Hi, Dan
Please ignore previous comments. The above attachment is OK. Sorry for that. :(
> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Zhang, Li
> Sent: Tuesday, July 08, 2008 2:58 PM
> To: dan.magenheimer@xxxxxxxxxx; Xen-Devel (E-mail)
> Cc: Tian, Kevin
> Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and AMD feedback please)
>
> In fact, the issue is from guest. In the guest's terminal, it shows that
> "your
> time source seems to be instable..."
>
> > -----Original Message-----
> > From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> > [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Zhang, Li
> > Sent: Tuesday, July 08, 2008 2:49 PM
> > To: dan.magenheimer@xxxxxxxxxx; Xen-Devel (E-mail)
> > Cc: Tian, Kevin
> > Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and AMD feedback please)
> >
> > Hi, Dan
> >
> > This is the patch which I think it has been completed VT. But there is an
> > instable issue. The reason may be from that this interception is not bound
> > to timer mode yet.
> >
> > Thanks
> > --Li
> >
> > > -----Original Message-----
> > > From: Dan Magenheimer [mailto:dan.magenheimer@xxxxxxxxxx]
> > > Sent: Tuesday, July 08, 2008 11:34 AM
> > > To: Zhang, Li; Xen-Devel (E-mail)
> > > Cc: Tian, Kevin; dan.magenheimer@xxxxxxxxxx
> > > Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and AMD feedback
> please)
> > >
> > > Thanks Kevin and Li --
> > >
> > > A couple of questions:
> > >
> > > 1) If the EXITING flag to be set in vmcs.c is to be controlled by a xen
> > boot
> > > option, would this work:
> > >
> > > static int opt_softtsc = 0;
> > > boolean_param("softtsc", opt_softtsc);
> > > :
> > > min = /* original code */
> > > if (opt_softtsc) min |= CPU_BASED_RDTSC_EXITING;
> > >
> > > 2) In vmx_rdtsc_intercept(/* need regs as param*/) if we change the
> > > rdtscll(tsc) to be tmptsc = hvm_get_guest_tsc() and then set regs->edx
> amd
> > > regs->eax from tmptsc, are we almost done?
> > >
> > > 3) Des Linux or Windows use the CR4.TSD flag and, if so, what code gets
> > called
> > > to force the trap?
> > >
> > > 4) Does Linux or Windows use RDMSR/WRMSR of tsc? Is there already code
> > > somewhere to emulate WRMSR of tsc?
> > >
> > > Sorry I am not very familar with the details of the ia32 instruction
> set.
> > >
> > > Thanks,
> > > Dan
> > >
> > > > -----Original Message-----
> > > > From: Zhang, Li [mailto:li.zhang@xxxxxxxxx]
> > > > Sent: Monday, July 07, 2008 9:00 PM
> > > > To: dan.magenheimer@xxxxxxxxxx; Xen-Devel (E-mail)
> > > > Cc: Tian, Kevin
> > > > Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and AMD
> > > > feedback please)
> > > >
> > > >
> > > > Hi, Dan
> > > > This seems not to be enough. I will cook another patch.
> > > >
> > > > > -----Original Message-----
> > > > > From: Zhang, Li
> > > > > Sent: Tuesday, July 08, 2008 10:28 AM
> > > > > To: Tian, Kevin; 'dan.magenheimer@xxxxxxxxxx'; 'Xen-Devel
> (E-mail)'
> > > > > Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and AMD
> > > > feedback please)
> > > > >
> > > > > Hi, Dan
> > > > >
> > > > > I just add some code to produce vmexit. The function
> > > > vmx_rdtsc_intercept()
> > > > > is not completed. It is needed to add some code to get the
> > > > guest tsc.
> > > > >
> > > > > Thanks
> > > > > --Li
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Tian, Kevin
> > > > > > Sent: Tuesday, July 08, 2008 9:39 AM
> > > > > > To: 'dan.magenheimer@xxxxxxxxxx'; Xen-Devel (E-mail)
> > > > > > Cc: Zhang, Li
> > > > > > Subject: RE: [Xen-devel] Guest TSC and Xen (Intel and
> > > > AMD feedback please)
> > > > > >
> > > > > > >From: Dan Magenheimer [mailto:dan.magenheimer@xxxxxxxxxx]
> > > > > > >Sent: 2008年7月5日 1:32
> > > > > > >
> > > > > > >> >Is this something that you (or Intel in general)
> > > > could look at?
> > > > > > >> >I would be happy to participate but I don't think I
> > > > understand
> > > > > > >> >VT well enough. Once the trap occurs, I suppose
> > > > Xen system time
> > > > > > >> >could be used as the virtual TSC, possibly scaled up.
> > > > > > >> >
> > > > > > >>
> > > > > > >> There should be tiny related to VT, as only turning
> > > > on some bit to
> > > > > > >> allow RDTSC trapping and then the rest stuff should be
> common
> > > > > > >> how to handle it. We'll take a look, but can't
> > > > commit the time due
> > > > > > >> to other scheduled bandwidth. But if you'd like to
> > > > jump in early
> > > > > > >> we definitely can help with VT side.
> > > > > > >
> > > > > > >If you can post a patch with code that:
> > > > > > >
> > > > > > >1) declares a boolean global variable: softtsc = 0
> > > > > > >2) if the variable is set, a rdtsc instruction in any hvm
> > > > > > > domain causes a trap
> > > > > > >3) the trap handler just does a physical rdtsc and returns
> > > > > > >
> > > > > > >then I could probably take it from there.
> > > > > >
> > > > > > OK, and Li in CC will take a look and bake a patch for you.
> > > > > >
> > > > > > Thanks,
> > > > > > Kevin
> > > >
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
tsc.patch
Description: tsc.patch
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
Home