On 26/02/18 10:44, Jan Beulich wrote: > All, > > if running PV Linux on older Xen (4.5 and earlier) is relevant, it may be > necessary to use a mechanism other than IBRS to mitigate Spectre v2 > on Skylake. That is because the new MSR value can't be migrated > prior to migration v2. Of course one option would be to retrofit some > mechanism into newer Xen versions that makes them accept whatever > extension to e.g. struct hvm_hw_cpu one might want to invent for > the older Xen versions. But that doesn't seem very desirable.
Can you please elaborate a little bit more what the real problem is? I _think_ you are referring to the problem that a pv kernel would want to use IBRS for mitigation of Spectre V2 and after a migration that setting would be lost. If this is the case I believe the easiest solution would be to let the kernel set the MSR again after leaving suspended state. suspend/resume require hooks in pv kernels after all. Juergen _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
