On 13/03/2017 19:27, Jim Mattson wrote: > I would expect that any reasonable CPU will support "RDRAND exiting" > iff it supports RDRAND (i.e. CPUID.01H:ECX.RDRAND[bit 30]). > Similarly, any reasonable CPU will support "RDSEED exiting" iff it > supports RDSEED (i.e. CPUID.(EAX=07H, ECX=0H):EBX.RDSEED[bit 18]). > > Shouldn't there be some code in vmx_cpuid_update to adjust the > vmx->nested.nested_vmx_secondary_ctls_high bits for "RDRAND exiting" > and "RDSEED exiting," as there already is for "enable RDTSCP"? Enable RDTSCP is a bit different in that the instruction itself is disabled rather than the VMEXIT, still it would probably be a good idea. One thing to be careful about is any conflicts with David Matlack's work to customize the MSRs for processor models, since there's no prescribed ordering of KVM_SET_CPUID2 and KVM_SET_MSR. Maybe nested_vmx_setup_ctls_msrs can save the "default" nested_*_ctls_*; then vmx_restore_control_msr can refer to those in order to check the written value against the supported bits. Paolo
