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Date: Wed, 22 Jul 2026 15:07:01 -0700
From: Wei Liu <wei.liu@kernel.org>
To: Yousef Alhouseen <alhouseenyousef@gmail.com>
Cc: "K . Y . Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
	Long Li <longli@microsoft.com>,
	Michael Kelley <mhklinux@outlook.com>, linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mshv_vtl: clear hypercall output before copyout
Message-ID: <20260722220701.GD2020652@liuwe-devbox-debian-v2.local>
References: <20260624172157.2790-1-alhouseenyousef@gmail.com>
 <20260625181314.1399-1-alhouseenyousef@gmail.com>
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In-Reply-To: <20260625181314.1399-1-alhouseenyousef@gmail.com>

On Thu, Jun 25, 2026 at 08:13:14PM +0200, Yousef Alhouseen wrote:
> mshv_vtl_hvcall_call() copies output_size bytes to userspace.
> 
> The output page is freshly allocated. Userspace chooses the copyout length.
> 
> If the hypercall writes less, the tail can contain stale page data.
> 
> Clear the copied range before issuing the hypercall.
> 
> Also check both bounce page allocations before either page is used.
> 
> Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>

Applied. Thanks.