KVM: arm64: Add support for protected guest memory with pKVM

Hi again, folks,

Here's v4 of the pKVM protected memory patches previously posted here:

  v1: https://lore.kernel.org/kvmarm/20260105154939.11041-1-wil...
  v2: https://lore.kernel.org/kvmarm/20260119124629.2563-1-will...
  v3: https://lore.kernel.org/r/20260305144351.17071-1-will@ker...

Changes since v3 include:

  * Rebased onto v7.0-rc4
  * Remove unused PKVM_ID_FFA
  * Make ARM_PKVM_GUEST depend on DMA_RESTRICTED_POOL
  * Use FAR_TO_FIPA_OFFSET() instead of open-coding it
  * Remove PROTECTED_VM_UAPI config option and update documentation

As before, I've pushed an updated branch with this series:

  https://git.kernel.org/pub/scm/linux/kernel/git/will/linu...

and the kvmtool patches are available at:

  https://git.kernel.org/pub/scm/linux/kernel/git/will/kvmt...

I fully expect to send a v5, as this is the first time Sashiko has had
a chance to chew on this and I'm expecting a roasting.

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>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>

--->8

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

Quentin Perret (1):
  KVM: arm64: Inject SIGSEGV on illegal accesses

Will Deacon (36):
  KVM: arm64: Remove unused PKVM_ID_FFA definition
  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: Factor out pKVM host exception injection logic
  KVM: arm64: Support translation faults in inject_host_exception()
  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
  KVM: arm64: Rename PKVM_PAGE_STATE_MASK
  drivers/virt: pkvm: Add Kconfig dependency on DMA_RESTRICTED_POOL

 .../admin-guide/kernel-parameters.txt         |   4 +-
 Documentation/virt/kvm/arm/index.rst          |   1 +
 Documentation/virt/kvm/arm/pkvm.rst           | 106 ++++
 arch/arm64/include/asm/kvm_asm.h              |  31 +-
 arch/arm64/include/asm/kvm_host.h             |   9 +-
 arch/arm64/include/asm/kvm_pgtable.h          |  45 +-
 arch/arm64/include/asm/kvm_pkvm.h             |   4 +-
 arch/arm64/include/asm/virt.h                 |   9 +
 arch/arm64/kvm/arm.c                          |  12 +-
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  10 +-
 arch/arm64/kvm/hyp/include/nvhe/memory.h      |  12 +-
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h        |   7 +-
 .../arm64/kvm/hyp/include/nvhe/trap_handler.h |   2 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 184 +++---
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 585 ++++++++++++++++--
 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                  |  33 +-
 arch/arm64/kvm/mmu.c                          | 114 +++-
 arch/arm64/kvm/pkvm.c                         | 151 ++++-
 arch/arm64/mm/fault.c                         |  33 +-
 drivers/virt/coco/pkvm-guest/Kconfig          |   2 +-
 include/uapi/linux/kvm.h                      |   5 +
 24 files changed, 1365 insertions(+), 227 deletions(-)
 create mode 100644 Documentation/virt/kvm/arm/pkvm.rst

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2.53.0.1018.g2bb0e51243-goog