On Tue, May 10, 2016 at 02:13:35PM +0200, Igor Mammedov wrote:
> On Mon, 9 May 2016 11:12:25 -0400
> "Kevin O'Connor" <ke...@koconnor.net> wrote:
>
> > On Mon, May 09, 2016 at 11:43:53AM +0200, Igor Mammedov wrote:
> > > MPTable doesn't support more than 254 CPUs and
> > > QEMU supplies an alternative MADT table which
> > > guest will use instead of it. So do not install
> > > MPTable if more than 254 CPUs are provided.
> > >
> > > Signed-off-by: Igor Mammedov <imamm...@redhat.com>
> > > ---
> > > src/fw/mptable.c | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/src/fw/mptable.c b/src/fw/mptable.c
> > > index 47385cc..aec26f8 100644
> > > --- a/src/fw/mptable.c
> > > +++ b/src/fw/mptable.c
> > > @@ -24,6 +24,10 @@ mptable_setup(void)
> > > if (! CONFIG_MPTABLE)
> > > return;
> > >
> > > + if (romfile_loadint("etc/max-cpus", 0) > 255) {
> > > + dprintf(1, "MPTable doesn't support more than 254 CPUs. Skip
> > > it.\n");
> > > + return;
> > > + }
> > > dprintf(3, "init MPTable\n");
> > >
> > > // Config structure in temp area.
> >
> > Thanks. I'd prefer to not make further modifications to fw/mptable.c
> > though. I think it would be better to do something like (totally
> > untested):
> >
> > --- a/src/fw/paravirt.c
> > +++ b/src/fw/paravirt.c
> > @@ -154,8 +154,14 @@ qemu_platform_setup(void)
> > smp_setup();
> >
> > // Create bios tables
> > - pirtable_setup();
> > - mptable_setup();
> > + if (romfile_find("etc/legacy-tables-loader")) {
> > + // QEMU may specify the PIR and mptable (or leave empty for no
> > tables)
> > + romfile_loader_execute("etc/legacy-tables-loader");
> > + } else {
> > + // Load the legacy internal tables
> > + pirtable_setup();
> > + mptable_setup();
> > + }
> > smbios_setup();
> >
> > if (CONFIG_FW_ROMFILE_LOAD) {
> >
> > And then QEMU can create an empty fw_cfg file to suppress both the
> > mptable and the pir table. (Or, it can populate it to specify exactly
> > what QEMU wants in those tables.)
> I don't think QEMU would ever want to provide legacy tables
> as Seabios creates them just fine for supported by them
> amount of CPUs. It's just that mptable_setup() is broken
> when there is more than 255 CPUs which leads to out of bound
> read/write accesses when dealing with APIC ID > 255.
>
> Considering QEMU not being interested in legacy tables,
> how about following:
>
>
> --- a/src/fw/paravirt.c
> +++ b/src/fw/paravirt.c
> @@ -154,8 +154,10 @@ qemu_platform_setup(void)
> smp_setup();
>
> // Create bios tables
> - pirtable_setup();
> - mptable_setup();
> + if (MaxCountCPUs <= 255) {
> + pirtable_setup();
> + mptable_setup();
> + }
> smbios_setup();
>
> if (CONFIG_FW_ROMFILE_LOAD) {
Okay. I think something like:
...
if (romfile_loadint("etc/create-legacy-tables", 1)) {
pirtable_setup();
mptable_setup();
}
...
would be better. But, I'm also okay with the above MaxCountCPUs
solution.
Thanks.
-Kevin
_______________________________________________
SeaBIOS mailing list
SeaBIOS@seabios.org
https://www.coreboot.org/mailman/listinfo/seabios
