On 27.12.2019 12:27, Julien Grall wrote: > Hi Jan, > > On Fri, 27 Dec 2019, 09:22 Jan Beulich, <[email protected]> wrote: > >> On 23.12.2019 18:33, Julien Grall wrote: >>> Hi Jan, >>> >>> On 20/12/2019 14:55, Jan Beulich wrote: >>>> There's been effectively no use of the field for HVM. >>>> >>>> Also shrink the field to unsigned int, even if this doesn't immediately >>>> yield any space benefit for the structure itself. The resulting 32-bit >>>> padding slot can eventually be used for some other field. The change in >>>> size makes accesses slightly more efficient though, as no REX.W prefix >>>> is going to be needed anymore on the respective insns. >>>> >>>> Mirror the HVM side change here (dropping of setting the field to >>>> VGCF_online) also to Arm, on the assumption that it was cloned like >>>> this originally. VGCF_online really should simply and consistently be >>>> the guest view of the inverse of VPF_down, and hence needs representing >>>> only in the get/set vCPU context interfaces. >>> >>> But vPSCI is just a wrapper to get/set vCPU context interfaces. Your >>> changes below will clearly break bring-up of secondary vCPUs on Arm. >>> >>> This is because arch_set_guest_info() will rely on this flag to >>> clear/set VPF_down in the pause flags. >>> >>> So I think the line in arm/vpsci.c should be left alone. >> >> Oh, I see - I didn't notice this (ab)use despite ... >> > > Out of Interest, why do you think it is an abuse here and not in the > toolstack? > > How do you suggest to improve it? I can add it in my improvement list for > Arm.
Oh, "abuse" was about the arch_set_guest_info() use, not the use of the flag by the tool stack. Jan _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
