Hi Stefano, On 11/02/2025 01:56, Stefano Stabellini wrote:
We have received requests to introduce Dom0less vCPU affinity bindings to allow configuring which pCPUs a given vCPU is allowed to run on.After considering different approaches, I am thinking of using the following binding format: vcpu0 { compatible = "xen,vcpu-affinity"; // compatible string id = <0>; // vcpu id hard-affinity = "1,4-7"; // pcpu ranges
This would be CPU logical ID, right? This is a value assigned by Xen based on how pCPU are brought up. So in theory it could change between Xen version as the order is not guaranteed. I know this is what the toolstack is currently using.
However, as we define a new binding, I wonder whether it would be better to instead have a phandle to the CPU device-tree node or just plain MPIDRs? This would guarantee that the vCPU will always land on a given pCPU (this could be important when taking into account the cache topology).
Cheers, -- Julien Grall
