On Mon, 2025-02-10 at 15:30 +0800, Vern Hao wrote: > I do some test on my Machine with AMD EPYC 7K83, these patches work > on my host, but failed on my guest with qemu. > > in host, use lscpu cmd, you can see invlpgb in flags, but in guest > no. > > So are you plan to support it in guest? How exactly did it fail in the guest? Did the guest simply not use INVLPGB because that CPUID flag was not presented in the CPUID that qemu shows to the guest, or did things crash somehow? My understanding is that while INVLPGB can work in guests, actually implementing that is a whole other can of worms, and definitely not something we should try to tackle at the same time as bare metal support. A TLB flush hypercall, with IRQ-less flushing on the hypervisor side will probably get us 90% of the way there, potentially with less overall complexity than actually supporting INVLPGB in the guest. -- All Rights Reversed.
