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-rw-r--r--hw/i386/acpi-build.c57
-rw-r--r--hw/i386/pc_piix.c19
-rw-r--r--hw/i386/pc_q35.c5
3 files changed, 77 insertions, 4 deletions
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index ebc5f034e3..d90c471792 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -25,7 +25,9 @@
#include <glib.h>
#include "qemu-common.h"
#include "qemu/bitmap.h"
+#include "qemu/osdep.h"
#include "qemu/range.h"
+#include "qemu/error-report.h"
#include "hw/pci/pci.h"
#include "qom/cpu.h"
#include "hw/i386/pc.h"
@@ -52,6 +54,14 @@
#include "qapi/qmp/qint.h"
#include "qom/qom-qobject.h"
+/* These are used to size the ACPI tables for -M pc-i440fx-1.7 and
+ * -M pc-i440fx-2.0. Even if the actual amount of AML generated grows
+ * a little bit, there should be plenty of free space since the DSDT
+ * shrunk by ~1.5k between QEMU 2.0 and QEMU 2.1.
+ */
+#define ACPI_BUILD_LEGACY_CPU_AML_SIZE 97
+#define ACPI_BUILD_ALIGN_SIZE 0x1000
+
typedef struct AcpiCpuInfo {
DECLARE_BITMAP(found_cpus, ACPI_CPU_HOTPLUG_ID_LIMIT);
} AcpiCpuInfo;
@@ -1440,13 +1450,14 @@ static
void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
{
GArray *table_offsets;
- unsigned facs, dsdt, rsdt;
+ unsigned facs, ssdt, dsdt, rsdt;
AcpiCpuInfo cpu;
AcpiPmInfo pm;
AcpiMiscInfo misc;
AcpiMcfgInfo mcfg;
PcPciInfo pci;
uint8_t *u;
+ size_t aml_len = 0;
acpi_get_cpu_info(&cpu);
acpi_get_pm_info(&pm);
@@ -1474,13 +1485,20 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
dsdt = tables->table_data->len;
build_dsdt(tables->table_data, tables->linker, &misc);
+ /* Count the size of the DSDT and SSDT, we will need it for legacy
+ * sizing of ACPI tables.
+ */
+ aml_len += tables->table_data->len - dsdt;
+
/* ACPI tables pointed to by RSDT */
acpi_add_table(table_offsets, tables->table_data);
build_fadt(tables->table_data, tables->linker, &pm, facs, dsdt);
+ ssdt = tables->table_data->len;
acpi_add_table(table_offsets, tables->table_data);
build_ssdt(tables->table_data, tables->linker, &cpu, &pm, &misc, &pci,
guest_info);
+ aml_len += tables->table_data->len - ssdt;
acpi_add_table(table_offsets, tables->table_data);
build_madt(tables->table_data, tables->linker, &cpu, guest_info);
@@ -1513,14 +1531,45 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
/* RSDP is in FSEG memory, so allocate it separately */
build_rsdp(tables->rsdp, tables->linker, rsdt);
- /* We'll expose it all to Guest so align size to reduce
+ /* We'll expose it all to Guest so we want to reduce
* chance of size changes.
* RSDP is small so it's easy to keep it immutable, no need to
* bother with alignment.
+ *
+ * We used to align the tables to 4k, but of course this would
+ * too simple to be enough. 4k turned out to be too small an
+ * alignment very soon, and in fact it is almost impossible to
+ * keep the table size stable for all (max_cpus, max_memory_slots)
+ * combinations. So the table size is always 64k for pc-i440fx-2.1
+ * and we give an error if the table grows beyond that limit.
+ *
+ * We still have the problem of migrating from "-M pc-i440fx-2.0". For
+ * that, we exploit the fact that QEMU 2.1 generates _smaller_ tables
+ * than 2.0 and we can always pad the smaller tables with zeros. We can
+ * then use the exact size of the 2.0 tables.
+ *
+ * All this is for PIIX4, since QEMU 2.0 didn't support Q35 migration.
*/
- acpi_align_size(tables->table_data, 0x1000);
+ if (guest_info->legacy_acpi_table_size) {
+ /* Subtracting aml_len gives the size of fixed tables. Then add the
+ * size of the PIIX4 DSDT/SSDT in QEMU 2.0.
+ */
+ int legacy_aml_len =
+ guest_info->legacy_acpi_table_size +
+ ACPI_BUILD_LEGACY_CPU_AML_SIZE * max_cpus;
+ int legacy_table_size =
+ ROUND_UP(tables->table_data->len - aml_len + legacy_aml_len,
+ ACPI_BUILD_ALIGN_SIZE);
+ if (tables->table_data->len > legacy_table_size) {
+ /* Should happen only with PCI bridges and -M pc-i440fx-2.0. */
+ error_report("Warning: migration to QEMU 2.0 may not work.");
+ }
+ g_array_set_size(tables->table_data, legacy_table_size);
+ } else {
+ acpi_align_size(tables->table_data, ACPI_BUILD_ALIGN_SIZE);
+ }
- acpi_align_size(tables->linker, 0x1000);
+ acpi_align_size(tables->linker, ACPI_BUILD_ALIGN_SIZE);
/* Cleanup memory that's no longer used. */
g_array_free(table_offsets, true);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 7081c08a69..4524e6b56e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -61,6 +61,7 @@ static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
static bool has_pci_info;
static bool has_acpi_build = true;
+static int legacy_acpi_table_size;
static bool smbios_defaults = true;
static bool smbios_legacy_mode;
/* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to
@@ -163,6 +164,7 @@ static void pc_init1(MachineState *machine,
guest_info = pc_guest_info_init(below_4g_mem_size, above_4g_mem_size);
guest_info->has_acpi_build = has_acpi_build;
+ guest_info->legacy_acpi_table_size = legacy_acpi_table_size;
guest_info->has_pci_info = has_pci_info;
guest_info->isapc_ram_fw = !pci_enabled;
@@ -297,6 +299,23 @@ static void pc_init_pci(MachineState *machine)
static void pc_compat_2_0(MachineState *machine)
{
+ /* This value depends on the actual DSDT and SSDT compiled into
+ * the source QEMU; unfortunately it depends on the binary and
+ * not on the machine type, so we cannot make pc-i440fx-1.7 work on
+ * both QEMU 1.7 and QEMU 2.0.
+ *
+ * Large variations cause migration to fail for more than one
+ * consecutive value of the "-smp" maxcpus option.
+ *
+ * For small variations of the kind caused by different iasl versions,
+ * the 4k rounding usually leaves slack. However, there could be still
+ * one or two values that break. For QEMU 1.7 and QEMU 2.0 the
+ * slack is only ~10 bytes before one "-smp maxcpus" value breaks!
+ *
+ * 6652 is valid for QEMU 2.0, the right value for pc-i440fx-1.7 on
+ * QEMU 1.7 it is 6414. For RHEL/CentOS 7.0 it is 6418.
+ */
+ legacy_acpi_table_size = 6652;
smbios_legacy_mode = true;
has_reserved_memory = false;
}
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index f55196150c..c39ee98933 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -155,6 +155,11 @@ static void pc_q35_init(MachineState *machine)
guest_info->has_acpi_build = has_acpi_build;
guest_info->has_reserved_memory = has_reserved_memory;
+ /* Migration was not supported in 2.0 for Q35, so do not bother
+ * with this hack (see hw/i386/acpi-build.c).
+ */
+ guest_info->legacy_acpi_table_size = 0;
+
if (smbios_defaults) {
MachineClass *mc = MACHINE_GET_CLASS(machine);
/* These values are guest ABI, do not change */
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-29 15:23:10 +0000