virt: correctly detect QEMU emulated pSeries guests

Resolves: #26629
(cherry picked from commit 8c7a6c7)
(cherry picked from commit 1a22006)
(cherry picked from commit 48911dc)
(cherry picked from commit 0857956)

Author: mrc0mmand

src/basic/virt.c

@@ -98,6 +98,7 @@ static int detect_vm_device_tree(void) {
         r = read_one_line_file("/proc/device-tree/hypervisor/compatible", &hvtype);
         if (r == -ENOENT) {
                 _cleanup_closedir_ DIR *dir = NULL;
+                _cleanup_free_ char *compat = NULL;
 
                 if (access("/proc/device-tree/ibm,partition-name", F_OK) == 0 &&
                     access("/proc/device-tree/hmc-managed?", F_OK) == 0 &&
@@ -119,6 +120,14 @@ static int detect_vm_device_tree(void) {
                                 return VIRTUALIZATION_QEMU;
                         }
 
+                r = read_one_line_file("/proc/device-tree/compatible", &compat);
+                if (r < 0 && r != -ENOENT)
+                        return r;
+                if (r >= 0 && streq(compat, "qemu,pseries")) {
+                        log_debug("Virtualization %s found in /proc/device-tree/compatible", compat);
+                        return VIRTUALIZATION_QEMU;
+                }
+
                 log_debug("No virtualization found in /proc/device-tree/*");
                 return VIRTUALIZATION_NONE;
         } else if (r < 0)