On Wed, 28 Nov 2018 17:50:21 +0100 Cédric Le Goater <c...@kaod.org> wrote:
> On 11/28/18 10:35 AM, Greg Kurz wrote: > > On Wed, 28 Nov 2018 13:57:14 +1100 > > David Gibson <da...@gibson.dropbear.id.au> wrote: > > > >> On Fri, Nov 16, 2018 at 11:57:05AM +0100, Cédric Le Goater wrote: > >>> We will need to use xics_max_server_number() to create the sPAPRXive > >>> object modeling the interrupt controller of the machine which is > >>> created before the CPUs. > >>> > >>> Signed-off-by: Cédric Le Goater <c...@kaod.org> > >> > >> My only concern here is that this moves the spapr_set_vsmt_mode() > >> before some of the sanity checks in spapr_init_cpus(). Are we certain > >> there are no edge cases that could cause badness? > >> > > > > The early checks in spapr_init_cpus() filter out topologies that would > > result in partially filled cores. They're only related to the rest of > > the code that creates the boot CPUs. Before commit 1a5008fc17, > > spapr_set_vsmt_mode() was even being called before spapr_init_cpus(). > > The rationale to move it there was to ensure it is called before the > > first user of spapr->vsmt, which happens to be a call to > > xics_max_server_number(). > > > > Now that xics_max_server_number() needs to be called even earlier, I think a > > better change is to have xics_max_server_number() to call > > spapr_set_vsmt_mode() > > if spapr->vsmt isn't set. > > That 'smt' routine is black magic to me and I would not dare touching it. > I don't suggest to change it, just to ensure it gets called before spapr->vsmt gets used. But don't worry, I'll have a deeper look and send a patch :) > C. > > > > >>> --- > >>> hw/ppc/spapr.c | 10 +++++----- > >>> 1 file changed, 5 insertions(+), 5 deletions(-) > >>> > >>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > >>> index 7afd1a175bf2..50cb9f9f4a02 100644 > >>> --- a/hw/ppc/spapr.c > >>> +++ b/hw/ppc/spapr.c > >>> @@ -2466,11 +2466,6 @@ static void spapr_init_cpus(sPAPRMachineState > >>> *spapr) > >>> boot_cores_nr = possible_cpus->len; > >>> } > >>> > >>> - /* VSMT must be set in order to be able to compute VCPU ids, ie to > >>> - * call xics_max_server_number() or spapr_vcpu_id(). > >>> - */ > >>> - spapr_set_vsmt_mode(spapr, &error_fatal); > >>> - > >>> if (smc->pre_2_10_has_unused_icps) { > >>> int i; > >>> > >>> @@ -2593,6 +2588,11 @@ static void spapr_machine_init(MachineState > >>> *machine) > >>> /* Setup a load limit for the ramdisk leaving room for SLOF and FDT > >>> */ > >>> load_limit = MIN(spapr->rma_size, RTAS_MAX_ADDR) - FW_OVERHEAD; > >>> > >>> + /* VSMT must be set in order to be able to compute VCPU ids, ie to > >>> + * call xics_max_server_number() or spapr_vcpu_id(). > >>> + */ > >>> + spapr_set_vsmt_mode(spapr, &error_fatal); > >>> + > >>> /* Set up Interrupt Controller before we create the VCPUs */ > >>> smc->irq->init(spapr, &error_fatal); > >>> > >> > > >