Received-SPF: pass (google.com: domain of linux-kernel+bounces-133880-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Sat, 06 Apr 2024 10:58:10 +0100
Message-ID: <87edbisthp.wl-maz@kernel.org>
From: Marc Zyngier <maz@kernel.org>
To: Nianyao Tang <tangnianyao@huawei.com>,
    Thomas Gleixner <tglx@linutronix.de>
Cc: 	<yuzenghui@huawei.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<guoyang2@huawei.com>,
	<wangwudi@hisilicon.com>
Subject: Re: [RESPIN PATCH] irqchip/gic-v4.1:Fix VSYNC referencing an unmapped VPE
In-Reply-To: <20240406022737.3898763-1-tangnianyao@huawei.com>
References: <20240406022737.3898763-1-tangnianyao@huawei.com>
User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue)
 FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/28.2
 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO)
Precedence: bulk
MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue")
Content-Type: text/plain; charset=US-ASCII

On Sat, 06 Apr 2024 03:27:37 +0100,
Nianyao Tang <tangnianyao@huawei.com> wrote:
> 
> As per the GICv4.1 spec (Arm IHI 0069H, 5.3.19):
> 
> "A VMAPP with {V, Alloc}=={0, x} is self-synchronizing, This means the
> ITS command queue does not show the command as consumed until all of
> its effects are completed."
> 
> Furthermore, VSYNC is allowed to deliver an SError when referencing a
> non existent VPE.
> 
> By these definitions, a VMAPP followed by a VSYNC is a bug, as the
> later references a VPE that has been unmapped by the former.
> 
> Fix it by eliding the VSYNC in this scenario.
> 
> Fixes: 64edfaa9a234 ("irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP")
> 
> Signed-off-by: Nianyao Tang <tangnianyao@huawei.com>
> Reviewed-by: Marc Zyngier <maz@kernel.org>

Thanks for having taken my remarks into account, it looks good now.

Thomas, can you please take this as a fix for 6.9?

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.