On 27/06/2018 14:05, Alexandro Sanchez Bach wrote: > Some drivers in my FreeBSD-based guest kernel are reading > MSR_K8_TOP_MEM1 and MSR_K8_TOP_MEM2, which are not implemented in KVM, > and do not exist in my host system (these are AMD MSRs, while host is > Intel). The reason is that this kernel expects to run on an AMD Jaguar > Family CPU. I need fix this problem, so I had few questions: Do you mean that the kernel was compiled to not look at CPUID? That is a bit weird. > 1. Is it possible to make unimplemented MSR accesses fall back to QEMU? > > 2. If not, is it possible to make QEMU explicitly tell KVM what the > value of those MSRs should be? > > 3. If not, should those MSRs be implemented and upstreamed to KVM? I.e. > would such a patch be accepted, despite these being AMD-specific registers? > > After reading the API, it seems to me the answer for (1) and (2) is ‘no’ > , but I wanted to ask just in case. Correct. As for (3), it depends on why you need that. Paolo
