On Thu, Jun 28, 2018 at 12:15:14PM +0200, Greg Kurz wrote: > It is currently not possible to run a pseries-2.12 or older machine > with HV KVM. QEMU prints the following and exits right away. > > qemu-system-ppc64: KVM doesn't support for base page shift 34 > > The "hpt-max-page-size" capability was recently added to spapr to hide > host configuration details from HPT mode guests. Its default value for > newer machine types is 64k. > > For backwards compatibility, pseries-2.12 and older machine types need > a different value. This is handled as usual in a class init function. > The default value is 16G, ie, all page sizes supported by POWER7 and > newer CPUs, but HV KVM requires guest pages to be hpa contiguous as > well as gpa contiguous. The default value is the page size used to > back the guest RAM in this case. > > Unfortunately kvmppc_hpt_needs_host_contiguous_pages()->kvm_enabled() is > called way before KVM init and returns false, even if the user requested > KVM. We thus end up selecting 16G, which isn't supported by HV KVM. > > We fix this by moving the logic to spapr_machine_init() because this > is the earliest call where we're sure kvm_enabled() can be trusted. > Since the user cannot pass cap-hpt-max-page-size=0, we set the default > to 0 in the pseries-2.12 class init function and use that as a flag > in spapr_machine_init() to do the real work. > > Signed-off-by: Greg Kurz <gr...@kaod.org> > --- > hw/ppc/spapr.c | 25 ++++++++++++++++++------- > 1 file changed, 18 insertions(+), 7 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 8cc996d0b822..1eb45cd8c424 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -2527,6 +2527,18 @@ static void spapr_machine_init(MachineState *machine) > QLIST_INIT(&spapr->phbs); > QTAILQ_INIT(&spapr->pending_dimm_unplugs); > > + /* This is for pseries-2.12 and older machine types */ > + if (!smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE]) { > + uint8_t mps; > + > + if (kvmppc_hpt_needs_host_contiguous_pages()) { > + mps = ctz64(qemu_getrampagesize()); > + } else { > + mps = 34; /* allow everything up to 16GiB, i.e. everything */ > + } > + smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = mps; > + } > +
The logic above should be folded into spapr_caps_init(). > /* Determine capabilities to run with */ > spapr_caps_init(spapr); > > @@ -4103,17 +4115,16 @@ static void > spapr_machine_2_12_instance_options(MachineState *machine) > static void spapr_machine_2_12_class_options(MachineClass *mc) > { > sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc); > - uint8_t mps; > > spapr_machine_3_0_class_options(mc); > SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_12); > > - if (kvmppc_hpt_needs_host_contiguous_pages()) { > - mps = ctz64(qemu_getrampagesize()); > - } else { > - mps = 34; /* allow everything up to 16GiB, i.e. everything */ > - } > - smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = mps; > + /* We depend on kvm_enabled() to choose a default value for the > + * hpt-max-page-size capability. Of course we can't do it here > + * because this is too early and the HW accelerator isn't initialzed > + * yet. Postpone this to spapr_machine_init(). > + */ > + smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 0; > } > > DEFINE_SPAPR_MACHINE(2_12, "2.12", false); > -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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