On 08/02/16 16:31, Boris Ostrovsky wrote: > > > On 02/08/2016 11:26 AM, Andrew Cooper wrote: >> On 08/02/16 16:12, Boris Ostrovsky wrote: >>> >>> On 02/08/2016 11:05 AM, Andrew Cooper wrote: >>>> For compatibility with other virtualisation specs, Xen's cpuid leaves >>>> shift depending on configuration. >>>> >>>> Spec at >>>> http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/include/public/arch-x86/cpuid.h;h=d709340f18d089560b959835eabb7b6609542c7e;hb=HEAD#l33 >>>> >>>> >>>> >>>> Basically, they are either at 0x40000000, or 0x40000100 if viridian or >>>> vmware compatibility has been enabled. >>> (Also in arch/x86/include/asm/xen/cpuid.h in Linux tree). >> The other complication is that, for a PV guest, you must use the forced >> emulation prefix for the cpuid instruction to trap into the hypervisor. >> >> This either means you must be sure you are under Xen to start with, or >> use an extable entry to catch the #UD fault if you are not under Xen. > > I think we are OK for PV because this code will be executed after > pvops are set and so we will be calling xen_cpuid().
Great. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
