Add padding after the DSDT. Tables that vary depending on the command-line arguments will have to be byte-equivalent across QEMU versions >= 2.2, while fixed tables (including the DSDT) can be changed freely.
This new algorithm will let us present smaller ACPI blobs to the guest, which avoids bugs with -kernel/-initrd and 32-bit RHEL5 guests. However, this patch does not change the size of the blobs yet; for now, the values of the parameters are tuned to have 2.1-compatible sizes. Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> --- hw/i386/acpi-build.c | 11 +++++++---- hw/i386/pc_piix.c | 5 +++++ include/hw/i386/pc.h | 2 ++ 3 files changed, 14 insertions(+), 4 deletions(-) diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 694ee91..48e7f2e 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -65,8 +65,6 @@ #define ACPI_BUILD_LEGACY_CPU_AML_SIZE 97 #define ACPI_BUILD_ALIGN_SIZE 0x1000 -#define ACPI_BUILD_TABLE_SIZE 0x20000 - typedef struct AcpiCpuInfo { DECLARE_BITMAP(found_cpus, ACPI_CPU_HOTPLUG_ID_LIMIT); } AcpiCpuInfo; @@ -1597,6 +1595,10 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables) acpi_add_table(table_offsets, tables->table_data); build_fadt(tables->table_data, tables->linker, &pm, facs, dsdt); + if (guest_info->fixed_table_align) { + acpi_align_size(tables->table_data, guest_info->fixed_table_align); + } + ssdt = tables->table_data->len; acpi_add_table(table_offsets, tables->table_data); build_ssdt(tables->table_data, tables->linker, &cpu, &pm, &misc, &pci, @@ -1681,14 +1683,15 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables) g_array_set_size(tables->table_data, legacy_table_size); } else { /* Make sure we have a buffer in case we need to resize the tables. */ - if (tables->table_data->len > ACPI_BUILD_TABLE_SIZE / 2) { + if (!guest_info->fixed_table_align && + tables->table_data->len > guest_info->acpi_table_align / 2) { /* As of QEMU 2.1, this fires with 160 VCPUs and 255 memory slots. */ error_report("Warning: ACPI tables are larger than 64k."); error_report("Warning: migration may not work."); error_report("Warning: please remove CPUs, NUMA nodes, " "memory slots or PCI bridges."); } - acpi_align_size(tables->table_data, ACPI_BUILD_TABLE_SIZE); + acpi_align_size(tables->table_data, guest_info->acpi_table_align); } pc_set_acpi_data_size(tables->table_data->len); diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index ca9f07c..1ecb281 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -61,6 +61,8 @@ static const int ide_irq[MAX_IDE_BUS] = { 14, 15 }; static bool has_acpi_build = true; static int legacy_acpi_table_size; +static int fixed_table_align = 0; +static int acpi_table_align = 131072; static bool smbios_defaults = true; static bool smbios_legacy_mode; /* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to @@ -164,6 +166,8 @@ static void pc_init1(MachineState *machine, guest_info->has_acpi_build = has_acpi_build; guest_info->legacy_acpi_table_size = legacy_acpi_table_size; + guest_info->fixed_table_align = fixed_table_align; + guest_info->acpi_table_align = acpi_table_align; guest_info->isapc_ram_fw = !pci_enabled; guest_info->has_reserved_memory = has_reserved_memory; @@ -314,6 +318,7 @@ static void pc_compat_2_0(MachineState *machine) * QEMU 1.7 it is 6414. For RHEL/CentOS 7.0 it is 6418. */ legacy_acpi_table_size = 6652; + acpi_table_align = 4096; smbios_legacy_mode = true; has_reserved_memory = false; } diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 853829b..8b65b47 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -94,6 +94,8 @@ struct PcGuestInfo { uint64_t *node_cpu; FWCfgState *fw_cfg; int legacy_acpi_table_size; + int fixed_table_align; + int acpi_table_align; bool has_acpi_build; bool has_reserved_memory; }; -- 2.1.0