On Fri, Mar 13, 2020 at 09:45:15 +0100, Christian Ehrhardt wrote:
On Tue, Mar 10, 2020 at 11:48 AM Christian Ehrhardt < christian.ehrhardt@canonical.com> wrote:
One of the mitigation methods for TAA[1] is to disable TSX support on the host system. Linux added a mechanism to disable TSX globally through the kernel command line, and many Linux distributions now default to tsx=off. This makes existing CPU models that have HLE and RTM enabled not usable anymore.
Add new versions of all CPU models that have the HLE and RTM features enabled, that can be used when TSX is disabled in the host system.
On systems disabling the features without those types defined in cpu-maps users end up without modern CPU types in the list of usable CPUs to use in the likes of virsh domcapabilities or tools higher in the stack like virt-manager.
This adds: -Cascadelake-Server-noTSX -Icelake-Client-noTSX -Icelake-Server-noTSX -Skylake-Server-noTSX-IBRS -Skylake-Client-noTSX-IBRS
Introduced in QEMU by commit v4.2.0-rc2-3-g9ab2237f19 (function) and commit v4.2.0-rc2-4-g02fa60d101 (names)
Ping - anything else that we need for this v2 right now to accept it?
I know in the long run Jiri would want to auto-select the non noTSX types. But as I outlined before I'd consider this a later change or would need some guidance where/how it is envisioned to do tat preference.
Sorry, I already started working on this additional patch as I'd like it to be pushed right after yours. But I got distracted by other higher priority things. I hope to finish it and send for a review soon. Jirka