Hi there,
I am using Xen-3.2 on Intel-VT hardware. My guest VM is running Linux kernel
2.6.21 in HVM mode.
I was trying to do some emulation from the hypervisor and my code was failing to
emulate FXSAVE instructions. I looked on the mailing list and found the
following patch that does that:
"[Xen-devel] [PATCH 2/4] Enable VirtualPC 2007 run on top of XEN:
fxsave" from [Su, Disheng]
However, when I applied this patch it is still not working. I am going to the
default case of this patch that directly calls "goto cannot_emulate".
When I printed the instruction it is like this: 0f ae e8. The value of modrm_reg
that patch uses to check which case statement to execute is 05.
The patch only handles the value 0.
Could some explain what does this mean? And, how to solve this problem?
Any help would be appreciated.
Thanks,
Abhinav
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Abhinav Srivastava wrote:> Hi there, > > I am using Xen-3.2 on Intel-VT hardware. My guest VM is running Linux > kernel 2.6.21 in HVM mode. > > I was trying to do some emulation from the hypervisor and my code was > failing to emulate FXSAVE instructions. I looked on the mailing list > and found the following patch that does that: > > "[Xen-devel] [PATCH 2/4] Enable VirtualPC 2007 run on top of XEN: > fxsave" from [Su, Disheng] > > However, when I applied this patch it is still not working. I am > going to the default case of this patch that directly calls "goto > cannot_emulate". When I printed the instruction it is like this: 0f > ae e8. The value of modrm_reg that patch uses to check which case > statement to execute is 05. The patch only handles the value 0. >"0f ae e8" is the lfence instruction. It isn''t handled in this patch... You can refer to Intel Software Developer Manual Vol.2B A.4.2 for detail information.> Could some explain what does this mean? And, how to solve this > problem? >Don''t why you need to emulate this instruction... Do you want to emulate instructions step by step? How about bypass this "lfence"?> Any help would be appreciated. > > Thanks, > Abhinav > > > > Explore your hobbies and interests. Go to > http://in.promos.yahoo.com/groups/ > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-develBest Regards, Disheng, Su _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Yes, I am trying to emulate instructions step by step in some scenarios and I am getting this instruction. I tried skipping this instruction but it did not work. Do you know any patch or workaround for that? Thanks, Abhinav --- On Fri, 18/7/08, Su, Disheng <disheng.su@intel.com> wrote:> From: Su, Disheng <disheng.su@intel.com> > Subject: RE: [Xen-devel] FXSAVE instruction emulation > To: abhinavs_iitkgp@yahoo.co.in, xen-devel@lists.xensource.com > Cc: "Su, Disheng" <disheng.su@intel.com> > Date: Friday, 18 July, 2008, 8:51 AM > Abhinav Srivastava wrote: > > Hi there, > > > > I am using Xen-3.2 on Intel-VT hardware. My guest VM > is running Linux > > kernel 2.6.21 in HVM mode. > > > > I was trying to do some emulation from the hypervisor > and my code was > > failing to emulate FXSAVE instructions. I looked on > the mailing list > > and found the following patch that does that: > > > > "[Xen-devel] [PATCH 2/4] Enable VirtualPC 2007 > run on top of XEN: > > fxsave" from [Su, Disheng] > > > > However, when I applied this patch it is still not > working. I am > > going to the default case of this patch that directly > calls "goto > > cannot_emulate". When I printed the instruction > it is like this: 0f > > ae e8. The value of modrm_reg that patch uses to check > which case > > statement to execute is 05. The patch only handles the > value 0. > > > "0f ae e8" is the lfence instruction. It > isn''t handled in this patch... > You can refer to Intel Software Developer Manual Vol.2B > A.4.2 for detail > information. > > Could some explain what does this mean? And, how to > solve this > > problem? > > > Don''t why you need to emulate this instruction... > Do you want to emulate instructions step by step? > How about bypass this "lfence"? > > Any help would be appreciated. > > > > Thanks, > > Abhinav > > > > > > > > Explore your hobbies and interests. Go to > > http://in.promos.yahoo.com/groups/ > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xensource.com > > http://lists.xensource.com/xen-devel > > > > Best Regards, > Disheng, Su > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-develBring your gang together. Do your thing. Find your favourite Yahoo! group at http://in.promos.yahoo.com/groups/ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel