From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45951) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNSSr-0005tA-7n for qemu-devel@nongnu.org; Wed, 13 Jul 2016 18:17:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bNSSk-0007h7-AX for qemu-devel@nongnu.org; Wed, 13 Jul 2016 18:17:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43732) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNSSk-0007h3-2k for qemu-devel@nongnu.org; Wed, 13 Jul 2016 18:17:02 -0400 From: Bandan Das References: <1467786055-85835-1-git-send-email-imammedo@redhat.com> <1467786055-85835-5-git-send-email-imammedo@redhat.com> Date: Wed, 13 Jul 2016 18:16:59 -0400 In-Reply-To: <1467786055-85835-5-git-send-email-imammedo@redhat.com> (Igor Mammedov's message of "Wed, 6 Jul 2016 08:20:40 +0200") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH v3 04/19] pc: cpu: consolidate apic-id validity checks in pc_cpu_pre_plug() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, pkrempa@redhat.com, ehabkost@redhat.com, mst@redhat.com, armbru@redhat.com, eduardo.otubo@profitbricks.com, marcel@redhat.com, pbonzini@redhat.com, rth@twiddle.net Igor Mammedov writes: > Machine code knows about all possible APIC IDs so use that > instead of hack which does O(n^2) complexity duplicate > checks, interating over global CPUs list. > As result duplicate check is done only once with O(log n) complexity. > > Signed-off-by: Igor Mammedov > --- > hw/i386/pc.c | 44 ++++++++++++++++++++++++++++++++------------ > target-i386/cpu.c | 13 ------------- > 2 files changed, 32 insertions(+), 25 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 3c42d84..99dfbe0 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1071,18 +1071,6 @@ void pc_hot_add_cpu(const int64_t id, Error **errp) > return; > } > > - if (cpu_exists(apic_id)) { > - error_setg(errp, "Unable to add CPU: %" PRIi64 > - ", it already exists", id); > - return; > - } > - > - if (id >= max_cpus) { > - error_setg(errp, "Unable to add CPU: %" PRIi64 > - ", max allowed: %d", id, max_cpus - 1); > - return; > - } > - > if (apic_id >= ACPI_CPU_HOTPLUG_ID_LIMIT) { > error_setg(errp, "Unable to add CPU: %" PRIi64 > ", resulting APIC ID (%" PRIi64 ") is too large", > @@ -1771,6 +1759,37 @@ static void pc_cpu_unplug_cb(HotplugHandler *hotplug_dev, > error_propagate(errp, local_err); > } > > +static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + int idx; > + X86CPU *cpu = X86_CPU(dev); > + PCMachineState *pcms = PC_MACHINE(hotplug_dev); > + CPUArchId *cpu_slot = pc_find_cpu_slot(pcms, CPU(dev), &idx); > + > + if (!cpu_slot) { > + error_setg(errp, "Invalid CPU index with APIC ID (%" PRIu32 > + "), valid range 0:%d", cpu->apic_id, > + pcms->possible_cpus->len - 1); > + return; > + } > + > + if (cpu_slot->cpu) { > + error_setg(errp, "CPU[%ld] with APIC ID %" PRIu32 " exists", > + cpu_slot - pcms->possible_cpus->cpus, > + cpu->apic_id); > + return; > + } > +} > + > +static void pc_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) { > + pc_cpu_pre_plug(hotplug_dev, dev, errp); > + } > +} > Will this path be invoked for non TYPE_CPU callbacks too ? I was just wondering if there should be an "else" error message. Bandan > static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev, > DeviceState *dev, Error **errp) > { > @@ -2068,6 +2087,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) > mc->hot_add_cpu = pc_hot_add_cpu; > mc->max_cpus = 255; > mc->reset = pc_machine_reset; > + hc->pre_plug = pc_machine_device_pre_plug_cb; > hc->plug = pc_machine_device_plug_cb; > hc->unplug_request = pc_machine_device_unplug_request_cb; > hc->unplug = pc_machine_device_unplug_cb; > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > index e7319e3..9511474 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -1838,8 +1838,6 @@ static void x86_cpuid_set_apic_id(Object *obj, Visitor *v, const char *name, > { > X86CPU *cpu = X86_CPU(obj); > DeviceState *dev = DEVICE(obj); > - const int64_t min = 0; > - const int64_t max = UINT32_MAX; > Error *error = NULL; > int64_t value; > > @@ -1854,17 +1852,6 @@ static void x86_cpuid_set_apic_id(Object *obj, Visitor *v, const char *name, > error_propagate(errp, error); > return; > } > - if (value < min || value > max) { > - error_setg(errp, "Property %s.%s doesn't take value %" PRId64 > - " (minimum: %" PRId64 ", maximum: %" PRId64 ")" , > - object_get_typename(obj), name, value, min, max); > - return; > - } > - > - if ((value != cpu->apic_id) && cpu_exists(value)) { > - error_setg(errp, "CPU with APIC ID %" PRIi64 " exists", value); > - return; > - } > cpu->apic_id = value; > }