He, Qing
2006-Dec-01 07:33 UTC
[Xen-devel] [PATCH] make shared_info architecture independent
This patch changes the structure of shared_info and vcpu_info, so that its members (event channel related flags) have the same offset in x86_32/x86_64 environment. This modification enables 32bit PV-on-HVM driver to run transparently on both 32bit and 64bit hypervisor. Signed-off-by: Xiaowei Yang <xiaowei.yang@intel.com> Signed-off-by: Qing He <qing.he@intel.com> Thanks, Qing He/Xiaowei Yang _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2006-Dec-01 08:04 UTC
Re: [Xen-devel] [PATCH] make shared_info architecture independent
On 1/12/06 7:33 am, "He, Qing" <qing.he@intel.com> wrote:> This patch changes the structure of shared_info and vcpu_info, so that > its members (event channel related flags) have the same offset in > x86_32/x86_64 environment. This modification enables 32bit PV-on-HVM > driver to run transparently on both 32bit and 64bit hypervisor.Breaks ABI compatibility, and Jan Beulich''s PV-PAE-on-64 patches can be extended for the HVM case. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Yang, Xiaowei
2006-Dec-01 08:17 UTC
RE: [Xen-devel] [PATCH] make shared_info architecture independent
>Breaks ABI compatibility, and Jan Beulich''s PV-PAE-on-64 patches can be >extended for the HVM case. >Keir, I don''t quite understand what "break ABI compatibility" mean? Doesn''t it mean old domX kernel can''t run with new HV or vice versa? Since we only made a small change to evtchn structure inside and exported APIs is untouched, we think it won''t affect others. Thanks, Xiaowei _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2006-Dec-01 09:14 UTC
Re: [Xen-devel] [PATCH] make shared_info architecture independent
On 1/12/06 08:17, "Yang, Xiaowei" <xiaowei.yang@intel.com> wrote:> I don''t quite understand what "break ABI compatibility" mean? Doesn''t it > mean old domX kernel can''t run with new HV or vice versa? Since we only > made a small change to evtchn structure inside and exported APIs is > untouched, we think it won''t affect others.Yes, that''s precisely what ABI compatibility means. Your patch breaks it and so is unacceptable. Luckily Jan Beulich has done the hard work of supporting the current 32-bit ABI on a 64-bit hypervisor. He did this primarily to support paravirtual PAE guests on 64-bit hypervisor, but I''m sure the work can be (fairly) easily extended to support 32-bit PV-on-HVM drivers on 64-bit hypervisor. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel