From d913f204e005893f2a9f853e8931b5f5a5a2f143 Mon Sep 17 00:00:00 2001
From: Michal Privoznik <mprivozn@redhat.com>
Date: Tue, 30 Jul 2024 17:36:39 +0200
Subject: [PATCH] qemu: Pre-create pstore device file

So far we are relying on QEMU or sysadmin to create the file for
pstore. This is suboptimal as in the case of the former we can
not set proper seclabels (there's nothing to set seclabels on
until QEMU is started).

Therefore, make sure the file is created before launching QEMU
and that it has the correct size.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
---
 src/qemu/qemu_process.c | 45 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 6255ba92e7..cec739c984 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -6835,6 +6835,48 @@ qemuProcessPrepareLaunchSecurityGuestInput(virDomainObj *vm)
 }
 
 
+static int
+qemuProcessPreparePstore(virDomainObj *vm)
+{
+    virDomainPstoreDef *pstore = vm->def->pstore;
+    VIR_AUTOCLOSE fd = -1;
+
+    if (!pstore)
+        return 0;
+
+    switch (pstore->backend) {
+    case VIR_DOMAIN_PSTORE_BACKEND_ACPI_ERST:
+        if ((fd = open(pstore->path, O_WRONLY | O_CREAT, 0600)) < 0) {
+            virReportSystemError(errno,
+                                 _("cannot create file '%1$s'"),
+                                 pstore->path);
+            return -1;
+        }
+
+        if (ftruncate(fd, pstore->size * 1024) < 0) {
+            virReportSystemError(errno,
+                                 _("Failed to truncate file '%1$s'"),
+                                 pstore->path);
+            return -1;
+        }
+
+        if (VIR_CLOSE(fd) < 0) {
+            virReportSystemError(errno,
+                                 _("Unable to save '%1$s'"),
+                                 pstore->path);
+            return -1;
+        }
+
+        break;
+
+    case VIR_DOMAIN_PSTORE_BACKEND_LAST:
+        break;
+    }
+
+    return 0;
+}
+
+
 static int
 qemuProcessPrepareHostStorageSourceVDPA(virStorageSource *src,
                                         qemuDomainObjPrivate *priv)
@@ -7333,6 +7375,9 @@ qemuProcessPrepareHost(virQEMUDriver *driver,
     if (qemuProcessPrepareLaunchSecurityGuestInput(vm) < 0)
         return -1;
 
+    if (qemuProcessPreparePstore(vm) < 0)
+        return -1;
+
     return 0;
 }