From e89372951d328143ecdb3a524bf53454ad9309b0 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Mon, 2 Jul 2018 10:54:56 +0200 Subject: [PATCH] spapr: compute default value of "hpt-max-page-size" later 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 Reviewed-by: Eduardo Habkost Signed-off-by: David Gibson --- 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 b2baec026f..062d9dc346 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 62663ebdf5..aa605cea91 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; }