xen/x86: Check supported features even for PVH dom0

The supported features ELF notes was tested only if the dom0 was
PV. Factor out a function to check ELF notes and reuse it even
for PVH.

Signed-off-by: Frediano Ziglio <frediano.ziglio@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 44429b6931
master date: 2026-04-09 21:04:58 +0100

xen/arch/x86/dom0_build.c

@@ -320,6 +320,18 @@ unsigned long __init dom0_paging_pages(const struct domain *d,
     return DIV_ROUND_UP(memkb, 1024) << (20 - PAGE_SHIFT);
 }
 
+int __init initdom_check_parms(
+    const struct domain *d, const struct elf_dom_parms *parms)
+{
+    if ( parms->elf_notes[XEN_ELFNOTE_SUPPORTED_FEATURES].type != XEN_ENT_NONE &&
+         is_hardware_domain(d) && !test_bit(XENFEAT_dom0, parms->f_supported) )
+    {
+        printk("Kernel does not support Dom0 operation\n");
+        return -EINVAL;
+    }
+
+    return 0;
+}
 
 /*
  * If allocation isn't specified, reserve 1/16th of available memory for

xen/arch/x86/hvm/dom0_build.c

@@ -692,6 +692,9 @@ static int __init pvh_load_kernel(
         return -EINVAL;
     }
 
+    if ( (rc = initdom_check_parms(d, &parms)) != 0 )
+        return rc;
+
     /* Copy the OS image and free temporary buffer. */
     elf.dest_base = (void *)(parms.virt_kstart - parms.virt_base);
     elf.dest_size = parms.virt_kend - parms.virt_kstart;

xen/arch/x86/include/asm/dom0_build.h

@@ -8,6 +8,8 @@
 
 extern unsigned int dom0_memflags;
 
+int initdom_check_parms(const struct domain *d,
+                        const struct elf_dom_parms *parms);
 unsigned long dom0_compute_nr_pages(struct domain *d,
                                     struct elf_dom_parms *parms,
                                     unsigned long initrd_len);

xen/arch/x86/pv/dom0_build.c

@@ -494,14 +494,8 @@ static int __init dom0_construct(const struct boot_domain *bd)
         return -EINVAL;
     }
 
-    if ( parms.elf_notes[XEN_ELFNOTE_SUPPORTED_FEATURES].type != XEN_ENT_NONE )
-    {
-        if ( !pv_shim && !test_bit(XENFEAT_dom0, parms.f_supported) )
-        {
-            printk("Kernel does not support Dom0 operation\n");
-            return -EINVAL;
-        }
-    }
+    if ( (rc = initdom_check_parms(d, &parms)) != 0 )
+        return rc;
 
     nr_pages = dom0_compute_nr_pages(d, &parms, initrd_len);