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] [day] [month] [year] [list]
Date:	Mon, 7 Apr 2014 18:11:48 +0100
From:	David Vrabel <>
To:	Roger Pau Monné <>
CC:	<>, <>,
	Konrad Rzeszutek Wilk <>,
	Boris Ostrovsky <>
Subject: Re: [PATCH] xen-blkback: only attach blkback if the required features
 are met

On 04/04/14 16:13, Roger Pau Monné wrote:
> On 04/04/14 17:01, David Vrabel wrote:
>> On 04/04/14 15:41, Roger Pau Monne wrote:
>>> Blkback cannot work properly on auto-translated guests if Xen doesn't
>>> update the IOMMU when performing grant maps/unmaps, so only attach if
>>> the newly introduced XENFEAT_hvm_gntmap_supports_iommu is found.
>> Can you explain the problem in more detail and which guest
>> configurations are affected?
>> This isn't a problem that is specific to blkback, but any backend that
>> grant maps and passes the foreign pages to a device so there needs to be
>> a generic solution.
>> Why can't this be fixed by having the swiotlb bounce foreign pages?
> Yes, it could be fixed with that, FreeBSD has been doing it for a long time.
> But since nobody has complained about this, and the issue has been there
> for a long time, I'm not sure it's worth adding all the bounce buffer
> code for what seems to be an unused configuration.

Ok.  Now that netback also grant maps.  Can you make this a generic
function and call from netback and blkback?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists