Re: [PATCH v3 01/17] KVM: arm64: Drop is_kernel_in_hyp_mode() from __invalidate_icache_guest_page()

[Shaoqin Huang <shahuang@redhat.com>]

On 6/10/23 00:21, Marc Zyngier wrote:
> It is pretty obvious that is_kernel_in_hyp_mode() doesn't make much
> sense in the hypervisor part of KVM, and should be reserved to the
> kernel side.
> 
> However, mem_protect.c::invalidate_icache_guest_page() calls into
> __invalidate_icache_guest_page(), which uses is_kernel_in_hyp_mode().
> Given that this is part of the pKVM side of the hypervisor, this
> helper can only return true.
> 
> Nothing goes really bad, but __invalidate_icache_guest_page() could
> spell out what the actual check is: we cannot invalidate the cache
> if the i-cache is VPIPT and we're running at EL1.
> 
> Drop the is_kernel_in_hyp_mode() check for an explicit check against
> CurrentEL being EL1 or not.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> ---
>   arch/arm64/include/asm/kvm_mmu.h | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
> index 27e63c111f78..c8113b931263 100644
> --- a/arch/arm64/include/asm/kvm_mmu.h
> +++ b/arch/arm64/include/asm/kvm_mmu.h
> @@ -227,7 +227,8 @@ static inline void __invalidate_icache_guest_page(void *va, size_t size)
>   	if (icache_is_aliasing()) {
>   		/* any kind of VIPT cache */
>   		icache_inval_all_pou();
> -	} else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) {
> +	} else if (read_sysreg(CurrentEL) != CurrentEL_EL1 ||
> +		   !icache_is_vpipt()) {
>   		/* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */
>   		icache_inval_pou((unsigned long)va, (unsigned long)va + size);
>   	}

-- 
Shaoqin


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel