From de355b7873e90c99c45945aa1fbe6d83c0fc7481 Mon Sep 17 00:00:00 2001
From: Michal Privoznik <mprivozn@redhat.com>
Date: Mon, 29 Jul 2024 09:43:35 +0200
Subject: [PATCH] qemu: Autofill pstore path if missing

Introduced only a couple of commits ago (in
v10.5.0-84-g90e50e67c6) the pstore device acts as a nonvolatile
storage, where guest kernel can store information about crashes.
This device, however, expects a file in the host from which the
crash data is read. So far, we expected users to provide a path,
but we can autogenerate one if missing. Just put it next to
per-domain's NVRAM stores.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
---
 docs/formatdomain.rst             |  3 +--
 src/conf/schemas/domaincommon.rng |  8 +++++---
 src/qemu/qemu_domain.c            | 27 ++++++++++++++++++++++++++-
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index 860ef17d7b..c56b739b23 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -8683,8 +8683,7 @@ desired backend (only ``acpi-erst`` is accepted for now). Then it has the
 following child elements:
 
 ``path``
-  Represents a path in the host that backs the pstore device in the guest. It
-  is mandatory.
+  Represents a path in the host that backs the pstore device in the guest.
 
 ``size``
   Configures the size of the persistent storage available to the guest. It is
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng
index 6fcee2a70c..7d58dce465 100644
--- a/src/conf/schemas/domaincommon.rng
+++ b/src/conf/schemas/domaincommon.rng
@@ -6261,9 +6261,11 @@
         <value>acpi-erst</value>
       </attribute>
       <interleave>
-        <element name="path">
-          <ref name="absFilePath"/>
-        </element>
+        <optional>
+          <element name="path">
+            <ref name="absFilePath"/>
+          </element>
+        </optional>
         <element name="size">
           <ref name="scaledInteger"/>
         </element>
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 298f4bfb9e..198ab99aef 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -6289,6 +6289,28 @@ qemuDomainMemoryDefPostParse(virDomainMemoryDef *mem, virArch arch,
 }
 
 
+static int
+qemuDomainPstoreDefPostParse(virDomainPstoreDef *pstore,
+                             const virDomainDef *def,
+                             virQEMUDriver *driver)
+{
+    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+
+    switch (pstore->backend) {
+    case VIR_DOMAIN_PSTORE_BACKEND_ACPI_ERST:
+        if (!pstore->path)
+            pstore->path = g_strdup_printf("%s/%s_PSTORE.raw",
+                                           cfg->nvramDir, def->name);
+        break;
+
+    case VIR_DOMAIN_PSTORE_BACKEND_LAST:
+        break;
+    }
+
+    return 0;
+}
+
+
 static int
 qemuDomainDeviceDefPostParse(virDomainDeviceDef *dev,
                              const virDomainDef *def,
@@ -6350,6 +6372,10 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDef *dev,
                                            parseFlags);
         break;
 
+    case VIR_DOMAIN_DEVICE_PSTORE:
+        ret = qemuDomainPstoreDefPostParse(dev->data.pstore, def, driver);
+        break;
+
     case VIR_DOMAIN_DEVICE_LEASE:
     case VIR_DOMAIN_DEVICE_FS:
     case VIR_DOMAIN_DEVICE_INPUT:
@@ -6365,7 +6391,6 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDef *dev,
     case VIR_DOMAIN_DEVICE_IOMMU:
     case VIR_DOMAIN_DEVICE_AUDIO:
     case VIR_DOMAIN_DEVICE_CRYPTO:
-    case VIR_DOMAIN_DEVICE_PSTORE:
         ret = 0;
         break;