From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58393) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1afqUe-0001wl-TN for qemu-devel@nongnu.org; Tue, 15 Mar 2016 11:02:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1afqUa-0007Hv-PH for qemu-devel@nongnu.org; Tue, 15 Mar 2016 11:02:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44543) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1afqUa-0007Hi-Jg for qemu-devel@nongnu.org; Tue, 15 Mar 2016 11:02:40 -0400 Date: Tue, 15 Mar 2016 17:02:36 +0200 From: "Michael S. Tsirkin" Message-ID: <1458053975-2410-41-git-send-email-mst@redhat.com> References: <1458053975-2410-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1458053975-2410-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL v2 40/51] 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: Peter Maydell , Richard Henderson , Paolo Bonzini , Eduardo Habkost , Igor Mammedov From: Igor Mammedov Signed-off-by: Igor Mammedov Reviewed-by: Eduardo Habkost Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- 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 8736917..0a5acb3 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -360,6 +360,12 @@ 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); } } -- MST