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2025-05-21KVM: arm64: np-guest CMOs with PMD_SIZE fixmapVincent Donnefort
With the introduction of stage-2 huge mappings in the pKVM hypervisor, guest pages CMO is needed for PMD_SIZE size. Fixmap only supports PAGE_SIZE and iterating over the huge-page is time consuming (mostly due to TLBI on hyp_fixmap_unmap) which is a problem for EL2 latency. Introduce a shared PMD_SIZE fixmap (hyp_fixblock_map/hyp_fixblock_unmap) to improve guest page CMOs when stage-2 huge mappings are installed. On a Pixel6, the iterative solution resulted in a latency of ~700us, while the PMD_SIZE fixmap reduces it to ~100us. Because of the horrendous private range allocation that would be necessary, this is disabled for 64KiB pages systems. Suggested-by: Quentin Perret <qperret@google.com> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250521124834.1070650-11-vdonnefort@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21KVM: arm64: Introduce for_each_hyp_pageVincent Donnefort
Add a helper to iterate over the hypervisor vmemmap. This will be particularly handy with the introduction of huge mapping support for the np-guest stage-2. Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Link: https://lore.kernel.org/r/20250521124834.1070650-3-vdonnefort@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21Merge branch kvm-arm64/pkvm-selftest-6.16 into kvm-arm64/pkvm-np-thp-6.16Marc Zyngier
* kvm-arm64/pkvm-selftest-6.16: : . : pKVM selftests covering the memory ownership transitions by : Quentin Perret. From the initial cover letter: : : "We have recently found a bug [1] in the pKVM memory ownership : transitions by code inspection, but it could have been caught with a : test. : : Introduce a boot-time selftest exercising all the known pKVM memory : transitions and importantly checks the rejection of illegal transitions. : : The new test is hidden behind a new Kconfig option separate from : CONFIG_EL2_NVHE_DEBUG on purpose as that has side effects on the : transition checks ([1] doesn't reproduce with EL2 debug enabled). : : [1] https://lore.kernel.org/kvmarm/20241128154406.602875-1-qperret@google.com/" : . KVM: arm64: Extend pKVM selftest for np-guests KVM: arm64: Selftest for pKVM transitions KVM: arm64: Don't WARN from __pkvm_host_share_guest() KVM: arm64: Add .hyp.data section Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06KVM: arm64: Extend pKVM selftest for np-guestsQuentin Perret
The pKVM selftest intends to test as many memory 'transitions' as possible, so extend it to cover sharing pages with non-protected guests, including in the case of multi-sharing. Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250416160900.3078417-5-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06KVM: arm64: Selftest for pKVM transitionsQuentin Perret
We have recently found a bug [1] in the pKVM memory ownership transitions by code inspection, but it could have been caught with a test. Introduce a boot-time selftest exercising all the known pKVM memory transitions and importantly checks the rejection of illegal transitions. The new test is hidden behind a new Kconfig option separate from CONFIG_EL2_NVHE_DEBUG on purpose as that has side effects on the transition checks ([1] doesn't reproduce with EL2 debug enabled). [1] https://lore.kernel.org/kvmarm/20241128154406.602875-1-qperret@google.com/ Suggested-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250416160900.3078417-4-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06KVM: arm64: Add .hyp.data sectionDavid Brazdil
The hypervisor has not needed its own .data section because all globals were either .rodata or .bss. To avoid having to initialize future data-structures at run-time, let's introduce add a .data section to the hypervisor. Signed-off-by: David Brazdil <dbrazdil@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250416160900.3078417-2-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28KVM: arm64: Move hyp state to hyp_vmemmapQuentin Perret
Tracking the hypervisor's ownership state into struct hyp_page has several benefits, including allowing far more efficient lookups (no page-table walk needed) and de-corelating the state from the presence of a mapping. This will later allow to map pages into EL2 stage-1 less proactively which is generally a good thing for security. And in the future this will help with tracking the state of pages mapped into the hypervisor's private range without requiring an alias into the 'linear map' range. Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250416152648.2982950-6-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28KVM: arm64: Introduce {get,set}_host_state() helpersQuentin Perret
Instead of directly accessing the host_state member in struct hyp_page, introduce static inline accessors to do it. The future hyp_state member will follow the same pattern as it will need some logic in the accessors. Reviewed-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20250416152648.2982950-5-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-01-12Merge branch kvm-arm64/pkvm-fixed-features-6.14 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-fixed-features-6.14: (24 commits) : . : Complete rework of the pKVM handling of features, catching up : with the rest of the code deals with it these days. : Patches courtesy of Fuad Tabba. From the cover letter: : : "This patch series uses the vm's feature id registers to track the : supported features, a framework similar to nested virt to set the : trap values, and removes the need to store cptr_el2 per vcpu in : favor of setting its value when traps are activated, as VHE mode : does." : : This branch drags the arm64/for-next/cpufeature branch to solve : ugly conflicts in -next. : . KVM: arm64: Fix FEAT_MTE in pKVM KVM: arm64: Use kvm_vcpu_has_feature() directly for struct kvm KVM: arm64: Convert the SVE guest vcpu flag to a vm flag KVM: arm64: Remove PtrAuth guest vcpu flag KVM: arm64: Fix the value of the CPTR_EL2 RES1 bitmask for nVHE KVM: arm64: Refactor kvm_reset_cptr_el2() KVM: arm64: Calculate cptr_el2 traps on activating traps KVM: arm64: Remove redundant setting of HCR_EL2 trap bit KVM: arm64: Remove fixed_config.h header KVM: arm64: Rework specifying restricted features for protected VMs KVM: arm64: Set protected VM traps based on its view of feature registers KVM: arm64: Fix RAS trapping in pKVM for protected VMs KVM: arm64: Initialize feature id registers for protected VMs KVM: arm64: Use KVM extension checks for allowed protected VM capabilities KVM: arm64: Remove KVM_ARM_VCPU_POWER_OFF from protected VMs allowed features in pKVM KVM: arm64: Move checking protected vcpu features to a separate function KVM: arm64: Group setting traps for protected VMs by control register KVM: arm64: Consolidate allowed and restricted VM feature checks arm64/sysreg: Get rid of CPACR_ELx SysregFields arm64/sysreg: Convert *_EL12 accessors to Mapping ... Signed-off-by: Marc Zyngier <maz@kernel.org> # Conflicts: # arch/arm64/kvm/fpsimd.c # arch/arm64/kvm/hyp/nvhe/pkvm.c
2024-12-20KVM: arm64: Remove fixed_config.h headerFuad Tabba
The few remaining items needed in fixed_config.h are better suited for pkvm.h. Move them there and delete it. No functional change intended. Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20241216105057.579031-11-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-12-20KVM: arm64: Move host page ownership tracking to the hyp vmemmapQuentin Perret
We currently store part of the page-tracking state in PTE software bits for the host, guests and the hypervisor. This is sub-optimal when e.g. sharing pages as this forces to break block mappings purely to support this software tracking. This causes an unnecessarily fragmented stage-2 page-table for the host in particular when it shares pages with Secure, which can lead to measurable regressions. Moreover, having this state stored in the page-table forces us to do multiple costly walks on the page transition path, hence causing overhead. In order to work around these problems, move the host-side page-tracking logic from SW bits in its stage-2 PTEs to the hypervisor's vmemmap. Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Link: https://lore.kernel.org/r/20241218194059.3670226-5-qperret@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-11-12KVM: arm64: Pass on SVE mapping failuresJames Clark
This function can fail but its return value isn't passed onto the caller. Presumably this could result in a broken state. Fixes: 66d5b53e20a6 ("KVM: arm64: Allocate memory mapped at hyp for host sve state in pKVM") Signed-off-by: James Clark <james.clark@linaro.org> Reviewed-by: Fuad Tabba <tabba@google.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241112105604.795809-1-james.clark@linaro.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-10-23KVM: arm64: Don't map 'kvm_vgic_global_state' at EL2 with pKVMWill Deacon
Now that 'kvm_vgic_global_state' is no longer needed for ICC_CTLR_EL1 emulation on machines with a broken SEIS implementation, drop the pKVM hypervisor mapping of the page. Note that kvm_vgic_global_state is still mapped in non-protected hypervisor configurations (i.e. {n,h}VHE) through the rodata section mapping. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241022144016.27350-3-will@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-20KVM: arm64: Fix __pkvm_init_switch_pgd call ABIPierre-Clément Tosi
Fix the mismatch between the (incorrect) C signature, C call site, and asm implementation by aligning all three on an API passing the parameters (pgd and SP) separately, instead of as a bundled struct. Remove the now unnecessary memory accesses while the MMU is off from the asm, which simplifies the C caller (as it does not need to convert a VA struct pointer to PA) and makes the code slightly more robust by offsetting the struct fields from C and properly expressing the call to the C compiler (e.g. type checker and kCFI). Fixes: f320bc742bc2 ("KVM: arm64: Prepare the creation of s1 mappings at EL2") Signed-off-by: Pierre-Clément Tosi <ptosi@google.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20240610063244.2828978-3-ptosi@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: Allocate memory mapped at hyp for host sve state in pKVMFuad Tabba
Protected mode needs to maintain (save/restore) the host's sve state, rather than relying on the host kernel to do that. This is to avoid leaking information to the host about guests and the type of operations they are performing. As a first step towards that, allocate memory mapped at hyp, per cpu, for the host sve state. The following patch will use this memory to save/restore the host state. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Fuad Tabba <tabba@google.com> Link: https://lore.kernel.org/r/20240603122852.3923848-6-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>
2024-04-12KVM: 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>
2023-11-27KVM: arm64: Convert translation level parameter to s8Ryan Roberts
With the introduction of FEAT_LPA2, the Arm ARM adds a new level of translation, level -1, so levels can now be in the range [-1;3]. 3 is always the last level and the first level is determined based on the number of VA bits in use. Convert level variables to use a signed type in preparation for supporting this new level -1. Since the last level is always anchored at 3, and the first level varies to suit the number of VA/IPA bits, take the opportunity to replace KVM_PGTABLE_MAX_LEVELS with the 2 macros KVM_PGTABLE_FIRST_LEVEL and KVM_PGTABLE_LAST_LEVEL. This removes the assumption from the code that levels run from 0 to KVM_PGTABLE_MAX_LEVELS - 1, which will soon no longer be true. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231127111737.1897081-9-ryan.roberts@arm.com
2023-08-26KVM: arm64: Remove size-order align in the nVHE hyp private VA rangeVincent Donnefort
commit f922c13e778d ("KVM: arm64: Introduce pkvm_alloc_private_va_range()") and commit 92abe0f81e13 ("KVM: arm64: Introduce hyp_alloc_private_va_range()") added an alignment for the start address of any allocation into the nVHE hypervisor private VA range. This alignment (order of the size of the allocation) intends to enable efficient stack verification (if the PAGE_SHIFT bit is zero, the stack pointer is on the guard page and a stack overflow occurred). But this is only necessary for stack allocation and can waste a lot of VA space. So instead make stack-specific functions, handling the guard page requirements, while other users (e.g. fixmap) will only get page alignment. Reviewed-by: Kalesh Singh <kaleshsingh@google.com> Signed-off-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230811112037.1147863-1-vdonnefort@google.com
2023-06-01KVM: arm64: Allocate pages for hypervisor FF-A mailboxesWill Deacon
The FF-A proxy code needs to allocate its own buffer pair for communication with EL3 and for forwarding calls from the host at EL1. Reserve a couple of pages for this purpose and use them to initialise the hypervisor's FF-A buffer structure. Co-developed-by: Andrew Walbran <qwandor@google.com> Signed-off-by: Andrew Walbran <qwandor@google.com> Signed-off-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20230523101828.7328-4-will@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-06-01KVM: arm64: Probe FF-A version and host/hyp partition ID during initWill Deacon
Probe FF-A during pKVM initialisation so that we can detect any inconsistencies in the version or partition ID early on. Signed-off-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20230523101828.7328-3-will@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2022-12-05Merge branch kvm-arm64/pkvm-vcpu-state into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-vcpu-state: (25 commits) : . : Large drop of pKVM patches from Will Deacon and co, adding : a private vm/vcpu state at EL2, managed independently from : the EL1 state. From the cover letter: : : "This is version six of the pKVM EL2 state series, extending the pKVM : hypervisor code so that it can dynamically instantiate and manage VM : data structures without the host being able to access them directly. : These structures consist of a hyp VM, a set of hyp vCPUs and the stage-2 : page-table for the MMU. The pages used to hold the hypervisor structures : are returned to the host when the VM is destroyed." : . KVM: arm64: Use the pKVM hyp vCPU structure in handle___kvm_vcpu_run() KVM: arm64: Don't unnecessarily map host kernel sections at EL2 KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2 KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2 KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the host KVM: arm64: Return guest memory from EL2 via dedicated teardown memcache KVM: arm64: Instantiate guest stage-2 page-tables at EL2 KVM: arm64: Consolidate stage-2 initialisation into a single function KVM: arm64: Add generic hyp_memcache helpers KVM: arm64: Provide I-cache invalidation by virtual address at EL2 KVM: arm64: Initialise hypervisor copies of host symbols unconditionally KVM: arm64: Add per-cpu fixmap infrastructure at EL2 KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1 KVM: arm64: Add infrastructure to create and track pKVM instances at EL2 KVM: arm64: Rename 'host_kvm' to 'host_mmu' KVM: arm64: Add hyp_spinlock_t static initializer KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.h KVM: arm64: Add helpers to pin memory shared with the hypervisor at EL2 KVM: arm64: Prevent the donation of no-map pages KVM: arm64: Implement do_donate() helper for donating memory ... Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-11-11KVM: arm64: Don't unnecessarily map host kernel sections at EL2Quentin Perret
We no longer need to map the host's '.rodata' and '.bss' sections in the stage-1 page-table of the pKVM hypervisor at EL2, so remove those mappings and avoid creating any future dependencies at EL2 on host-controlled data structures. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-25-will@kernel.org
2022-11-11KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2Quentin Perret
The pkvm hypervisor at EL2 may need to read the 'kvm_vgic_global_state' variable from the host, for example when saving and restoring the state of the virtual GIC. Explicitly map 'kvm_vgic_global_state' in the stage-1 page-table of the pKVM hypervisor rather than relying on mapping all of the host '.rodata' section. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-24-will@kernel.org
2022-11-11KVM: arm64: Add per-cpu fixmap infrastructure at EL2Quentin Perret
Mapping pages in a guest page-table from within the pKVM hypervisor at EL2 may require cache maintenance to ensure that the initialised page contents is visible even to non-cacheable (e.g. MMU-off) accesses from the guest. In preparation for performing this maintenance at EL2, introduce a per-vCPU fixmap which allows the pKVM hypervisor to map guest pages temporarily into its stage-1 page-table for the purposes of cache maintenance and, in future, poisoning on the reclaim path. The use of a fixmap avoids the need for memory allocation or locking on the map() path. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Co-developed-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-15-will@kernel.org
2022-11-11KVM: arm64: Add infrastructure to create and track pKVM instances at EL2Fuad Tabba
Introduce a global table (and lock) to track pKVM instances at EL2, and provide hypercalls that can be used by the untrusted host to create and destroy pKVM VMs and their vCPUs. pKVM VM/vCPU state is directly accessible only by the trusted hypervisor (EL2). Each pKVM VM is directly associated with an untrusted host KVM instance, and is referenced by the host using an opaque handle. Future patches will provide hypercalls to allow the host to initialize/set/get pKVM VM/vCPU state using the opaque handle. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Co-developed-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> [maz: silence warning on unmap_donated_memory_noclear()] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-13-will@kernel.org
2022-11-11KVM: arm64: Unify identifiers used to distinguish host and hypervisorWill Deacon
The 'pkvm_component_id' enum type provides constants to refer to the host and the hypervisor, yet this information is duplicated by the 'pkvm_hyp_id' constant. Remove the definition of 'pkvm_hyp_id' and move the 'pkvm_component_id' type definition to 'mem_protect.h' so that it can be used outside of the memory protection code, for example when initialising the owner for hypervisor-owned pages. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-6-will@kernel.org
2022-11-11KVM: arm64: Fix-up hyp stage-1 refcounts for all pages mapped at EL2Quentin Perret
In order to allow unmapping arbitrary memory pages from the hypervisor stage-1 page-table, fix-up the initial refcount for pages that have been mapped before the 'vmemmap' array was up and running so that it accurately accounts for all existing hypervisor mappings. This is achieved by traversing the entire hypervisor stage-1 page-table during initialisation of EL2 and updating the corresponding 'struct hyp_page' for each valid mapping. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-5-will@kernel.org
2022-11-11KVM: arm64: Back the hypervisor 'struct hyp_page' array for all memoryQuentin Perret
The EL2 'vmemmap' array in nVHE Protected mode is currently very sparse: only memory pages owned by the hypervisor itself have a matching 'struct hyp_page'. However, as the size of this struct has been reduced significantly since its introduction, it appears that we can now afford to back the vmemmap for all of memory. Having an easily accessible 'struct hyp_page' for every physical page in memory provides the hypervisor with a simple mechanism to store metadata (e.g. a refcount) that wouldn't otherwise fit in the very limited number of software bits available in the host stage-2 page-table entries. This will be used in subsequent patches when pinning host memory pages for use by the hypervisor at EL2. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-4-will@kernel.org
2022-11-10KVM: arm64: Pass mm_ops through the visitor contextOliver Upton
As a prerequisite for getting visitors off of struct kvm_pgtable, pass mm_ops through the visitor context. No functional change intended. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221107215644.1895162-4-oliver.upton@linux.dev
2022-11-10KVM: arm64: Stash observed pte value in visitor contextOliver Upton
Rather than reading the ptep all over the shop, read the ptep once from __kvm_pgtable_visit() and stick it in the visitor context. Reread the ptep after visiting a leaf in case the callback installed a new table underneath. No functional change intended. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221107215644.1895162-3-oliver.upton@linux.dev
2022-11-10KVM: arm64: Combine visitor arguments into a context structureOliver Upton
Passing new arguments by value to the visitor callbacks is extremely inflexible for stuffing new parameters used by only some of the visitors. Use a context structure instead and pass the pointer through to the visitor callback. While at it, redefine the 'flags' parameter to the visitor to contain the bit indicating the phase of the walk. Pass the entire set of flags through the context structure such that the walker can communicate additional state to the visitor callback. No functional change intended. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Ben Gardon <bgardon@google.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221107215644.1895162-2-oliver.upton@linux.dev
2022-04-28KVM: arm64: Add guard pages for pKVM (protected nVHE) hypervisor stackKalesh Singh
Map the stack pages in the flexible private VA range and allocate guard pages below the stack as unbacked VA space. The stack is aligned so that any valid stack address has PAGE_SHIFT bit as 1 - this is used for overflow detection (implemented in a subsequent patch in the series) 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/20220420214317.3303360-5-kaleshsingh@google.com
2021-12-16Merge branch kvm-arm64/pkvm-hyp-sharing into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-hyp-sharing: : . : Series from Quentin Perret, implementing HYP page share/unshare: : : This series implements an unshare hypercall at EL2 in nVHE : protected mode, and makes use of it to unmmap guest-specific : data-structures from EL2 stage-1 during guest tear-down. : Crucially, the implementation of the share and unshare : routines use page refcounts in the host kernel to avoid : accidentally unmapping data-structures that overlap a common : page. : [...] : . KVM: arm64: pkvm: Unshare guest structs during teardown KVM: arm64: Expose unshare hypercall to the host KVM: arm64: Implement do_unshare() helper for unsharing memory KVM: arm64: Implement __pkvm_host_share_hyp() using do_share() KVM: arm64: Implement do_share() helper for sharing memory KVM: arm64: Introduce wrappers for host and hyp spin lock accessors KVM: arm64: Extend pkvm_page_state enumeration to handle absent pages KVM: arm64: pkvm: Refcount the pages shared with EL2 KVM: arm64: Introduce kvm_share_hyp() KVM: arm64: Implement kvm_pgtable_hyp_unmap() at EL2 KVM: arm64: Hook up ->page_count() for hypervisor stage-1 page-table KVM: arm64: Fixup hyp stage-1 refcount KVM: arm64: Refcount hyp stage-1 pgtable pages KVM: arm64: Provide {get,put}_page() stubs for early hyp allocator Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-16KVM: arm64: Hook up ->page_count() for hypervisor stage-1 page-tableWill Deacon
kvm_pgtable_hyp_unmap() relies on the ->page_count() function callback being provided by the memory-management operations for the page-table. Wire up this callback for the hypervisor stage-1 page-table. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211215161232.1480836-5-qperret@google.com
2021-12-16KVM: arm64: Fixup hyp stage-1 refcountQuentin Perret
In nVHE-protected mode, the hyp stage-1 page-table refcount is broken due to the lack of refcount support in the early allocator. Fix-up the refcount in the finalize walker, once the 'hyp_vmemmap' is up and running. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211215161232.1480836-4-qperret@google.com
2021-12-15Merge branch kvm-arm64/pkvm-cleanups-5.17 into kvmarm-master/nextMarc Zyngier
* kvm-arm64/pkvm-cleanups-5.17: : . : pKVM cleanups from Quentin Perret: : : This series is a collection of various fixes and cleanups for KVM/arm64 : when running in nVHE protected mode. The first two patches are real : fixes/improvements, the following two are minor cleanups, and the last : two help satisfy my paranoia so they're certainly optional. : . KVM: arm64: pkvm: Make kvm_host_owns_hyp_mappings() robust to VHE KVM: arm64: pkvm: Stub io map functions KVM: arm64: Make __io_map_base static KVM: arm64: Make the hyp memory pool static KVM: arm64: pkvm: Disable GICv2 support KVM: arm64: pkvm: Fix hyp_pool max order Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-15KVM: arm64: Make the hyp memory pool staticQuentin Perret
The hyp memory pool struct is sized to fit exactly the needs of the hypervisor stage-1 page-table allocator, so it is important it is not used for anything else. As it is currently used only from setup.c, reduce its visibility by marking it static. Signed-off-by: Quentin Perret <qperret@google.com> Reviewed-by: Andrew Walbran <qwandor@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211208152300.2478542-4-qperret@google.com
2021-12-06KVM: arm64: Move host EL1 code out of hyp/ directoryWill Deacon
kvm/hyp/reserved_mem.c contains host code executing at EL1 and is not linked into the hypervisor object. Move the file into kvm/pkvm.c and rework the headers so that the definitions shared between the host and the hypervisor live in asm/kvm_pkvm.h. Signed-off-by: Will Deacon <will@kernel.org> 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/20211202171048.26924-4-will@kernel.org
2021-11-08KVM: arm64: Fix host stage-2 finalizationQuentin Perret
We currently walk the hypervisor stage-1 page-table towards the end of hyp init in nVHE protected mode and adjust the host page ownership attributes in its stage-2 in order to get a consistent state from both point of views. The walk is done on the entire hyp VA space, and expects to only ever find page-level mappings. While this expectation is reasonable in the half of hyp VA space that maps memory with a fixed offset (see the loop in pkvm_create_mappings_locked()), it can be incorrect in the other half where nothing prevents the usage of block mappings. For instance, on systems where memory is physically aligned at an address that happens to maps to a PMD aligned VA in the hyp_vmemmap, kvm_pgtable_hyp_map() will install block mappings when backing the hyp_vmemmap, which will later cause finalize_host_mappings() to fail. Furthermore, it should be noted that all pages backing the hyp_vmemmap are also mapped in the 'fixed offset range' of the hypervisor, which implies that finalize_host_mappings() will walk both aliases and update the host stage-2 attributes twice. The order in which this happens is unpredictable, though, since the hyp VA layout is highly dependent on the position of the idmap page, hence resulting in a fragile mess at best. In order to fix all of this, let's restrict the finalization walk to only cover memory regions in the 'fixed-offset range' of the hyp VA space and nothing else. This not only fixes a correctness issue, but will also result in a slighlty faster hyp initialization overall. Fixes: 2c50166c62ba ("KVM: arm64: Mark host bss and rodata section as shared") Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211108154636.393384-1-qperret@google.com
2021-10-18KVM: arm64: pkvm: Consolidate include filesMarc Zyngier
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
2021-10-11KVM: arm64: Add handlers for protected VM System RegistersFuad Tabba
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
2021-08-11KVM: arm64: Mark host bss and rodata section as sharedQuentin Perret
As the hypervisor maps the host's .bss and .rodata sections in its stage-1, make sure to tag them as shared in hyp and host page-tables. But since the hypervisor relies on the presence of these mappings, we cannot let the host in complete control of the memory regions -- it must not unshare or donate them to another entity for example. To prevent this, let's transfer the ownership of those ranges to the hypervisor itself, and share the pages back with the host. Signed-off-by: Quentin Perret <qperret@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210809152448.1810400-18-qperret@google.com
2021-06-18Merge branch arm64/for-next/caches into kvmarm-master/nextMarc Zyngier
arm64 cache management function cleanup from Fuad Tabba, shared with the arm64 tree. * arm64/for-next/caches: arm64: Rename arm64-internal cache maintenance functions arm64: Fix cache maintenance function comments arm64: sync_icache_aliases to take end parameter instead of size arm64: __clean_dcache_area_pou to take end parameter instead of size arm64: __clean_dcache_area_pop to take end parameter instead of size arm64: __clean_dcache_area_poc to take end parameter instead of size arm64: __flush_dcache_area to take end parameter instead of size arm64: dcache_by_line_op to take end parameter instead of size arm64: __inval_dcache_area to take end parameter instead of size arm64: Fix comments to refer to correct function __flush_icache_range arm64: Move documentation of dcache_by_line_op arm64: assembler: remove user_alt arm64: Downgrade flush_icache_range to invalidate arm64: Do not enable uaccess for invalidate_icache_range arm64: Do not enable uaccess for flush_icache_range arm64: Apply errata to swsusp_arch_suspend_exit arm64: assembler: add conditional cache fixups arm64: assembler: replace `kaddr` with `addr` Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-06-11KVM: arm64: Remove hyp_pool pointer from struct hyp_pageQuentin Perret
Each struct hyp_page currently contains a pointer to a hyp_pool struct where the page should be freed if its refcount reaches 0. However, this information can always be inferred from the context in the EL2 code, so drop the pointer to save a few bytes in the vmemmap. Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210608114518.748712-6-qperret@google.com
2021-06-11KVM: arm64: Unify MMIO and mem host stage-2 poolsQuentin Perret
We currently maintain two separate memory pools for the host stage-2, one for pages used in the page-table when mapping memory regions, and the other to map MMIO regions. The former is large enough to map all of memory with page granularity and the latter can cover an arbitrary portion of IPA space, but allows to 'recycle' pages. However, this split makes accounting difficult to manage as pages at intermediate levels of the page-table may be used to map both memory and MMIO regions. Simplify the scheme by merging both pools into one. This means we can now hit the -ENOMEM case in the memory abort path, but we're still guaranteed forward-progress in the worst case by unmapping MMIO regions. On the plus side this also means we can usually map a lot more MMIO space at once if memory ranges happen to be mapped with block mappings. Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210608114518.748712-5-qperret@google.com
2021-05-25arm64: Rename arm64-internal cache maintenance functionsFuad Tabba
Although naming across the codebase isn't that consistent, it tends to follow certain patterns. Moreover, the term "flush" isn't defined in the Arm Architecture reference manual, and might be interpreted to mean clean, invalidate, or both for a cache. Rename arm64-internal functions to make the naming internally consistent, as well as making it consistent with the Arm ARM, by specifying whether it applies to the instruction, data, or both caches, whether the operation is a clean, invalidate, or both. Also specify which point the operation applies to, i.e., to the point of unification (PoU), coherency (PoC), or persistence (PoP). This commit applies the following sed transformation to all files under arch/arm64: "s/\b__flush_cache_range\b/caches_clean_inval_pou_macro/g;"\ "s/\b__flush_icache_range\b/caches_clean_inval_pou/g;"\ "s/\binvalidate_icache_range\b/icache_inval_pou/g;"\ "s/\b__flush_dcache_area\b/dcache_clean_inval_poc/g;"\ "s/\b__inval_dcache_area\b/dcache_inval_poc/g;"\ "s/__clean_dcache_area_poc\b/dcache_clean_poc/g;"\ "s/\b__clean_dcache_area_pop\b/dcache_clean_pop/g;"\ "s/\b__clean_dcache_area_pou\b/dcache_clean_pou/g;"\ "s/\b__flush_cache_user_range\b/caches_clean_inval_user_pou/g;"\ "s/\b__flush_icache_all\b/icache_inval_all_pou/g;" Note that __clean_dcache_area_poc is deliberately missing a word boundary check at the beginning in order to match the efistub symbols in image-vars.h. Also note that, despite its name, __flush_icache_range operates on both instruction and data caches. The name change here reflects that. No functional change intended. Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20210524083001.2586635-19-tabba@google.com Signed-off-by: Will Deacon <will@kernel.org>
2021-05-25arm64: __flush_dcache_area to take end parameter instead of sizeFuad Tabba
To be consistent with other functions with similar names and functionality in cacheflush.h, cache.S, and cachetlb.rst, change to specify the range in terms of start and end, as opposed to start and size. No functional change intended. Reported-by: Will Deacon <will@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Fuad Tabba <tabba@google.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20210524083001.2586635-13-tabba@google.com Signed-off-by: Will Deacon <will@kernel.org>
2021-05-15KVM: arm64: Mark pkvm_pgtable_mm_ops staticQuentin Perret
It is not used outside of setup.c, mark it static. Fixes:f320bc742bc2 ("KVM: arm64: Prepare the creation of s1 mappings at EL2") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210514085640.3917886-2-qperret@google.com