[PATCH v2 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall

Jing Zhang jingzhangos at google.com
Tue Jan 5 17:58:01 EST 2021


On Mon, Jan 4, 2021 at 8:20 AM Marc Zyngier <maz at kernel.org> wrote:
>
> For completeness, let's document the HVC_VHE_RESTART stub.
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  Documentation/virt/kvm/arm/hyp-abi.rst | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/virt/kvm/arm/hyp-abi.rst b/Documentation/virt/kvm/arm/hyp-abi.rst
> index 83cadd8186fa..3961c529769b 100644
> --- a/Documentation/virt/kvm/arm/hyp-abi.rst
> +++ b/Documentation/virt/kvm/arm/hyp-abi.rst
> @@ -58,6 +58,15 @@ these functions (see arch/arm{,64}/include/asm/virt.h):
>    into place (arm64 only), and jump to the restart address while at HYP/EL2.
>    This hypercall is not expected to return to its caller.
>
> +* ::
> +
> +    x0 = HVC_VHE_RESTART (arm64 only)
> +
> +  Attempt to upgrade the kernel's exception level from EL1 to EL2 by enabling
> +  the VHE mode. This is conditionned by the CPU supporting VHE, the EL2 MMU
Typo: conditionned -> conditioned
> +  being off, and VHE not being disabled by any other mean (comment line option,
> +  for example).
> +
>  Any other value of r0/x0 triggers a hypervisor-specific handling,
>  which is not documented here.
>
> --
> 2.29.2
>
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