From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60699) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aYFTj-0004p7-8I for qemu-devel@nongnu.org; Tue, 23 Feb 2016 11:06:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aYFTi-0003Gb-A6 for qemu-devel@nongnu.org; Tue, 23 Feb 2016 11:06:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57792) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aYFTi-0003Fm-5z for qemu-devel@nongnu.org; Tue, 23 Feb 2016 11:06:22 -0500 From: Igor Mammedov Date: Tue, 23 Feb 2016 17:06:00 +0100 Message-Id: <1456243560-67516-9-git-send-email-imammedo@redhat.com> In-Reply-To: <1456243560-67516-1-git-send-email-imammedo@redhat.com> References: <1456243560-67516-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v3 8/8] pc: acpi: clarify why possible LAPIC entries must be present in MADT List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: ehabkost@redhat.com, mst@redhat.com, marcel.apfelbaum@gmail.com, Paolo Bonzini , Igor Mammedov , Richard Henderson Signed-off-by: Igor Mammedov Reviewed-by: Eduardo Habkost --- hw/i386/acpi-build.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index e66c8b7..534a855 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -361,6 +361,12 @@ build_madt(GArray *table_data, GArray *linker, PCMachineState *pcms) if (apic_ids->cpus[i].cpu != NULL) { apic->flags = cpu_to_le32(1); } else { + /* ACPI spec says that LAPIC entry for non present + * CPU may be omitted from MADT or it must be marked + * as disabled. However omitting non present CPU from + * MADT breaks hotplug on linux. So possible CPUs + * should be put in MADT but kept disabled. + */ apic->flags = cpu_to_le32(0); } } -- 1.8.3.1