Re: [PATCH 4/4] KVM: selftests: aarch64: Test read-only PT memory regions

[Oliver Upton <oliver.upton@linux.dev>]

On Tue, Jan 10, 2023 at 02:24:32AM +0000, Ricardo Koller wrote:
> Extend the read-only memslot tests in page_fault_test to test read-only PT
> (Page table) memslots. Note that this was not allowed before commit "KVM:
> arm64: Fix handling of S1PTW S2 fault on RO memslots" as all S1PTW faults
> were treated as writes which resulted in an (unrecoverable) exception
> inside the guest.

Do we need an additional test that the guest gets nuked if TCR_EL1.HA =
0b1 and AF is clear in one of the stage-1 PTEs?

> Signed-off-by: Ricardo Koller <ricarkol@google.com>
> ---
>  .../selftests/kvm/aarch64/page_fault_test.c        | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> index 2e2178a7d0d8..2f81d68e876c 100644
> --- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> +++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> @@ -831,6 +831,7 @@ static void help(char *name)
>  {										\
>  	.name			= SCAT3(ro_memslot, _access, _with_af),		\

Does the '_with_af' actually belong here? The macro doesn't take such a
parameter. AFAICT the access flag is already set in all S1 PTEs for this
case and TCR_EL1.HA = 0b0.

>  	.data_memslot_flags	= KVM_MEM_READONLY,				\
> +	.pt_memslot_flags	= KVM_MEM_READONLY,				\
>  	.guest_prepare		= { _PREPARE(_access) },			\
>  	.guest_test		= _access,					\
>  	.mmio_handler		= _mmio_handler,				\

--
Thanks,
Oliver