bios: Fix missing DMI table entries

Upstream qemu-kvm commit 12766cd6 can make the BIOS to swallow DMI table
entries.  I observed it swallowing one of two CPUs by booting from
RHEL-3.8 installation media and running dmidecode.  With the patch
applied, dmidecode shows both CPUs again.

Patch snatched from qemu-devel, where it has been ignored so far (I
posted a nudge):

    From: Alex Williamson <alex.williamson@hp.com>
    Subject: [Qemu-devel] [PATCH RESEND] bios: Fix multiple calls into
            smbios_load_external()
    To: qemu-devel <qemu-devel@nongnu.org>
    Cc: Beth Kon <eak@us.ibm.com>
    Date: Mon, 15 Jun 2009 09:41:32 -0600
    Message-Id: <1243528568.25164.47.camel@bling>
    Organization: OSLO R&D

    We're marking the used entry bitmap in smbios_load_external() for each
    type we check, regardless of whether we loaded anything.  This makes
    subsequent calls behave as if we've already loaded the tables from qemu
    and can result in missing tables (ex. multiple type4 entries on an SMP
    guest).  Only mark the bitmap if we actually load something.

    Signed-off-by: Alex Williamson <alex.williamson@hp.com>

Bug 504713, please ACK.

Message-ID: <87skhy6efg.fsf@pike.pond.sub.org>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Bugzilla: 504713
RH-Upstream-status: submitted(qemu-devel)
Acked-by: Zachary Amsden <zamsden@redhat.com>
Acked-by: Avi Kivity <avi@redhat.com>
Acked-by: Gleb Natapov <gleb@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/bios/rombios32.c b/bios/rombios32.c
index b0494873..6c03eb3c 100755
--- a/bios/rombios32.c
+++ b/bios/rombios32.c
@@ -2276,13 +2276,14 @@ smbios_load_external(int type, char **p, unsigned *nr_structs,
             *max_struct_size = *p - (char *)header;
     }
 
-    /* Mark that we've reported on this type */
-    used_bitmap[(type >> 6) & 0x3] |= (1ULL << (type & 0x3f));
+    if (start != *p) {
+        /* Mark that we've reported on this type */
+        used_bitmap[(type >> 6) & 0x3] |= (1ULL << (type & 0x3f));
+        return 1;
+    }
 
-    return (start != *p);
-#else /* !BX_QEMU */
+#endif /* !BX_QEMU */
     return 0;
-#endif
 }
 
 void smbios_init(void)