lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 09 Nov 2009 18:28:34 -0700
From:	Alex Williamson <alex.williamson@...com>
To:	David Woodhouse <dwmw2@...radead.org>
Cc:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH] intel-iommu: Obey coherent_dma_mask for alloc_coherent
 on passthrough

On Tue, 2009-11-10 at 01:01 +0000, David Woodhouse wrote:
> On Tue, 2009-11-10 at 00:46 +0000, David Woodhouse wrote:
> > 
> >         if (iommu_no_mapping(hwdev))
> > -               return paddr;
> > +               return paddr > dma_mask - size ? 0 : paddr; 
> 
> Hm, that's still wrong. If your mask is 0xffffffff and you map
> 0xfffff000 + 0x1000, that should be allowed, right? How about:
> 
> 	return paddr <= dma_mask - size + 1 ? paddr : 0;

Ok, I was going to suggest that there was probably a -1 missing from my
patch.  I'd also be surprised if you could actually get a paddr + size -
1 from a single allocation that would wrap.  Would a device even be able
to handle that for DMA?

> And is this strictly necessary as part of the patch we're discussing?

Yeah, we could probably do without it.  As for the commit comment, it's
rather scathing, but I can live with it.  Thanks,

Alex

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists