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SubjectRe: [PATCH v3 18/20] kvm: arm64: Add support for handling 52bit IPA
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On 29/06/18 12:15, Suzuki K Poulose wrote:
> Add support for handling the 52bit IPA. 52bit IPA
> support needs changes to the following :
>
> 1) Page-table entries - We use kernel page table helpers for setting
> up the stage2. Hence we don't explicit changes here
>
> 2) VTTBR:BADDR - This is already supported with :
> commit 529c4b05a3cb2f324aa ("arm64: handle 52-bit addresses in TTBR")
>
> 3) VGIC support for 52bit: Supported with a patch in this series.
>
> That leaves us with the handling for PAR and HPAR. This patch adds

HPFAR?

> support for handling the 52bit addresses in PAR and HPFAR,
> which are used while handling the permission faults in stage1.

Overall, this is a pretty confusing commit message. Can you just call it:

KVM/arm64: Add 52bit support for PAR to HPFAR conversion

and just describe that it now uses PHYS_MASK_SHIFT instead of a
hardcoded constant?

>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Kristina Martsenko <kristina.martsenko@arm.com>
> Cc: Christoffer Dall <cdall@kernel.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arch/arm64/include/asm/kvm_arm.h | 7 +++++++
> arch/arm64/kvm/hyp/switch.c | 2 +-
> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 2e90942..cb6a2ee 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -301,6 +301,13 @@
>
> /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
> #define HPFAR_MASK (~UL(0xf))
> +/*
> + * We have
> + * PAR [PA_Shift - 1 : 12] = PA [PA_Shift - 1 : 12]
> + * HPFAR [PA_Shift - 9 : 4] = FIPA [PA_Shift - 1 : 12]
> + */
> +#define PAR_TO_HPFAR(par) \
> + (((par) & GENMASK_ULL(PHYS_MASK_SHIFT - 1, 12)) >> 8)
>
> #define kvm_arm_exception_type \
> {0, "IRQ" }, \
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index 355fb25..fb66320 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -260,7 +260,7 @@ static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
> return false; /* Translation failed, back to guest */
>
> /* Convert PAR to HPFAR format */
> - *hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4;
> + *hpfar = PAR_TO_HPFAR(tmp);
> return true;
> }
>
>

Otherwise:

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

M.
--
Jazz is not dead. It just smells funny...

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