Hi Mostafa,
On Wed, 23 Oct 2024 18:12:43 +0100,
Mostafa Saleh <smostafa@xxxxxxxxxx> wrote:
>
> Commit 5053c3f0519c ("KVM: arm64: Use hVHE in pKVM by default on CPUs with
> VHE support") modified the behaviour of "kvm-arm.mode=protected" without
> the updating the kernel parameters doc.
>
> Update it to match the current implementation.
>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Marc Zyngier <maz@xxxxxxxxxx>
>
> Signed-off-by: Mostafa Saleh <smostafa@xxxxxxxxxx>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index bb48ae24ae69..59a0dd7e2de6 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2723,8 +2723,12 @@
> nvhe: Standard nVHE-based mode, without support for
> protected guests.
>
> - protected: nVHE-based mode with support for guests whose
> + protected: hVHE-based mode with support for guests whose
> state is kept private from the host.
> + In case hVHE is not supported in hardware, it will
nit: it is VHE that is supported or not, hVHE is only a SW concept.
> + boot with protected nVHE.
> + nVHE protected mode can still be forced on VHE systems
> + using "kvm_arm.mode=protected arm64_sw.hvhe=0 id_aa64mmfr1.vh=0"
This opens another question: none of the arm_sw.*, nor any of the
id_aa64* parameters are described (basically, anything that's in
arch/arm64/kernel/pi/id_override.c). What should we do about these?
>
> nested: VHE-based mode with support for nested
> virtualization. Requires at least ARMv8.3
Huh, another nit to fix. We only support nested with ARMv8.4 (with
FEAT_NV2), as the ARMv8.3 version (the original FEAT_NV) is too ugly
for words.
Mind addressing this?
Thanks!
M.
--
Without deviation from the norm, progress is not possible.
