On Mon, Jul 02, 2018 at 10:54:56AM +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. The > default value must be set during machine init, because we can safely > assume that KVM is initialized at this point. > > We fix this by moving the logic to default_caps_with_cpu(). 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 to do the > real work. > > Signed-off-by: Greg Kurz <gr...@kaod.org>
Applied to ppc-for-3.0, thanks.
> ---
> v3: - moved logic to default_caps_with_cpu()
>
> v2: - moved logic under spapr_caps_init()
> ---
> hw/ppc/spapr.c | 13 ++++++-------
> hw/ppc/spapr_caps.c | 13 +++++++++++++
> 2 files changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index b2baec026ff4..062d9dc346d4 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -4095,17 +4095,16 @@ 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 machine init (see default_caps_with_cpu()).
> + */
> + smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 0;
> }
>
> DEFINE_SPAPR_MACHINE(2_12, "2.12", false);
> diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> index 62663ebdf51a..aa605cea9108 100644
> --- a/hw/ppc/spapr_caps.c
> +++ b/hw/ppc/spapr_caps.c
> @@ -465,6 +465,19 @@ static sPAPRCapabilities
> default_caps_with_cpu(sPAPRMachineState *spapr,
> caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_BROKEN;
> }
>
> + /* This is for pseries-2.12 and older */
> + if (smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] == 0) {
> + 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 */
> + }
> +
> + caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = mps;
> + }
> +
> return caps;
> }
>
>
--
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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