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 ... >> --- a/xen/arch/arm/vpsci.c >> +++ b/xen/arch/arm/vpsci.c >> @@ -78,7 +78,6 @@ static int do_common_cpu_on(register_t t >> ctxt->user_regs.x0 = context_id; >> } >> #endif >> - ctxt->flags = VGCF_online; > >> domain_lock(d); >> rc = arch_set_info_guest(v, ctxt); ... it actually being in context. Thanks for noticing. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
