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From 2343d566f8dff6f97dfb280fbf409ff20379640c Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Date: Wed, 1 Aug 2018 12:55:19 +0000
Subject: [PATCH 14/21] migration: introduce decompress-error-check

RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: <20180801135522.11658-16-dgilbert@redhat.com>
Patchwork-id: 81575
O-Subject: [qemu-kvm RHEL8/virt212 PATCH 15/18] migration: introduce decompress-error-check
Bugzilla: 1594384
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>

From: Xiao Guangrong <xiaoguangrong@tencent.com>

QEMU 3.0 enables strict check for compression & decompression to
make the migration more robust, that depends on the source to fix
the internal design which triggers the unexpected error conditions

To make it work for migrating old version QEMU to 2.13 QEMU, we
introduce this parameter to disable the error check on the
destination which is the default behavior of the machine type
which is older than 2.13, alternately, the strict check can be
enabled explicitly as followings:
      -M pc-q35-2.11 -global migration.decompress-error-check=true

Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit f548222c24342ca74689de7794f9006b43f86a54)
  added compat entry to HW_COMPAT_RHEL7_5
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Context conflict in compat.h; 8.0 hasn't got the cirrus change 7.6 has
---
 hw/arm/virt.c         | 4 ++++
 hw/i386/pc_piix.c     | 1 +
 hw/i386/pc_q35.c      | 1 +
 include/hw/compat.h   | 5 +++++
 migration/migration.c | 4 ++++
 migration/migration.h | 8 ++++++++
 migration/ram.c       | 2 +-
 7 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index a4d0f52..751a93c 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1607,6 +1607,9 @@ static void machvirt_machine_init(void)
 }
 type_init(machvirt_machine_init);
 
+#define VIRT_COMPAT_2_12 \
+    HW_COMPAT_2_12
+
 static void virt_2_12_instance_init(Object *obj)
 {
     VirtMachineState *vms = VIRT_MACHINE(obj);
@@ -1669,6 +1672,7 @@ static void virt_2_12_instance_init(Object *obj)
 
 static void virt_machine_2_12_options(MachineClass *mc)
 {
+    SET_MACHINE_COMPAT(mc, VIRT_COMPAT_2_12);
 }
 DEFINE_VIRT_MACHINE_AS_LATEST(2, 12)
 
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 60441c1..9d9cee0 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -432,6 +432,7 @@ static void pc_i440fx_2_12_machine_options(MachineClass *m)
     pc_i440fx_machine_options(m);
     m->alias = "pc";
     m->is_default = 1;
+    SET_MACHINE_COMPAT(m, PC_COMPAT_2_12);
 }
 
 DEFINE_I440FX_MACHINE(v2_12, "pc-i440fx-2.12", NULL,
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index ccdeb11..90f12b1 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -313,6 +313,7 @@ static void pc_q35_2_12_machine_options(MachineClass *m)
 {
     pc_q35_machine_options(m);
     m->alias = "q35";
+    SET_MACHINE_COMPAT(m, PC_COMPAT_2_12);
 }
 
 DEFINE_Q35_MACHINE(v2_12, "pc-q35-2.12", NULL,
diff --git a/include/hw/compat.h b/include/hw/compat.h
index c343e8f..8b59c30 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -477,6 +477,11 @@
         .driver   = "cirrus-vga",\
         .property = "vgamem_mb",\
         .value    = "16",\
+    },{ /* HW_COMPAT_RHEL7_5 */ \
+        .driver   = "migration",\
+        .property = "decompress-error-check",\
+        .value    = "off",\
     },
 
+
 #endif /* HW_COMPAT_H */
diff --git a/migration/migration.c b/migration/migration.c
index 43d8a64..b6294f6 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2483,6 +2483,8 @@ void migration_global_dump(Monitor *mon)
                    ms->send_configuration ? "on" : "off");
     monitor_printf(mon, "send-section-footer: %s\n",
                    ms->send_section_footer ? "on" : "off");
+    monitor_printf(mon, "decompress-error-check: %s\n",
+                   ms->decompress_error_check ? "on" : "off");
 }
 
 #define DEFINE_PROP_MIG_CAP(name, x)             \
@@ -2496,6 +2498,8 @@ static Property migration_properties[] = {
                      send_configuration, true),
     DEFINE_PROP_BOOL("send-section-footer", MigrationState,
                      send_section_footer, true),
+    DEFINE_PROP_BOOL("decompress-error-check", MigrationState,
+                      decompress_error_check, true),
 
     /* Migration parameters */
     DEFINE_PROP_UINT8("x-compress-level", MigrationState,
diff --git a/migration/migration.h b/migration/migration.h
index 06833d7..a9c5c7f 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -182,6 +182,14 @@ struct MigrationState
     bool send_configuration;
     /* Whether we send section footer during migration */
     bool send_section_footer;
+
+    /*
+     * Whether we abort the migration if decompression errors are
+     * detected at the destination. It is left at false for qemu
+     * older than 3.0, since only newer qemu sends streams that
+     * do not trigger spurious decompression errors.
+     */
+    bool decompress_error_check;
 };
 
 void migrate_set_state(int *state, int old_state, int new_state);
diff --git a/migration/ram.c b/migration/ram.c
index c982201..bd563b5 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2582,7 +2582,7 @@ static void *do_data_decompress(void *opaque)
 
             ret = qemu_uncompress_data(&param->stream, des, pagesize,
                                        param->compbuf, len);
-            if (ret < 0) {
+            if (ret < 0 && migrate_get_current()->decompress_error_check) {
                 error_report("decompress data failed");
                 qemu_file_set_error(decomp_file, ret);
             }
-- 
1.8.3.1