From c90fb5a828a68512095d80c190c0f491e385438e Mon Sep 17 00:00:00 2001
From: Jiri Denemark <jdenemar@redhat.com>
Date: Tue, 6 Aug 2019 13:53:11 +0200
Subject: [PATCH] qemu: Pass correct qemuCaps to virDomainDefPostParse

Since qemuDomainDefPostParse callback requires qemuCaps, we need to make
sure it gets the capabilities stored in the domain's private data if the
domain is running. Passing NULL may cause QEMU capabilities probing to
be triggered in case QEMU binary changed in the meantime. When this
happens while a running domain object is locked, QMP event delivered to
the domain before QEMU capabilities probing finishes will deadlock the
event loop.

This patch fixes all paths leading to virDomainDefPostParse.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_driver.c  | 17 ++++++++++-------
 src/qemu/qemu_process.c |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index f6e9c8672d..4da8b0e623 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8326,6 +8326,7 @@ static int
 qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
                              virDomainDeviceDefPtr dev,
                              virCapsPtr caps,
+                             virQEMUCapsPtr qemuCaps,
                              unsigned int parse_flags,
                              virDomainXMLOptionPtr xmlopt)
 {
@@ -8517,7 +8518,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
          return -1;
     }
 
-    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, NULL) < 0)
+    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, qemuCaps) < 0)
         return -1;
 
     return 0;
@@ -8528,6 +8529,7 @@ static int
 qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
                              virDomainDeviceDefPtr dev,
                              virCapsPtr caps,
+                             virQEMUCapsPtr qemuCaps,
                              unsigned int parse_flags,
                              virDomainXMLOptionPtr xmlopt)
 {
@@ -8709,7 +8711,7 @@ qemuDomainDetachDeviceConfig(virDomainDefPtr vmdef,
         return -1;
     }
 
-    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, NULL) < 0)
+    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, qemuCaps) < 0)
         return -1;
 
     return 0;
@@ -8719,6 +8721,7 @@ static int
 qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
                              virDomainDeviceDefPtr dev,
                              virCapsPtr caps,
+                             virQEMUCapsPtr qemuCaps,
                              unsigned int parse_flags,
                              virDomainXMLOptionPtr xmlopt)
 {
@@ -8814,7 +8817,7 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
         return -1;
     }
 
-    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, NULL) < 0)
+    if (virDomainDefPostParse(vmdef, caps, parse_flags, xmlopt, qemuCaps) < 0)
         return -1;
 
     return 0;
@@ -8866,7 +8869,7 @@ qemuDomainAttachDeviceLiveAndConfig(virDomainObjPtr vm,
                                          false) < 0)
             goto cleanup;
 
-        if (qemuDomainAttachDeviceConfig(vmdef, devConf, caps,
+        if (qemuDomainAttachDeviceConfig(vmdef, devConf, caps, priv->qemuCaps,
                                          parse_flags,
                                          driver->xmlopt) < 0)
             goto cleanup;
@@ -9031,7 +9034,7 @@ static int qemuDomainUpdateDeviceFlags(virDomainPtr dom,
 
         /* virDomainDefCompatibleDevice call is delayed until we know the
          * device we're going to update. */
-        if ((ret = qemuDomainUpdateDeviceConfig(vmdef, dev, caps,
+        if ((ret = qemuDomainUpdateDeviceConfig(vmdef, dev, caps, priv->qemuCaps,
                                                 parse_flags,
                                                 driver->xmlopt)) < 0)
             goto endjob;
@@ -9126,7 +9129,7 @@ qemuDomainDetachDeviceLiveAndConfig(virQEMUDriverPtr driver,
         if (!vmdef)
             goto cleanup;
 
-        if (qemuDomainDetachDeviceConfig(vmdef, dev, caps,
+        if (qemuDomainDetachDeviceConfig(vmdef, dev, caps, priv->qemuCaps,
                                          parse_flags,
                                          driver->xmlopt) < 0)
             goto cleanup;
@@ -9212,7 +9215,7 @@ qemuDomainDetachDeviceAliasLiveAndConfig(virQEMUDriverPtr driver,
         if (virDomainDefFindDevice(vmdef, alias, &dev, true) < 0)
             goto cleanup;
 
-        if (qemuDomainDetachDeviceConfig(vmdef, &dev, caps,
+        if (qemuDomainDetachDeviceConfig(vmdef, &dev, caps, priv->qemuCaps,
                                          parse_flags, driver->xmlopt) < 0)
             goto cleanup;
     }
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index ffe4338854..22ff4c42af 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -5615,7 +5615,7 @@ qemuProcessInit(virQEMUDriverPtr driver,
     if (vm->def->postParseFailed) {
         VIR_DEBUG("re-running the post parse callback");
 
-        if (virDomainDefPostParse(vm->def, caps, 0, driver->xmlopt, NULL) < 0)
+        if (virDomainDefPostParse(vm->def, caps, 0, driver->xmlopt, priv->qemuCaps) < 0)
             goto cleanup;
     }