvm_fpsimd' arch/arm64/kvm/hyp/nvhe/switch.c:196: warning: expecting prototype for Handler for protected floating(). Prototype was for kvm_handle_pvm_fpsimd() instead Fixes: 09cf57eba304 ("KVM: arm64: Split hyp/switch.c to VHE/nVHE") Fixes: 1423afcb4117 ("KVM: arm64: Trap access to pVM restricted features") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: kernel test robot <lkp@intel.com> Cc: Fuad Tabba <tabba@google.com> Cc: Marc Zyngier <maz@kernel.org> Cc: David Brazdil <dbrazdil@google.com> Cc: James Morse <james.morse@arm.com> Cc: Alexandru Elisei <alexandru.elisei@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220430050123.2844-1-rdunlap@infradead.org
2022-05-04Merge branch kvm-arm64/hyp-stack-guard into kvmarm-master/nextMarc Zyngier1-1/+6
* kvm-arm64/hyp-stack-guard: : . : Harden the EL2 stack by providing stack guards, courtesy of : Kalesh Singh. : . KVM: arm64: Symbolize the nVHE HYP addresses KVM: arm64: Detect and handle hypervisor stack overflows KVM: arm64: Add guard pages for pKVM (protected nVHE) hypervisor stack KVM: arm64: Add guard pages for KVM nVHE hypervisor stack KVM: arm64: Introduce pkvm_alloc_private_va_range() KVM: arm64: Introduce hyp_alloc_private_va_range() Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-04-28KVM: arm64: Detect and handle hypervisor stack overflowsKalesh Singh1-1/+6
The hypervisor stacks (for both nVHE Hyp mode and nVHE protected mode) are aligned such that any valid stack address has PAGE_SHIFT bit as 1. This allows us to conveniently check for overflow in the exception entry without corrupting any GPRs. We won't recover from a stack overflow so panic the hypervisor. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220420214317.3303360-6-kaleshsingh@google.com
2022-04-22KVM: arm64: Trap SME usage in guestMark Brown1-0/+30
SME defines two new traps which need to be enabled for guests to ensure that they can't use SME, one for the main SME operations which mirrors the traps for SVE and another for access to TPIDR2 in SCTLR_EL2. For VHE manage SMEN along with ZEN in activate_traps() and the FP state management callbacks, along with SCTLR_EL2.EnTPIDR2. There is no existing dynamic management of SCTLR_EL2. For nVHE manage TSM in activate_traps() along with the fine grained traps for TPIDR2 and SMPRI. There is no existing dynamic management of fine grained traps. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220419112247.711548-26-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-01-07Merge tag 'kvmarm-5.17' of ↵Paolo Bonzini1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 updates for Linux 5.16 - Simplification of the 'vcpu first run' by integrating it into KVM's 'pid change' flow - Refactoring of the FP and SVE state tracking, also leading to a simpler state and less shared data between EL1 and EL2 in the nVHE case - Tidy up the header file usage for the nvhe hyp object - New HYP unsharing mechanism, finally allowing pages to be unmapped from the Stage-1 EL2 page-tables - Various pKVM cleanups around refcounting and sharing - A couple of vgic fixes for bugs that would trigger once the vcpu xarray rework is merged, but not sooner - Add minimal support for ARMv8.7's PMU extension - Rework kvm_pgtable initialisation ahead of the NV work - New selftest for IRQ injection - Teach selftests about the lack of default IPA space and page sizes - Expand sysreg selftest to deal with Pointer Authentication - The usual bunch of cleanups and doc update
2021-11-24KVM: arm64: Move pkvm's special 32bit handling into a generic infrastructureMarc Zyngier1-7/+1
Protected KVM is trying to turn AArch32 exceptions into an illegal exception entry. Unfortunately, it does that in a way that is a bit abrupt, and too early for PSTATE to be available. Instead, move it to the fixup code, which is a more reasonable place for it. This will also be useful for the NV code. Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-11-22KVM: arm64: Stop mapping current thread_info at EL2Marc Zyngier1-1/+0
Now that we can track an equivalent of TIF_FOREIGN_FPSTATE, drop the mapping of current's thread_info at EL2. Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-10-18KVM: arm64: pkvm: Give priority to standard traps over pvm handlingMarc Zyngier1-4/+7
Checking for pvm handling first means that we cannot handle ptrauth traps or apply any of the workarounds (GICv3 or TX2 #219). Flip the order around. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20211013120346.2926621-12-maz@kernel.org
2021-10-18KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array()Marc Zyngier1-2/+2
Passing a VM pointer around is odd, and results in extra work on VHE. Follow the rest of the design that uses the vcpu instead, and let the nVHE code look into the struct kvm as required. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20211013120346.2926621-11-maz@kernel.org
2021-10-18KVM: arm64: pkvm: Move kvm_handle_pvm_restricted aroundMarc Zyngier1-12/+0
Place kvm_handle_pvm_restricted() next to its little friends such as kvm_handle_pvm_sysreg(). This allows to make inject_undef64() static. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20211013120346.2926621-10-maz@kernel.org
2021-10-18KVM: arm64: pkvm: Consolidate include filesMarc Zyngier1-2/+1
kvm_fixed_config.h is pkvm specific, and would be better placed near its users. At the same time, include/nvhe/sys_regs.h is now almost empty. Merge the two into arch/arm64/kvm/hyp/include/nvhe/fixed_config.h. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20211013120346.2926621-9-maz@kernel.org
2021-10-18KVM: arm64: pkvm: Preserve pending SError on exit from AArch32Marc Zyngier1-1/+2
Don't drop a potential SError when a guest gets caught red-handed running AArch32 code. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Fuad Tabba <tabba@google.com> Tested-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20211013120346.2926621-8-maz@kernel.org
2021-10-11KVM: arm64: Handle protected guests at 32 bitsFuad Tabba1-0/+34
Protected KVM does not support protected AArch32 guests. However, it is possible for the guest to force run AArch32, potentially causing problems. Add an extra check so that if the hypervisor catches the guest doing that, it can prevent the guest from running again by resetting vcpu->arch.target and returning ARM_EXCEPTION_IL. If this were to happen, The VMM can try and fix it by re- initializing the vcpu with KVM_ARM_VCPU_INIT, however, this is likely not possible for protected VMs. Adapted from commit 22f553842b14 ("KVM: arm64: Handle Asymmetric AArch32 systems") Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211010145636.1950948-12-tabba@google.com
2021-10-11KVM: arm64: Trap access to pVM restricted featuresFuad Tabba1-0/+57
Trap accesses to restricted features for VMs running in protected mode. Access to feature registers are emulated, and only supported features are exposed to protected VMs. Accesses to restricted registers as well as restricted instructions are trapped, and an undefined exception is injected into the protected guests, i.e., with EC = 0x0 (unknown reason). This EC is the one used, according to the Arm Architecture Reference Manual, for unallocated or undefined system registers or instructions. Only affects the functionality of protected VMs. Otherwise, should not affect non-protected VMs when KVM is running in protected mode. Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211010145636.1950948-11-tabba@google.com
2021-10-11KVM: arm64: Add handlers for protected VM System RegistersFuad Tabba1-0/+1
Add system register handlers for protected VMs. These cover Sys64 registers (including feature id registers), and debug. No functional change intended as these are not hooked in yet to the guest exit handlers introduced earlier. So when trapping is triggered, the exit handlers let the host handle it, as before. Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211010145636.1950948-8-tabba@google.com
2021-10-11KVM: arm64: Pass struct kvm to per-EC handlersFuad Tabba1-1/+1
We need struct kvm to check for protected VMs to be able to pick the right handlers for them 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/20211010145636.1950948-5-tabba@google.com