[Qemu-devel] [PATCH 2/2] pc: acpi-build: make linker & RSDP tables dynamic

[Igor Mammedov <imammedo@redhat.com>]

linker and RSDP tables are build only once, so if later
during rebuild sizes of other ACPI tables change
pointers will be patched incorrectly due to wrong
offsets.

To fix it rebuild linker and RSDP tables along with
the rest of ACPI tables so that they would have correct
offsets.

Here is a simple reproducer:
 1: hotplug bridge using command:
     device_add pci-bridge,chassis_nr=1
 2: reset system from monitor:
     system_reset

As result pointers to ACPI tables are not correct
and guest can't read/parse ACPI tables.

Windows guests just refuse to boot and
Linux guests are more resilient and try to boot without
ACPI, sometimes successfully.

PS:
 keep brokenness in 2.2 and older machine types for the sake
 of migration

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
Tested backwards migration from QEMU 2.3 to 2.2 with
pc-i440fx-2.2 machine type

 hw/i386/acpi-build.c | 30 +++++++++++++++++++++++-------
 hw/i386/pc_piix.c    |  3 +++
 hw/i386/pc_q35.c     |  3 +++
 include/hw/i386/pc.h |  1 +
 4 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b37a397..4d2452d 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1509,6 +1509,10 @@ struct AcpiBuildState {
     /* Copy of table in RAM (for patching). */
     ram_addr_t table_ram;
     uint32_t table_size;
+    ram_addr_t linker_ram;
+    uint32_t linker_size;
+    ram_addr_t rsdp_ram;
+    uint32_t rsdp_size;
     /* Is table patched? */
     uint8_t patched;
     PcGuestInfo *guest_info;
@@ -1714,6 +1718,10 @@ static void acpi_build_update(void *build_opaque, uint32_t offset)
     assert(acpi_data_len(tables.table_data) == build_state->table_size);
     memcpy(qemu_get_ram_ptr(build_state->table_ram), tables.table_data->data,
            build_state->table_size);
+    memcpy(qemu_get_ram_ptr(build_state->linker_ram), tables.linker->data,
+           build_state->linker_size);
+    memcpy(qemu_get_ram_ptr(build_state->rsdp_ram), tables.rsdp->data,
+           build_state->rsdp_size);
 
     cpu_physical_memory_set_dirty_range_nocode(build_state->table_ram,
                                                build_state->table_size);
@@ -1779,17 +1787,25 @@ void acpi_setup(PcGuestInfo *guest_info)
     assert(build_state->table_ram != RAM_ADDR_MAX);
     build_state->table_size = acpi_data_len(tables.table_data);
 
-    acpi_add_rom_blob(NULL, tables.linker, "etc/table-loader");
+    build_state->linker_ram = acpi_add_rom_blob(build_state, tables.linker,
+                                                "etc/table-loader");
+    build_state->linker_size = acpi_data_len(tables.linker);
 
     fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
                     tables.tcpalog->data, acpi_data_len(tables.tcpalog));
 
-    /*
-     * RSDP is small so it's easy to keep it immutable, no need to
-     * bother with ROM blobs.
-     */
-    fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
-                    tables.rsdp->data, acpi_data_len(tables.rsdp));
+    if (guest_info->has_imutable_rsdp) {
+        /*
+         * RSDP is small so it's easy to keep it immutable, no need to
+         * bother with ROM blobs.
+         */
+        fw_cfg_add_file(guest_info->fw_cfg, ACPI_BUILD_RSDP_FILE,
+                        tables.rsdp->data, acpi_data_len(tables.rsdp));
+    } else {
+        build_state->rsdp_ram = acpi_add_rom_blob(build_state, tables.rsdp,
+                                                  ACPI_BUILD_RSDP_FILE);
+        build_state->rsdp_size = acpi_data_len(tables.rsdp);
+    }
 
     qemu_register_reset(acpi_build_reset, build_state);
     acpi_build_reset(build_state);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 685fa54..69d4de2 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -60,6 +60,7 @@ static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 0x376 };
 static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 
 static bool has_acpi_build = true;
+static bool has_imutable_rsdp;
 static int legacy_acpi_table_size;
 static bool smbios_defaults = true;
 static bool smbios_legacy_mode;
@@ -168,6 +169,7 @@ static void pc_init1(MachineState *machine,
 
     guest_info->isapc_ram_fw = !pci_enabled;
     guest_info->has_reserved_memory = has_reserved_memory;
+    guest_info->has_imutable_rsdp = has_imutable_rsdp;
 
     if (smbios_defaults) {
         MachineClass *mc = MACHINE_GET_CLASS(machine);
@@ -310,6 +312,7 @@ static void pc_init_pci(MachineState *machine)
 
 static void pc_compat_2_2(MachineState *machine)
 {
+    has_imutable_rsdp = true;
 }
 
 static void pc_compat_2_1(MachineState *machine)
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 121f620..6bbc100 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -50,6 +50,7 @@
 #define MAX_SATA_PORTS     6
 
 static bool has_acpi_build = true;
+static bool has_imutable_rsdp;
 static bool smbios_defaults = true;
 static bool smbios_legacy_mode;
 static bool smbios_uuid_encoded = true;
@@ -154,6 +155,7 @@ static void pc_q35_init(MachineState *machine)
     guest_info->isapc_ram_fw = false;
     guest_info->has_acpi_build = has_acpi_build;
     guest_info->has_reserved_memory = has_reserved_memory;
+    guest_info->has_imutable_rsdp = has_imutable_rsdp;
 
     /* Migration was not supported in 2.0 for Q35, so do not bother
      * with this hack (see hw/i386/acpi-build.c).
@@ -289,6 +291,7 @@ static void pc_q35_init(MachineState *machine)
 
 static void pc_compat_2_2(MachineState *machine)
 {
+    has_imutable_rsdp = true;
 }
 
 static void pc_compat_2_1(MachineState *machine)
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 69d9cf8..acc95ea 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -104,6 +104,7 @@ struct PcGuestInfo {
     int legacy_acpi_table_size;
     bool has_acpi_build;
     bool has_reserved_memory;
+    bool has_imutable_rsdp;
 };
 
 /* parallel.c */
-- 
1.8.3.1