[PATCH 3/3] arm64: Add missing ISB after invalidating TLB in enter_vhe

[Mark Rutland]

On Wed, Feb 24, 2021 at 09:37:38AM +0000, Marc Zyngier wrote:
> Although there has been a bit of back and forth on the subject,
> it appears that invalidating TLBs requires an ISB instruction
> after the TLBI/DSB sequence, as documented in d0b7a302d58a
> ("Revert "arm64: Remove unnecessary ISBs from set_{pte,pmd,pud}"").
> 
> Add the missing ISB in enter_vhe(), just in case.
> 
> Fixes: f359182291c7 ("arm64: Provide an 'upgrade to VHE' stub hypercall")
> Suggested-by: Will Deacon <will at kernel.org>
> Signed-off-by: Marc Zyngier <maz at kernel.org>

Same comment as for patch 2; with the commit message similarly updated:

Acked-by: Mark Rutland <mark.rutland at arm.com>

Thanks,
Mark.

> ---
>  arch/arm64/kernel/hyp-stub.S | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
> index ae56787ea7c1..5eccbd62fec8 100644
> --- a/arch/arm64/kernel/hyp-stub.S
> +++ b/arch/arm64/kernel/hyp-stub.S
> @@ -152,6 +152,7 @@ SYM_CODE_START_LOCAL(enter_vhe)
>  	// Invalidate TLBs before enabling the MMU
>  	tlbi	vmalle1
>  	dsb	nsh
> +	isb
>  
>  	// Enable the EL2 S1 MMU, as set up from EL1
>  	mrs_s	x0, SYS_SCTLR_EL12
> -- 
> 2.29.2
>