From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:47745) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T6RE5-0005Hg-LK for qemu-devel@nongnu.org; Tue, 28 Aug 2012 15:13:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T6RE4-0003ek-6r for qemu-devel@nongnu.org; Tue, 28 Aug 2012 15:13:25 -0400 Received: from mail-ob0-f173.google.com ([209.85.214.173]:32829) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T6RE4-0003ed-0R for qemu-devel@nongnu.org; Tue, 28 Aug 2012 15:13:24 -0400 Received: by obbta14 with SMTP id ta14so10499838obb.4 for ; Tue, 28 Aug 2012 12:13:22 -0700 (PDT) From: Anthony Liguori In-Reply-To: <246329d9a275f3735aeaeab9326b1527330fe13a.1346069810.git.mst@redhat.com> References: <246329d9a275f3735aeaeab9326b1527330fe13a.1346069810.git.mst@redhat.com> Date: Tue, 28 Aug 2012 14:13:18 -0500 Message-ID: <87d32abzjl.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: Re: [Qemu-devel] [PATCHv2 3/4] cpuid: disable pv eoi for 1.1 and older compat types List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , avi@redhat.com, mtosatti@redhat.com, gleb@redhat.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, Jan Kiszka "Michael S. Tsirkin" writes: > In preparation for adding PV EOI support, disable PV EOI by default for > 1.1 and older machine types, to avoid CPUID changing during migration. > > PV EOI can still be enabled/disabled by specifying it explicitly. > Enable for 1.1 > -M pc-1.1 -cpu kvm64,+kvm_pv_eoi > Disable for 1.2 > -M pc-1.2 -cpu kvm64,-kvm_pv_eoi > > Signed-off-by: Michael S. Tsirkin > --- > hw/Makefile.objs | 2 +- > hw/cpu_flags.c | 32 ++++++++++++++++++++++++++++++++ > hw/cpu_flags.h | 9 +++++++++ > hw/pc_piix.c | 2 ++ > target-i386/cpu.c | 8 ++++++++ > 5 files changed, 52 insertions(+), 1 deletion(-) > create mode 100644 hw/cpu_flags.c > create mode 100644 hw/cpu_flags.h > > diff --git a/hw/Makefile.objs b/hw/Makefile.objs > index 850b87b..3f2532a 100644 > --- a/hw/Makefile.objs > +++ b/hw/Makefile.objs > @@ -1,5 +1,5 @@ > hw-obj-y = usb/ ide/ > -hw-obj-y += loader.o > +hw-obj-y += loader.o cpu_flags.o > hw-obj-$(CONFIG_VIRTIO) += virtio-console.o > hw-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o > hw-obj-y += fw_cfg.o > diff --git a/hw/cpu_flags.c b/hw/cpu_flags.c > new file mode 100644 > index 0000000..2422d20 > --- /dev/null > +++ b/hw/cpu_flags.c > @@ -0,0 +1,32 @@ > +/* > + * CPU compatibility flags. > + * > + * Copyright (c) 2012 Red Hat Inc. > + * Author: Michael S. Tsirkin. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License along > + * with this program; if not, see . > + */ > +#include "hw/cpu_flags.h" > + > +static bool __kvm_pv_eoi_disabled; > + > +void disable_kvm_pv_eoi(void) > +{ > + __kvm_pv_eoi_disabled = true; > +} > + > +bool kvm_pv_eoi_disabled(void) > +{ > + return __kvm_pv_eoi_disabled; > +} Would this make more sense as a CPU flag or at least the KVM PV LAPIC? We really ought to embed the LAPIC in the CPU objects. Then it would all make a bit more sense conceptionally. But I definitely thing a CPU feature flag makes the most sense here. Then we can handle it via globals once we make CPU's qdev devices. Regards, Anthony Liguori > diff --git a/hw/cpu_flags.h b/hw/cpu_flags.h > new file mode 100644 > index 0000000..05777b6 > --- /dev/null > +++ b/hw/cpu_flags.h > @@ -0,0 +1,9 @@ > +#ifndef HW_CPU_FLAGS_H > +#define HW_CPU_FLAGS_H > + > +#include > + > +void disable_kvm_pv_eoi(void); > +bool kvm_pv_eoi_disabled(void); > + > +#endif > diff --git a/hw/pc_piix.c b/hw/pc_piix.c > index 008d42f..bdbceda 100644 > --- a/hw/pc_piix.c > +++ b/hw/pc_piix.c > @@ -46,6 +46,7 @@ > #ifdef CONFIG_XEN > # include > #endif > +#include "cpu_flags.h" > > #define MAX_IDE_BUS 2 > > @@ -371,6 +372,7 @@ static QEMUMachine pc_machine_v1_2 = { > > static void pc_machine_v1_1_compat(void) > { > + disable_kvm_pv_eoi(); > } > > static void pc_init_pci_v1_1(ram_addr_t ram_size, > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > index 120a2e3..0d02fd1 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -23,6 +23,7 @@ > > #include "cpu.h" > #include "kvm.h" > +#include "asm/kvm_para.h" > > #include "qemu-option.h" > #include "qemu-config.h" > @@ -33,6 +34,7 @@ > #include "hyperv.h" > > #include "hw/hw.h" > +#include "hw/cpu_flags.h" > > /* feature flags taken from "Intel Processor Identification and the CPUID > * Instruction" and AMD's "CPUID Specification". In cases of disagreement > @@ -889,6 +891,12 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model) > > plus_kvm_features = ~0; /* not supported bits will be filtered out later */ > > + /* Disable PV EOI for old machine types. > + * Feature flags can still override. */ > + if (kvm_pv_eoi_disabled()) { > + plus_kvm_features &= ~(0x1 << KVM_FEATURE_PV_EOI); > + } > + > add_flagname_to_bitmaps("hypervisor", &plus_features, > &plus_ext_features, &plus_ext2_features, &plus_ext3_features, > &plus_kvm_features, &plus_svm_features); > -- > MST