On 03/01/2025 2:25 pm, Fonyuy-Asheri Caleb wrote: > Hello, > > I am interested in finding understanding how xen handles CPUID > faulting and > VM exits in general. Please can someone indicate to me the concerned > files? > > I want to know how xen detects the execution of the CPUID instruction and > ensures a guest only gets the features defined in cpuid-autogen.h file > depending on the guest type. > > I started looking at the file xen/arch/x86/cpuid.c but don't really > know which other > files to check next.
https://xenbits.xen.org/docs/unstable/features/feature-levelling.html has a reasonable introduction. Being nearly a decade old, it's slightly stale. AMD now have CPUID Faulting capability too, new in Zen4 CPUs IIRC. LCAP_faulting specifically is the constant you're looking for, in the Xen code. ~Andrew
