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From: Stefano Stabellini <sstabellini@kernel.org>
To: Jan Beulich <jbeulich@suse.com>
Cc: Simon Leiner <simon@leiner.me>,
	xen-devel@lists.xenproject.org,  sstabellini@kernel.org,
	jgross@suse.com, julien@xen.org
Subject: Re: [PATCH 2/2] arm/xen: Add misuse warning to virt_to_gfn
Date: Tue, 25 Aug 2020 16:48:48 -0700 (PDT)
Message-ID: <alpine.DEB.2.21.2008251647100.24407@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <374f42a0-b618-8b90-71b5-0a865ea1ddbb@suse.com>

On Tue, 25 Aug 2020, Jan Beulich wrote:
> On 25.08.2020 11:31, Simon Leiner wrote:
> > --- a/include/xen/arm/page.h
> > +++ b/include/xen/arm/page.h
> > @@ -76,7 +76,11 @@ static inline unsigned long bfn_to_pfn(unsigned long bfn)
> >  #define bfn_to_local_pfn(bfn)	bfn_to_pfn(bfn)
> >  
> >  /* VIRT <-> GUEST conversion */
> > -#define virt_to_gfn(v)		(pfn_to_gfn(virt_to_phys(v) >> XEN_PAGE_SHIFT))
> > +#define virt_to_gfn(v)                                                         \
> > +	({                                                                     \
> > +		WARN_ON_ONCE(is_vmalloc_addr(v));                              \
> > +		pfn_to_gfn(virt_to_phys(v) >> XEN_PAGE_SHIFT);                 \
> > +	})
> 
> Shouldn't such a check cover more than just the vmalloc range,
> i.e. everything outside of what __va() can validly return?

Keep in mind that this patch is meant as sister patch to
https://marc.info/?l=xen-devel&m=159834800203817
so it makes sense to check for vmalloc addresses specifically.

That said, I am not aware of a good way to implement the __va test you
are suggesting.


  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Aw: [Linux] [ARM] Granting memory obtained from the DMA API>
2020-08-25  9:31 ` [PATCH 1/2] xen/xenbus: Fix granting of vmalloc'd memory Simon Leiner
2020-08-25  9:31   ` [PATCH 2/2] arm/xen: Add misuse warning to virt_to_gfn Simon Leiner
2020-08-25 12:16     ` Jan Beulich
2020-08-25 23:48       ` Stefano Stabellini [this message]
2020-08-26  6:20         ` Jan Beulich
2020-08-26  7:50           ` Simon Leiner
2020-08-26  7:59             ` Jürgen Groß
2020-08-26  8:14               ` Simon Leiner
2020-08-26  8:27                 ` Jürgen Groß
2020-08-26  8:30                   ` Simon Leiner
2020-08-25 23:58     ` Stefano Stabellini
2020-08-26 18:37     ` Julien Grall
2020-08-27  5:21       ` Jürgen Groß
2020-08-27  8:24         ` Julien Grall
2020-08-27  8:35           ` Jürgen Groß
2020-08-27 16:04             ` Stefano Stabellini
2020-08-25 23:55   ` [PATCH 1/2] xen/xenbus: Fix granting of vmalloc'd memory Stefano Stabellini

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