On 25/09/20 22:29, Eduardo Habkost wrote: >> No, it's not possible. KVM doesn't have a say on what the processor >> writes in the tracing packets. > Can KVM refuse to enable packet generation if CSbase is not zero > and CPUID.(EAX=14H,ECX=0)[bit 31] seen by guest is different from > host?
Yes, but the processor could change operating mode (and hence CSbase) while tracing is active. This is very unlikely, since it would require nonzero CS-base and a 32-bit host, but in principle not impossible (could be a firmware call, for example). The only solution is for KVM to accept both, and for QEMU to refuse a setting that does not match the host. Paolo
