From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Wed, 7 Nov 2018 21:59:27 +0000
Subject: [PATCH 6/7] arm64: Do not apply vector harderning for hyp
 entries from EL2
In-Reply-To: <1537970184-44348-7-git-send-email-julien.thierry@arm.com>
References: <1537970184-44348-1-git-send-email-julien.thierry@arm.com>
 <1537970184-44348-7-git-send-email-julien.thierry@arm.com>
Message-ID: <20181107215926.GH12248@brain-police>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Sep 26, 2018 at 02:56:23PM +0100, Julien Thierry wrote:
> When an EL2 entry of __kvm_hyp_vector is taken, it means an entry from a
> lower EL was previously taken to exit the guest. Taking that lower EL entry
> already applied vector hardening if needed, so there is no need to do it
> again.
> 
> Only apply vector hardening for exception coming from lower EL.
> 
> Signed-off-by: Julien Thierry <julien.thierry@arm.com>
> Cc: kvmarm at lists.cs.columbia.edu
> ---
>  arch/arm64/kvm/hyp/hyp-entry.S | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
> index 24b4fba..da31386 100644
> --- a/arch/arm64/kvm/hyp/hyp-entry.S
> +++ b/arch/arm64/kvm/hyp/hyp-entry.S
> @@ -257,7 +257,15 @@ ENTRY(__kvm_hyp_vector)
>  ENDPROC(__kvm_hyp_vector)
> 
>  #ifdef CONFIG_KVM_INDIRECT_VECTORS
> -.macro hyp_ventry
> +.macro hyp_el2_ventry
> +	.align 7
> +1:	b	__kvm_hyp_vector + (1b - 0b)
> +	.rept 31
> +	nop
> +	.endr
> +.endm
> +
> +.macro hyp_el1_ventry
>  	.align 7
>  1:	.rept 27
>  	nop
> @@ -290,8 +298,11 @@ alternative_cb_end

I think it would be cleaner to take the EL as a macro parameter, but again,
I defer to Marc and Christoffer.

Will