From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36741) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRj22-0006Ai-I3 for qemu-devel@nongnu.org; Fri, 05 Feb 2016 11:14:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aRj1x-0005Sh-Gd for qemu-devel@nongnu.org; Fri, 05 Feb 2016 11:14:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50429) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRj1x-0005SS-8b for qemu-devel@nongnu.org; Fri, 05 Feb 2016 11:14:45 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 5AEBA3798BC for ; Fri, 5 Feb 2016 16:14:44 +0000 (UTC) Date: Fri, 5 Feb 2016 17:14:41 +0100 From: Igor Mammedov Message-ID: <20160205171441.4d5e8b12@nial.brq.redhat.com> In-Reply-To: <20160205152831.GR26314@thinpad.lan.raisama.net> References: <1454586455-10202-1-git-send-email-imammedo@redhat.com> <1454586455-10202-6-git-send-email-imammedo@redhat.com> <20160205152831.GR26314@thinpad.lan.raisama.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 6/9] pc: acpi: create MADT.lapic entries only for valid lapics List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, mst@redhat.com On Fri, 5 Feb 2016 13:28:31 -0200 Eduardo Habkost wrote: > On Thu, Feb 04, 2016 at 12:47:32PM +0100, Igor Mammedov wrote: > > do not assume that all lapics in range 0..apic_id_limit > > are valid and do not create lapic entries for not > > possible lapics in MADT. > > > > Signed-off-by: Igor Mammedov > > Reviewed-by: Eduardo Habkost > > But there's one minor suggestion below: > > > --- > > hw/i386/acpi-build.c | 21 ++++++++++++++------- > > 1 file changed, 14 insertions(+), 7 deletions(-) > > > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c > > index df13c7d..9eeeffa 100644 > > --- a/hw/i386/acpi-build.c > > +++ b/hw/i386/acpi-build.c > > @@ -361,9 +361,11 @@ build_fadt(GArray *table_data, GArray *linker, AcpiPmInfo *pm, > > } > > > > static void > > -build_madt(GArray *table_data, GArray *linker, AcpiCpuInfo *cpu, > > - PcGuestInfo *guest_info) > > +build_madt(GArray *table_data, GArray *linker, > > + MachineState *machine, PcGuestInfo *guest_info) > > { > > + MachineClass *mc = MACHINE_GET_CLASS(machine); > > + GArray *apic_id_list = mc->possible_cpu_arch_ids(); > > int madt_start = table_data->len; > > > > AcpiMultipleApicTable *madt; > > @@ -376,18 +378,23 @@ build_madt(GArray *table_data, GArray *linker, AcpiCpuInfo *cpu, > > madt->local_apic_address = cpu_to_le32(APIC_DEFAULT_ADDRESS); > > madt->flags = cpu_to_le32(1); > > > > - for (i = 0; i < guest_info->apic_id_limit; i++) { > > + for (i = 0; i < apic_id_list->len; i++) { > > AcpiMadtProcessorApic *apic = acpi_data_push(table_data, sizeof *apic); > > + CPUArchId id = FETCH_CPU_ARCH_ID(apic_id_list, i); > > + int apic_id = id.arch_id; > > + > > apic->type = ACPI_APIC_PROCESSOR; > > apic->length = sizeof(*apic); > > - apic->processor_id = i; > > - apic->local_apic_id = i; > > - if (test_bit(i, cpu->found_cpus)) { > > + apic->processor_id = apic_id; > > + apic->local_apic_id = apic_id; > > + if (id.cpu != NULL) { > > This seems to be the only place where CPUArchId.cpu is being used > (see my previous suggestion about making possible_cpu_arch_ids() > return just an uint64_t list). > > Also, using the existing found_cpus bitmap is more efficient than > making multiple calls to qemu_get_cpu_by_arch_id(). I wouldn't > mind keeping the bitmap. found_cpus bitmap is not better than (id.cpu != NULL) check the cost of filling both is about the same. The issue I have with bitmap is that it's harder to generalize CPU hotplug code with it, while with possible_cpu_arch_ids() returned array I have a list of CPUs to work with without any assumptions on position in bitmap or array. Also bitmap scales worse than a list of CPUs if ID space is sparse and if ID is quite big. That's why I'm dropping bitmap and switching to a list of IDs which in worst case is upto max_cpus. > > > apic->flags = cpu_to_le32(1); > > } else { > > apic->flags = cpu_to_le32(0); > > } > > } > > + g_array_free(apic_id_list, true); > > + > > io_apic = acpi_data_push(table_data, sizeof *io_apic); > > io_apic->type = ACPI_APIC_IO; > > io_apic->length = sizeof(*io_apic); > > @@ -2659,7 +2666,7 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables) > > aml_len += tables_blob->len - fadt; > > > > acpi_add_table(table_offsets, tables_blob); > > - build_madt(tables_blob, tables->linker, &cpu, guest_info); > > + build_madt(tables_blob, tables->linker, machine, guest_info); > > > > if (misc.has_hpet) { > > acpi_add_table(table_offsets, tables_blob); > > -- > > 1.8.3.1 > > >