Hi, I have few queries regarding qemu-kvm support of Spectre related fixes at 4.4.* LTS Kernel.
I see that in upstream kernels, svm_vcpu_run() calls x86_spec_ctrl_set_guest() and x86_spec_ctrl_restore_host(). And calling into x86_virt_spec_ctrl(), that sets IBRS/IBPB/SSBD bits accordingly for guest context. Related commit IDs below: commit 5cf687548705412da47c9cec342fd952d71ed3d5 commit ccbcd2674472a978b48c91c1fbfb66c0ff959f24 Looks like this change is not fully ported to 4.4 LTS yet. x86_spec_ctrl_set_guest() and x86_spec_ctrl_restore_host() interfaces are available, however looks like svm_vcpu_run() is not calling them. So qemu-kvm running on 4.4 kernels may not have SPEC_CTRL set properly in guest context. Is there a plan to backport above changes fully into 4.4 LTS kernel?. Thanks, Paulose.
