On Mon, Jan 14, 2019 at 06:04:27PM +0100, Harald Arnesen wrote: > Qemu with KVM acceleration fails with kernel 5.0-rc1 and 5.0-rc2. > It works fine with 4.20. ... > Bisecting gives: > > c73da3fcab43357feb68cac227194b13e998a8db is the first bad commit > commit c73da3fcab43357feb68cac227194b13e998a8db > Author: Sean Christopherson > Date: Mon Dec 3 13:53:00 2018 -0800 > > KVM: VMX: Properly handle dynamic VM Entry/Exit controls > > EFER and PERF_GLOBAL_CTRL MSRs have dedicated VM Entry/Exit controls > that KVM dynamically toggles based on whether or not the guest's value > for each MSRs differs from the host. Handle the dynamic behavior by > adding a helper that clears the dynamic bits so the bits aren't set > when initializing the VMCS field outside of the dynamic toggling flow. > This makes the handling consistent with similar behavior for other > controls, e.g. pin, exec and sec_exec. More importantly, it eliminates > two global bools that are stealthily modified by setup_vmcs_config. > > Opportunistically clean up a comment and print related to errata for > IA32_PERF_GLOBAL_CTRL. > > Signed-off-by: Sean Christopherson > Signed-off-by: Paolo Bonzini Can you test the attached patch? Found a bug when re-inspecting the guilty commit, the wrong VMCS field is being modifying when applying an errata to disable VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL. Your CPU is listed as one of the models affected by the errata. Compile tested only.