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. Cheers, -- Julien Grall
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