From 26297cc34474a57f0a6d845ed71511efb64ec1a1 Mon Sep 17 00:00:00 2001 Message-Id: <26297cc34474a57f0a6d845ed71511efb64ec1a1.1418787305.git.jen@redhat.com> In-Reply-To: References: From: Eduardo Habkost Date: Fri, 12 Dec 2014 16:53:22 -0600 Subject: [CHANGE 12/12] acpi: Use apic_id_limit when calculating legacy ACPI table size To: rhvirt-patches@redhat.com, jen@redhat.com RH-Author: Eduardo Habkost Message-id: <1418403202-5444-1-git-send-email-ehabkost@redhat.com> Patchwork-id: 62851 O-Subject: [RHEV-7.1 qemu-kvm-rhev PATCH] acpi: Use apic_id_limit when calculating legacy ACPI table size Bugzilla: 1173167 RH-Acked-by: Paolo Bonzini RH-Acked-by: Igor Mammedov RH-Acked-by: Laszlo Ersek The code that calculates the legacy ACPI table size for migration compatibility uses max_cpus when calculating legacy_aml_len (the size of the DSDT and SSDT tables). However, the SSDT grows according to APIC ID limit, not max_cpus. The bug is not triggered very often because of the 4k alignment on the table size. But it can be triggered if you are unlucky enough to cross a 4k boundary. For example, using the following: $ qemu-system-x86_64 -machine pc-i440fx-2.0 -smp 99,sockets=3,cores=33,threads=1 qemu-system-x86_64: Warning: migration may not work. Change the legacy_aml_len calculation to use apic_id_limit, to calculate the right size. Signed-off-by: Eduardo Habkost Signed-off-by: Jeff E. Nelson --- hw/i386/acpi-build.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 8609871..33cdd4d 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -1586,7 +1586,7 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables) */ int legacy_aml_len = guest_info->legacy_acpi_table_size + - ACPI_BUILD_LEGACY_CPU_AML_SIZE * max_cpus; + ACPI_BUILD_LEGACY_CPU_AML_SIZE * guest_info->apic_id_limit; int legacy_table_size = ROUND_UP(tables->table_data->len - aml_len + legacy_aml_len, ACPI_BUILD_ALIGN_SIZE); -- 2.1.0