On Thu, Sep 12, 2024 at 03:44:38PM +0000, Jon Kohler wrote: > > It is only worth implementing the long sequence in VMEXIT_ONLY mode if it is > > significantly better than toggling the MSR. > > Thanks for the pointer! I hadn’t seen that second sequence. I’ll do measurements on > three cases and come back with data from an SPR system. > 1. as-is (wrmsr on entry and exit) > 2. Short sequence (as a baseline) > 3. Long sequence I wonder if virtual SPEC_CTRL feature introduced in below series can provide speedup, as it can replace the MSR toggling with faster VMCS operations: https://lore.kernel.org/kvm/20240410143446.797262-1-chao.gao@xxxxxxxxx/ Adding Chao for their opinion.
