Gleb Natapov <gleb@xxxxxxxxxx> writes: > On Tue, Jun 18, 2013 at 04:05:08PM +0200, Paolo Bonzini wrote: >> Il 05/06/2013 10:42, Gleb Natapov ha scritto: >> >> > These patches add an emulated MSR_PLATFORM_INFO that kvm guests >> >> > can read as described in section 14.3.2.4 of the Intel SDM. >> >> > The relevant changes and details are in [2/2]; [1/2] makes vendor_intel >> >> > generic. There are atleat two known applications that fail to run because >> >> > of this MSR missing - Sandra and vTune. >> > So I really want Intel opinion on this. Right now it is impossible to >> > implement the MSR correctly in the face of migration (may be with tsc >> > scaling it will be possible) and while it is unimplemented if application >> > tries to use it it fails, but if we will implement it application will >> > just produce incorrect result without any means for user to detect it. >> >> Jun, ping? (Perhaps Gleb you want to ask a more specific question though). >> >> I don't think this is much different from any other RDTSC usage in >> applications (they will typically do their calibration manually, and do >> it just once). I'm applying it to queue. >> > And we do not support application that uses RDTSC directly! If we could > catch those it would be good from support point of view, so the way > MSR_PLATFORM_INFO behaves now it better then proposed alternative. If support is the issue, can't we have a flag that disables this by default and users who want to take the plunge (and be responsible for the consequences) can enable it to read platform_info ? > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
