[Qemu-devel] [PATCH] bios: Fix multiple calls into smbios_load_external()

[Qemu-devel] [PATCH] bios: Fix multiple calls into smbios_load_external()

[Alex Williamson]

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>
--

diff --git a/bios/rombios32.c b/bios/rombios32.c
index f861f81..c869798 100644
--- a/bios/rombios32.c
+++ b/bios/rombios32.c
@@ -2554,13 +2554,14 @@ 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)

Re: [Qemu-devel] [PATCH] bios: Fix multiple calls into smbios_load_external()

[Markus Armbruster]

Alex Williamson <alex.williamson@hp.com> writes:

> 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>
> --

For what it's worth, I got bitten by this bug (one of two CPUs missing
from dmidecode), and the patch fixes it.