From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: [PATCH] libxc: remove most of tools/libxc/xc_dom_compat_linux.c Date: Mon, 19 Oct 2015 12:36:51 +0200 Message-ID: <5624C7C3.2030007@suse.com> References: <1444131327-22000-1-git-send-email-jgross@suse.com> <5613C400.4040209@citrix.com> <20151006125858.GB29124@zion.uk.xensource.com> <5613C773.5030901@citrix.com> <1444137461.5302.167.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1444137461.5302.167.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , Andrew Cooper , Wei Liu Cc: xen-devel@lists.xen.org, ian.jackson@eu.citrix.com, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On 10/06/2015 03:17 PM, Ian Campbell wrote: > On Tue, 2015-10-06 at 14:06 +0100, Andrew Cooper wrote: >> On 06/10/15 13:58, Wei Liu wrote: >>> On Tue, Oct 06, 2015 at 01:52:16PM +0100, Andrew Cooper wrote: >>>> On 06/10/15 12:35, Juergen Gross wrote: >>>>> In tools/libxc/xc_dom_compat_linux.c only xc_linux_build() is >>>>> currently >>>>> being used by an in-tree component (qemu-xen). All other functions >>>>> are >>>>> superfluous wrappers of the domain builder which can be removed. >>>>> >>>>> Suggested-by: Ian Campbell >>>>> Signed-off-by: Juergen Gross >>>> Sorry, but NACK. They are *not* superfluous. >>>> >>>> XenServer uses them; xc_dom_linux_build() is the only way to apply >>>> XSA-25 size restrictions to PV kernels and initrds. >>>> >>> Could you explain a bit more about this? How could this particular >>> function apply restrictions? >>> >>> Unfortunately XSA-25 is not on XSA page so I have no idea what that is. >>> >>> Wei. >> >> Older XSAs are listed on the wiki >> http://wiki.xen.org/wiki/Security_Announcements >> >> XSA-25 introduced xc_dom_{kernel,ramdisk}_max_size() to set upper >> decompression limits on the kernel and initrd. >> >> To use them, a struct xc_dom_image *dom is needed, which means the only >> safe way of constructing PV domains is >> >> xc_dom_allocate() >> xc_dom_kernel_max_size() >> xc_dom_ramdisk_max_size() >> xc_dom_linux_build() >> >> To have the decompression limits in place before decompression starts. > > No it isn't. > > xc_dom_linux_build is implemented in terms of the non-compat xc_dom_* > functions, so it should be possible to do what you want with out using the > compat wrapper. > > If there is some obscure reason this isn't the case then we should fix > that, not carry around the compat options for ever as a workaround (fixes > include but are not limited to promoting xc_dom_linux_build into a non > -compat helper). Any further comments? Andrew, are you okay with Ian's statement? Ian, does this mean you are Ack-ing the patch? Juergen