On Tue, Jan 31, 2017 at 04:38:04PM +0000, Sironi, Filippo wrote:
On 27 Jan 2017, at 06:27, Kevin O'Connor kevin@koconnor.net wrote: On Fri, Jan 27, 2017 at 02:18:39AM +0100, Filippo Sironi wrote:
When running Linux on an Intel machine with a commodity BIOS, CPUs are numbered starting from 0 and the first half refers to the first logical CPU on each core while the second half refers to the second logical CPU on each core. As an example, on machine with 2 sockets, 4 cores per socket, and 2 logical CPUs per core, CPUs would be numbered:
- 0 1 2 3 - first logical CPU on each core of socket 0
- 4 5 6 7 - first logical CPU on each core of socket 1
- 8 9 10 11 - second logical CPU on each core of socket 0
- 12 13 14 15 - second logical CPU on each core of socket 1
With seabios (prior to this patch), CPU 0 would be the first logical CPU on core 0 of socket 0, CPU 1 would be the second logical CPU on core 0 of socket 0, and so on. This is due to the fact that processor_id and local_apic_id are assigned with the same value when building MADT.
Exhaust the most-significant 7 bits of the 8-bit APIC ID and then come back to the least-significant bit when assigning local_apic_id, since the least-significant bit identifies the second logical CPU on a core.
If HTT isn't available, keep the previous behavior.
Signed-off-by: Filippo Sironi sironi@amazon.de
src/fw/acpi.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/src/fw/acpi.c b/src/fw/acpi.c index 8bc2ca6..864c247 100644 --- a/src/fw/acpi.c +++ b/src/fw/acpi.c
The acpi.c code in seabios is deprecated. With all recent version of qemu/kvm the acpi tables are obtained from qemu. So, if there is a desired change to the tables then a patch should be made for qemu.
What if someone is using SeaBIOS but isn't using QEMU?
The fw/acpi.c code is only ever active on QEMU.
-Kevin