Re: [PATCH 00/16] KVM: arm64: selftests: Tests for protected VMs

[Joey Gouly <joey.gouly@arm.com>]

On Wed, Nov 04, 2026 at 08:48:26AM +0000, Fuad Tabba wrote:
> Hi folks,
> 
> This series adds selftests for protected VMs. A test skips on a host
> without pKVM, and so does any case where the host doesn't have the
> required feature, e.g., PtrAuth, SVE or hugetlb pages.
> 
> A couple of points:
> 
> - Each area gets its own test rather than cases folded into existing
>   tests such as psci_test, hypercalls, set_id_regs, etc. A protected
>   guest requires its own boot path, and has to share the ucall pool
>   before its first ucall. On top of that, a protected guest gets the
>   opposite result for many of those tests' checks.
> 
> - pkvm_exceptions skips its breakpoint, watchpoint and single-step cases
>   while a protected guest's ID_AA64DFR0_EL1.DebugVer is 0. pkvm_id_regs
>   reads the same field to choose between the hidden and the exposed
>   debug view. With the patch that adds self-hosted debug to protected
>   guests [1], both tests run the debug cases with no change.
> 
> The series is structured as follows:
> 
>   01:     external_aborts: an abort injected before a vCPU's first run.
>   02-04:  Generic selftest changes: creating a protected VM, the pKVM
>           function IDs and the ucall pool's address.
>   05-06:  Protected-VM library: boot trampoline and helpers.
>   07-16:  The tests, one per area.
> 
> Based on Linux 7.4-rc1 (6628e7d4c6b25).

Hi!

I started to also write some realm tests a bit, you can check it out
here:
	https://gitlab.arm.com/linux-arm/linux-jg/-/tree/cca-kselftest

It's WIP/prototype, but it may be good to have some sharing, if
possible.
For example I also added a 'pre-boot' stub, which looks like your
pvm-entry.S:

	https://gitlab.arm.com/linux-arm/linux-jg/-/commit/cd3ae35d89974b02b7051a0c45cc68b4df8f9d3e

However I extracted the registers needed for the stub like this:

	https://gitlab.arm.com/linux-arm/linux-jg/-/commit/f559d5b61fa1a37e2d7b23704bd367e079cf8eae

This is because the current Realm branch I'm working on top of rejects
writes to those system registers (TCR_EL1, CPACR_EL1 etc). Which is why
I had to modify these functions, along with __aarch64_vcpu_add() and
some others.

I'm not sure how much there is to gain by sharing overall, but good to
bring it up early!

Thanks,
Joey

> 
> Cheers,
> /fuad
> 
> [1] https://lore.kernel.org/all/20261102093950.2922035-1-fuad.tabba@linux.dev/
> 
> Fuad Tabba (16):
>   KVM: arm64: selftests: Inject an abort before a vCPU's first run
>   KVM: selftests: Allow arm64 tests to create protected VMs
>   tools: arm-smccc: Add the pKVM memory sharing function IDs
>   KVM: selftests: Export the ucall pool's guest physical address
>   KVM: arm64: selftests: Add protected-VM boot trampoline
>   KVM: arm64: selftests: Add protected-VM library helpers
>   KVM: arm64: selftests: Add pkvm_host_abi host-interface test
>   KVM: arm64: selftests: Add pkvm_psci multi-vCPU PSCI test
>   KVM: arm64: selftests: Add pkvm_mem_share hypercall test
>   KVM: arm64: selftests: Add pkvm_smccc hypercall test
>   KVM: arm64: selftests: Add pkvm_id_regs register and trap test
>   KVM: arm64: selftests: Add pkvm_vcpu_regs register-state test
>   KVM: arm64: selftests: Add pkvm_irq interrupt test
>   KVM: arm64: selftests: Add pkvm_isolation host-access test
>   KVM: arm64: selftests: Add pkvm_lifecycle teardown test
>   KVM: arm64: selftests: Add pkvm_exceptions debug and SError test
> 
>  tools/include/linux/arm-smccc.h               |  22 +
>  tools/testing/selftests/kvm/Makefile.kvm      |  12 +
>  .../selftests/kvm/arm64/external_aborts.c     |  21 +
>  .../selftests/kvm/arm64/pkvm_exceptions.c     | 261 ++++++++
>  .../selftests/kvm/arm64/pkvm_host_abi.c       | 428 ++++++++++++
>  .../selftests/kvm/arm64/pkvm_id_regs.c        | 306 +++++++++
>  tools/testing/selftests/kvm/arm64/pkvm_irq.c  | 268 ++++++++
>  .../selftests/kvm/arm64/pkvm_isolation.c      | 225 +++++++
>  .../selftests/kvm/arm64/pkvm_lifecycle.c      | 110 +++
>  .../selftests/kvm/arm64/pkvm_mem_share.c      | 394 +++++++++++
>  tools/testing/selftests/kvm/arm64/pkvm_psci.c | 632 ++++++++++++++++++
>  .../testing/selftests/kvm/arm64/pkvm_smccc.c  | 117 ++++
>  .../selftests/kvm/arm64/pkvm_vcpu_regs.c      | 221 ++++++
>  .../selftests/kvm/include/arm64/pkvm.h        |  74 ++
>  .../selftests/kvm/include/ucall_common.h      |   1 +
>  tools/testing/selftests/kvm/lib/arm64/pkvm.c  | 245 +++++++
>  .../selftests/kvm/lib/arm64/pvm-entry.S       |  58 ++
>  tools/testing/selftests/kvm/lib/kvm_util.c    |   5 +-
>  .../testing/selftests/kvm/lib/ucall_common.c  |   9 +-
>  19 files changed, 3406 insertions(+), 3 deletions(-)
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_exceptions.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_host_abi.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_id_regs.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_irq.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_isolation.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_lifecycle.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_mem_share.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_psci.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_smccc.c
>  create mode 100644 tools/testing/selftests/kvm/arm64/pkvm_vcpu_regs.c
>  create mode 100644 tools/testing/selftests/kvm/include/arm64/pkvm.h
>  create mode 100644 tools/testing/selftests/kvm/lib/arm64/pkvm.c
>  create mode 100644 tools/testing/selftests/kvm/lib/arm64/pvm-entry.S
> 
> 
> base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4
> -- 
> 2.47.3
>