Re: [PATCH v2 0/3] KVM: arm64: Fixes for resolving the fault IPA

[Marc Zyngier <maz@kernel.org>]

On Wed, 02 Apr 2025 21:17:22 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> KVM's heuristics for determining the fault IPA are a bit shaky and don't
> necessarily align with the letter of the architecture. On top of that,
> HPFAR_EL2 is UNKNOWN if an SEA occurred during a table walk. Re-walking
> the page tables will replay the SEA at EL2, becoming a panic in the hyp.
> 
> v1: https://lore.kernel.org/kvmarm/20250401224234.2906739-1-oliver.upton@linux.dev/
> 
> v1 -> v2 (addressed Marc's feedback):
>  - Drop section reference in favor of the rule for HPFAR_EL2 validity
>  - Fold test for Address size fault into helper, reuse existing
>    definitions
>  - Get rid of 'magic' shift for transforming FIPA field to an actual IPA
>  - Add BUG_ON() to handle_host_mem_abort() if we fail to resolve the
>    fault IPA.
> 
> Oliver Upton (3):
>   KVM: arm64: Only read HPFAR_EL2 when value is architecturally valid
>   arm64: Convert HPFAR_EL2 to sysreg table
>   KVM: arm64: Don't translate FAR if invalid/unsafe
> 
>  arch/arm64/include/asm/esr.h           | 44 +++++++++++++++-
>  arch/arm64/include/asm/kvm_emulate.h   |  7 ++-
>  arch/arm64/include/asm/kvm_ras.h       |  2 +-
>  arch/arm64/kvm/hyp/include/hyp/fault.h | 70 ++++++++++++++++++--------
>  arch/arm64/kvm/hyp/nvhe/mem_protect.c  |  9 +++-
>  arch/arm64/kvm/mmu.c                   | 31 +++++++-----
>  arch/arm64/tools/sysreg                |  7 +++
>  7 files changed, 131 insertions(+), 39 deletions(-)
> 
> 
> base-commit: 369c0122682c4468a69f2454614eded71c5348f3

My comment on patch #1 notwithstanding, this looks pretty good.

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

	M.

-- 
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