Amit Shah wrote: > On Tuesday 20 November 2007 15:17:54 Avi Kivity wrote: > >> Amit Shah wrote: >> >>> On Tuesday 20 November 2007 00:38:05 Markus Rechberger wrote: >>> >>>> this patch discards MSR writes to the Performance Event-Select >>>> Registers, this is the first issue why vista seems to fail although now >>>> vista ends up in an endless loop a bit later. >>>> Qemu currently also discards those writes. >>>> >>> Won't this make the corresponding rdmsrs fail? What happens when the >>> rdmsr returns an error, but windows then uses some garbage value (as it >>> thinks the wrmsr succeeded, so the rdmsr also should)? >>> >> rdmsr will inject #GP for these msrs. Implementing set_msr() doesn't >> affect rdmsr. >> > > >From the AMD programming manual, vol 2: > > The performance event-select registers can be read and written only by system > software running at CPL = 0 using the RDMSR and WRMSR instructions, > respectively. Any attempt to read or write these registers at CPL > 0 causes > a general-protection exception to occur. >
Look through the code that implements rdmsr, it doesn't care about the manuals and will happily inject a #GP for rdmsr of any unimplemented msr (like PerfEvtSel) wrmsr and rdmsr implementations are not linked. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
