make domain_create() return a proper error code

While triggered by the XSA-9 fix, this really is of more general use;
that fix just pointed out very sharply that the current situation
with all domain creation failures reported to user (tools) space as
-ENOMEM is very unfortunate (actively misleading users _and_ support
personnel).

Pull over the pointer <-> error code conversion infrastructure from
Linux, and use it in domain_create() and all it callers.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 7fffdc4a95..57f8bc1f4e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1,6 +1,7 @@
 #include <xen/config.h>
 #include <xen/init.h>
 #include <xen/lib.h>
+#include <xen/err.h>
 #include <xen/sched.h>
 #include <xen/sched-if.h>
 #include <xen/domain.h>
@@ -1319,7 +1320,7 @@ void __init __start_xen(unsigned long mbi_p)
 
     /* Create initial domain 0. */
     dom0 = domain_create(0, DOMCRF_s3_integrity, 0);
-    if ( (dom0 == NULL) || (alloc_dom0_vcpu0() == NULL) )
+    if ( IS_ERR(dom0) || (alloc_dom0_vcpu0() == NULL) )
         panic("Error creating domain 0\n");
 
     dom0->is_privileged = 1;