Re: [PATCH 3/3] KVM: arm64: Use TLBI_TTL_UNKNOWN in __kvm_tlb_flush_vmid_range()

[Ryan Roberts <ryan.roberts@arm.com>]

On 25/03/2024 18:51, Will Deacon wrote:
> Commit c910f2b65518 ("arm64/mm: Update tlb invalidation routines for
> FEAT_LPA2") updated the __tlbi_level() macro to take the target level
> as an argument, with TLBI_TTL_UNKNOWN (rather than 0) indicating that
> the caller cannot provide level information. Unfortunately, the two
> implementations of __kvm_tlb_flush_vmid_range() were not updated and so
> now ask for an level 0 invalidation if FEAT_LPA2 is implemented.

Ouch, sorry about this! I remember rebasing my change onto the KVM tlbi range
changes and having a few conflicts. Obviously I didn't do a good enough job of
reviewing the result and missed this new user.

> 
> Fix the problem by passing TLBI_TTL_UNKNOWN instead of 0 as the level
> argument to __flush_s2_tlb_range_op() in __kvm_tlb_flush_vmid_range().
> 
> Cc: Ryan Roberts <ryan.roberts@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Oliver Upton <oliver.upton@linux.dev>
> Cc: Marc Zyngier <maz@kernel.org>
> Fixes: c910f2b65518 ("arm64/mm: Update tlb invalidation routines for FEAT_LPA2")
> Signed-off-by: Will Deacon <will@kernel.org>

Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>

> ---
>  arch/arm64/kvm/hyp/nvhe/tlb.c | 3 ++-
>  arch/arm64/kvm/hyp/vhe/tlb.c  | 3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c
> index a60fb13e2192..2fc68da4036d 100644
> --- a/arch/arm64/kvm/hyp/nvhe/tlb.c
> +++ b/arch/arm64/kvm/hyp/nvhe/tlb.c
> @@ -154,7 +154,8 @@ void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
>  	/* Switch to requested VMID */
>  	__tlb_switch_to_guest(mmu, &cxt, false);
>  
> -	__flush_s2_tlb_range_op(ipas2e1is, start, pages, stride, 0);
> +	__flush_s2_tlb_range_op(ipas2e1is, start, pages, stride,
> +				TLBI_TTL_UNKNOWN);
>  
>  	dsb(ish);
>  	__tlbi(vmalle1is);
> diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c
> index b32e2940df7d..1a60b95381e8 100644
> --- a/arch/arm64/kvm/hyp/vhe/tlb.c
> +++ b/arch/arm64/kvm/hyp/vhe/tlb.c
> @@ -171,7 +171,8 @@ void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
>  	/* Switch to requested VMID */
>  	__tlb_switch_to_guest(mmu, &cxt);
>  
> -	__flush_s2_tlb_range_op(ipas2e1is, start, pages, stride, 0);
> +	__flush_s2_tlb_range_op(ipas2e1is, start, pages, stride,
> +				TLBI_TTL_UNKNOWN);
>  
>  	dsb(ish);
>  	__tlbi(vmalle1is);