From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Mammedov Subject: Re: [Qemu-devel] [PATCH] target-i386: Sanity check host processor physical address width Date: Thu, 9 Jul 2015 14:51:05 +0200 Message-ID: <20150709145105.1c533e4c@nial.brq.redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, Paolo Bonzini , Laszlo Ersek , Eduardo Habkost , kvm@vger.kernel.org To: Bandan Das Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51181 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752593AbbGIMvI (ORCPT ); Thu, 9 Jul 2015 08:51:08 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Wed, 08 Jul 2015 18:42:01 -0400 Bandan Das wrote: > > If a Linux guest is assigned more memory than is supported > by the host processor, the guest is unable to boot. That > is expected, however, there's no message indicating the user > what went wrong. This change prints a message to stderr if > KVM has the corresponding capability. > > Reported-by: Laszlo Ersek > Signed-off-by: Bandan Das > --- > linux-headers/linux/kvm.h | 1 + > target-i386/kvm.c | 6 ++++++ > 2 files changed, 7 insertions(+) > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h > index 3bac873..6afad49 100644 > --- a/linux-headers/linux/kvm.h > +++ b/linux-headers/linux/kvm.h > @@ -817,6 +817,7 @@ struct kvm_ppc_smmu_info { > #define KVM_CAP_DISABLE_QUIRKS 116 > #define KVM_CAP_X86_SMM 117 > #define KVM_CAP_MULTI_ADDRESS_SPACE 118 > +#define KVM_CAP_PHY_ADDR_WIDTH 119 > > #ifdef KVM_CAP_IRQ_ROUTING > > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > index 066d03d..66e3448 100644 > --- a/target-i386/kvm.c > +++ b/target-i386/kvm.c > @@ -892,6 +892,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > uint64_t shadow_mem; > int ret; > struct utsname utsname; > + int max_phys_bits; > > ret = kvm_get_supported_msrs(s); > if (ret < 0) { > @@ -945,6 +946,11 @@ int kvm_arch_init(MachineState *ms, KVMState *s) > } > } > > + max_phys_bits = kvm_check_extension(s, KVM_CAP_PHY_ADDR_WIDTH); max_phys_bits seems generic enough and could be applied to other targets as well. making it a property of machine, would make accessing/manipulating it easier. define default value for machine/TCG mode and when KVM is enabled it would override/set its own limit. then any board could easily access machine->max_gpa to make board specific checks. > + if (max_phys_bits && (1ULL << max_phys_bits) <= ram_size) > + fprintf(stderr, "Warning: The amount of memory assigned to the guest " > + "is more than that supported by the host CPU(s). Guest may be unstable.\n"); > + > if (kvm_check_extension(s, KVM_CAP_X86_SMM)) { > smram_machine_done.notify = register_smram_listener; > qemu_add_machine_init_done_notifier(&smram_machine_done);