Hi Li,
Shouldn't this
+ regs->eax = tsc & 0xffff;
+ regs->edx = tsc >> 32 & 0xffff;
be
+ regs->eax = tsc & 0xffffffff;
+ regs->edx = tsc >> 32 & 0xffffffff;
Thanks,
Dave
Zhang, Li wrote:
>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
>> > > >
>>
>> _______________________________________________
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>>
>>
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