Re: [PATCH v2 0/7] Fix setting SVE and SME traps in (h)VHE

[Marc Zyngier <maz@kernel.org>]

Hey Fuad,

On Fri, 21 Jul 2023 10:51:37 +0100,
Fuad Tabba <tabba@google.com> wrote:
> 
> Hi,
> 
> Changes from V1:
> - Expanded the cover letter to clarify the reasoning behind being
> consistent in writing to the architectural trap register based on
> the KVM mode (Marc)
> - Factored out the code for checking E2H into a macro (Oliver)
> - Factored out the code that selects which register to write to
> into a function (Oliver)
> 
> The (re)setting and disabling of SVE/SME trap handling (mostly)
> done for the hVHE work [*] misses a couple of cases.
> 
> This patch series ensures that these traps are disabled on setup
> and reset. Moreover, it makes the code consistent in using
> CPACR_EL1 or CPTR_EL2, depending on the mode.
> 
> CPACR_EL1 aliases to CPTR_EL2 when HCR_EL2.E2H == 1, but by being
> consistent we don't need to issue a synchronisation when
> alternating between one or the other accessor. Moreover, when
> running hVHE under NV, we don't trap unnecessarily on accessing
> CPTR_EL2, while CPACR_EL1 can be used directly without any trap.
> 
> Based on Linux 6.5-rc2.
> 
> Cheers,
> /fuad
> 
> [*] https://lore.kernel.org/all/20230609162200.2024064-1-maz@kernel.org/
> 
> Fuad Tabba (7):
>   KVM: arm64: Factor out code for checking E2H into a macro
>   KVM: arm64: Use the appropriate feature trap register for SVE at EL2
>     setup
>   KVM: arm64: Disable SME traps for (h)VHE at setup
>   KVM: arm64: Helper to write to appropriate feature trap register based
>     on mode
>   KVM: arm64: Use the appropriate feature trap register when activating
>     traps
>   KVM: arm64: Fix resetting SVE trap values on reset for hVHE
>   KVM: arm64: Fix resetting SME trap values on reset for (h)VHE
> 
>  arch/arm64/include/asm/el2_setup.h   | 44 ++++++++++++++++++----------
>  arch/arm64/include/asm/kvm_emulate.h | 21 ++++++++++---
>  arch/arm64/kvm/hyp/nvhe/switch.c     |  2 +-
>  3 files changed, 47 insertions(+), 20 deletions(-)

Thanks again for fixing this, and going the extra mile on the cleanup
front. FWIW,

Reviewed-by: Marc Zyngier <maz@kernel.org>

	     M.

-- 
Without deviation from the norm, progress is not possible.