[PATCH v2 00/35] KVM: arm64: Add support for protected guest memory with pKVM

Will Deacon
2026-01-19T12:46:53Z

Hi folks,

It's back and it's even bigger than before!

Although the first patch has been picked up as a fix (thanks, Oliver),
review feedback has resulted in some additional patches being included
in the series. If you'd like to see the first version, it's available
here:

https://lore.kernel.org/kvmarm/20260105154939.11041-1-will@kernel.org/

Changes since v1 include:

* Change hypercall order so that pKVM-specific calls are in their own
range
* Make 'pkvm_handle_t' a u16 and check its size at compile-time
* Rework pte annotations to take a 4-bit type field
* Fix a memory leak on the kvm_arch_init_vm() failure path
* Pass KVM_PGTABLE_WALK_IGNORE_EAGAIN when mapping into the host idmap
* Avoid host annotation when reclaiming guest pages
* Re-instate guest pte metadata when unsharing a page
* Extend selftests to cover guest share and unshare hypercalls
* Drop broken MMU notifier changes
* Documentation tweaks

As before, patches are based on v6.19-rc4 and are also available at:

https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=kvm/protected-memory

All feedback welcome.

Cheers,

Will

Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Mostafa Saleh <smostafa@google.com>

--->8

Fuad Tabba (1):
KVM: arm64: Expose self-hosted debug regs as RAZ/WI for protected
guests

Quentin Perret (2):
KVM: arm64: Refactor enter_exception64()
KVM: arm64: Inject SIGSEGV on illegal accesses

Will Deacon (32):
KVM: arm64: Invert KVM_PGTABLE_WALK_HANDLE_FAULT to fix pKVM walkers
KVM: arm64: Don't leak stage-2 page-table if VM fails to init under
pKVM
KVM: arm64: Move handle check into pkvm_pgtable_stage2_destroy_range()
KVM: arm64: Rename __pkvm_pgtable_stage2_unmap()
KVM: arm64: Don't advertise unsupported features for protected guests
KVM: arm64: Remove is_protected_kvm_enabled() checks from hypercalls
KVM: arm64: Ignore MMU notifier callbacks for protected VMs
KVM: arm64: Prevent unsupported memslot operations on protected VMs
KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host
KVM: arm64: Split teardown hypercall into two phases
KVM: arm64: Introduce __pkvm_host_donate_guest()
KVM: arm64: Hook up donation hypercall to pkvm_pgtable_stage2_map()
KVM: arm64: Handle aborts from protected VMs
KVM: arm64: Introduce __pkvm_reclaim_dying_guest_page()
KVM: arm64: Hook up reclaim hypercall to pkvm_pgtable_stage2_destroy()
KVM: arm64: Avoid pointless annotation when mapping host-owned pages
KVM: arm64: Generalise kvm_pgtable_stage2_set_owner()
KVM: arm64: Introduce host_stage2_set_owner_metadata_locked()
KVM: arm64: Change 'pkvm_handle_t' to u16
KVM: arm64: Annotate guest donations with handle and gfn in host
stage-2
KVM: arm64: Introduce hypercall to force reclaim of a protected page
KVM: arm64: Reclaim faulting page from pKVM in spurious fault handler
KVM: arm64: Return -EFAULT from VCPU_RUN on access to a poisoned pte
KVM: arm64: Add hvc handler at EL2 for hypercalls from protected VMs
KVM: arm64: Implement the MEM_SHARE hypercall for protected VMs
KVM: arm64: Implement the MEM_UNSHARE hypercall for protected VMs
KVM: arm64: Allow userspace to create protected VMs when pKVM is
enabled
KVM: arm64: Add some initial documentation for pKVM
KVM: arm64: Extend pKVM page ownership selftests to cover guest
donation
KVM: arm64: Register 'selftest_vm' in the VM table
KVM: arm64: Extend pKVM page ownership selftests to cover forced
reclaim
KVM: arm64: Extend pKVM page ownership selftests to cover guest hvcs

.../admin-guide/kernel-parameters.txt | 4 +-
Documentation/virt/kvm/arm/index.rst | 1 +
Documentation/virt/kvm/arm/pkvm.rst | 103 +++
arch/arm64/include/asm/kvm_asm.h | 27 +-
arch/arm64/include/asm/kvm_emulate.h | 5 +
arch/arm64/include/asm/kvm_host.h | 9 +-
arch/arm64/include/asm/kvm_pgtable.h | 51 +-
arch/arm64/include/asm/kvm_pkvm.h | 4 +-
arch/arm64/include/asm/virt.h | 6 +
arch/arm64/kvm/Kconfig | 10 +
arch/arm64/kvm/arm.c | 12 +-
arch/arm64/kvm/hyp/exception.c | 100 +--
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 9 +
arch/arm64/kvm/hyp/include/nvhe/memory.h | 6 +
arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 7 +-
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 125 ++--
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 595 ++++++++++++++++--
arch/arm64/kvm/hyp/nvhe/pkvm.c | 224 ++++++-
arch/arm64/kvm/hyp/nvhe/switch.c | 1 +
arch/arm64/kvm/hyp/nvhe/sys_regs.c | 8 +
arch/arm64/kvm/hyp/pgtable.c | 38 +-
arch/arm64/kvm/mmu.c | 122 +++-
arch/arm64/kvm/pkvm.c | 149 ++++-
arch/arm64/mm/fault.c | 31 +-
include/uapi/linux/kvm.h | 5 +
25 files changed, 1405 insertions(+), 247 deletions(-)
create mode 100644 Documentation/virt/kvm/arm/pkvm.rst

--
2.52.0.457.g6b5491de43-goog