From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH 1/1] x86/hvm: prevent hvm_free_ioreq_gmfn()
 clobber of arbitrary memory
Date: Tue, 14 Apr 2015 12:47:46 +0100
Message-ID: <552D1A820200007800071DF7@mail.emea.novell.com>
References: <1428940903-18302-1-git-send-email-dslutz@verizon.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>, Don Slutz <dslutz@verizon.com>
Cc: Keir Fraser <keir@xen.org>, xen-devel@lists.xen.org
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>>> On 13.04.15 at 18:01, <dslutz@verizon.com> wrote:
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -536,8 +536,9 @@ static int hvm_alloc_ioreq_gmfn(struct domain *d, 
> unsigned long *gmfn)
>  
>  static void hvm_free_ioreq_gmfn(struct domain *d, unsigned long gmfn)
>  {
> -    unsigned int i = gmfn - d->arch.hvm_domain.ioreq_gmfn.base;
> +    unsigned long i = gmfn - d->arch.hvm_domain.ioreq_gmfn.base;
>  
> +    BUG_ON(i >= sizeof(d->arch.hvm_domain.ioreq_gmfn.mask) * 8);
>      clear_bit(i, &d->arch.hvm_domain.ioreq_gmfn.mask);
>  }

I'd be happier with an ASSERT() - Andrew?

Jan