Wanpeng Li <kernellwp@xxxxxxxxx> writes: > 2018-01-16 1:30 GMT+08:00 Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>: >> Early RFC. I'll refer to this patchset in my DevConf/FOSDEM >> presentations. >> >> When running nested KVM on Hyper-V it's possible to use so called >> 'Enlightened VMCS' and do normal memory reads/writes instead of >> doing VMWRITE/VMREAD instructions. Tests show that this speeds up >> tight CPUID loop almost 3 times: >> >> Before: >> ./cpuid_tight >> 20459 >> >> After: >> ./cpuid_tight >> 7698 > > Maybe you can apply a similar idea to kvm nested on kvm. > Yes we can. Basically, that would mean directly accessing 'struct vmcs12' from L1 hypervisor. -- Vitaly
