On Wed, May 14, 2014 at 02:55:15PM +0100, Wei Liu wrote:
> On Wed, May 14, 2014 at 03:31:48PM +0200, Laszlo Ersek wrote:
> > On 05/14/14 00:13, Gabriel L. Somlo wrote:
> > > The SMBIOS specification requires some structure types to
> > > contain reference fields to other structures' handles. When
> > > InstallAllStructures() rebuilds the SMBIOS tables by traversing
> > > an existing source table, the use of SMBIOS_HANDLE_PI_RESERVED
> > > causes automatically generated, arbitrary handle numbers to be
> > > assigned to each cloned structure. This causes all reference
> > > handle fields to become invalid.
> > >
> > > This patch modifies InstallAllStructures() to reuse the original
> > > handle numbers supplied by the underlying VM, preserving the
> > > correctness of any included handle references.
> > >
> > > Contributed-under: TianoCore Contribution Agreement 1.0
> > > Signed-off-by: Gabriel Somlo <so...@cmu.edu>
> > > ---
> > > OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c
> > > b/OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c
> > > index 42a5132..ac48fb7 100644
> > > --- a/OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c
> > > +++ b/OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c
> > > @@ -106,7 +106,7 @@ InstallAllStructures (
> > > //
> > > // Log the SMBIOS data for this structure
> > > //
> > > - SmbiosHandle = SMBIOS_HANDLE_PI_RESERVED;
> > > + SmbiosHandle = SmbiosTable.Hdr->Handle;
> > > Status = Smbios->Add (
> > > Smbios,
> > > NULL,
> > >
> >
> > This patch should be tested by Xen people (I'm CC'ing Wei Liu). In
> > general it seems reasonable to me; it matches the smbios spec and the
> > qemu-side code.
> >
> > Reviewed-by: Laszlo Ersek <ler...@redhat.com>
>
> Thanks for the heads up. Anthony (CC'ed) is working on OVMF now and he's
> also a maintainer for QEMU in Xen, so he might have a better idea than I
> do. He gracefully offers help on testing this change. He shall let you
> know if there's any problem.
Here's a quick example of what I'm talking about:
Handle 0x1000, DMI type 16, 23 bytes
Physical Memory Array
Location: Other
Use: System Memory
Error Correction Type: Multi-bit ECC
Maximum Capacity: 2 GB
Error Information Handle: Not Provided
Number Of Devices: 1
...
Handle 0x1300, DMI type 19, 31 bytes
Memory Array Mapped Address
Starting Address: 0x00000000000
Ending Address: 0x0007FFFFFFF
Range Size: 2 GB
Physical Array Handle: 0x1000
Partition Width: 1
The second struct (type 19) has a "Physical Array Handle set to
0x1000, which points it at the first one (type 16). If we renumber
the structs and change the type16 handle without also editing the
contents of the Phys. Array Handle in type 19, we end up with a
"dangling reference"... Better to say it's the responsibility of
the underlying VM to cross-link the structures correctly, and just
use the original handle numbers as given.
Thanks a ton,
--Gabriel
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