[SeaBIOS] [SeaBIOS PATCH 2/2] allow CPUs to have non-contiguous Local APIC IDs (v2)
Gleb Natapov
gleb at redhat.com
Mon Jul 23 14:20:14 CEST 2012
On Fri, Jul 20, 2012 at 02:04:50PM -0300, Eduardo Habkost wrote:
> Extract Local APIC IDs directly from the CPUs, and instead of check for
> "i < CountCPUs", check if the APIC ID was present on boot, when building
> ACPI tables and the MP-Table.
>
> This keeps ACPI Processor ID == APIC ID, but allows the
> hardware<->SeaBIOS interface be completely APIC-ID based and not depend
> on any other kind of "CPU identifier". This way, SeaBIOS may change the
> way ACPI Processor IDs are chosen in the future.
>
> As currently SeaBIOS supports only xAPIC and not x2APIC, the list of
> present-on-boot APIC IDs is a 256-bit bitmap. If one day SeaBIOS starts
> to support x2APIC, the data structure used to enumerate the APIC IDs
> will have to be changed (but this is an internal implementation detail,
> not visible to the OS or on any hardware<=>SeaBIOS interface).
>
> For current QEMU versions (that always make the APIC IDs contiguous),
> the OS-visible behavior and resulting ACPI tables should be exactly the
> same. This patch will simply allow QEMU to start setting non-contiguous
> APIC IDs (that is a requirement for some sockets/cores/threads topology
> settings).
>
> Changes v1 -> v2:
> - Use size suffixes on all asm instructions on smp.c
> - New patch description
>
> Signed-off-by: Eduardo Habkost <ehabkost at redhat.com>
> ---
> src/acpi-dsdt.dsl | 4 +++-
> src/acpi.c | 9 +++++----
> src/mptable.c | 2 +-
> src/smp.c | 17 +++++++++++++++++
> src/util.h | 1 +
> 5 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/src/acpi-dsdt.dsl b/src/acpi-dsdt.dsl
> index 2060686..72dc7d8 100644
> --- a/src/acpi-dsdt.dsl
> +++ b/src/acpi-dsdt.dsl
> @@ -676,6 +676,7 @@ DefinitionBlock (
> /* Methods called by run-time generated SSDT Processor objects */
> Method (CPMA, 1, NotSerialized) {
> // _MAT method - create an madt apic buffer
> + // Arg0 = Processor ID = Local APIC ID
> // Local0 = CPON flag for this cpu
> Store(DerefOf(Index(CPON, Arg0)), Local0)
> // Local1 = Buffer (in madt apic form) to return
> @@ -688,6 +689,7 @@ DefinitionBlock (
> }
> Method (CPST, 1, NotSerialized) {
> // _STA method - return ON status of cpu
> + // Arg0 = Processor ID = Local APIC ID
> // Local0 = CPON flag for this cpu
> Store(DerefOf(Index(CPON, Arg0)), Local0)
> If (Local0) { Return(0xF) } Else { Return(0x0) }
> @@ -708,7 +710,7 @@ DefinitionBlock (
> Store (PRS, Local5)
> // Local2 = last read byte from bitmap
> Store (Zero, Local2)
> - // Local0 = cpuid iterator
> + // Local0 = Processor ID / APIC ID iterator
> Store (Zero, Local0)
> While (LLess(Local0, SizeOf(CPON))) {
> // Local1 = CPON flag for this cpu
> diff --git a/src/acpi.c b/src/acpi.c
> index da3bc57..39b7172 100644
> --- a/src/acpi.c
> +++ b/src/acpi.c
> @@ -327,7 +327,7 @@ build_madt(void)
> apic->length = sizeof(*apic);
> apic->processor_id = i;
> apic->local_apic_id = i;
> - if (i < CountCPUs)
> + if (apic_id_is_present(apic->local_apic_id))
> apic->flags = cpu_to_le32(1);
> else
> apic->flags = cpu_to_le32(0);
> @@ -445,6 +445,7 @@ build_ssdt(void)
> }
>
> // build "Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}"
> + // Arg0 = Processor ID = APIC ID
> *(ssdt_ptr++) = 0x14; // MethodOp
> ssdt_ptr = encodeLen(ssdt_ptr, 2+5+(12*acpi_cpus), 2);
> *(ssdt_ptr++) = 'N';
> @@ -477,7 +478,7 @@ build_ssdt(void)
> ssdt_ptr = encodeLen(ssdt_ptr, 2+1+(1*acpi_cpus), 2);
> *(ssdt_ptr++) = acpi_cpus;
> for (i=0; i<acpi_cpus; i++)
> - *(ssdt_ptr++) = (i < CountCPUs) ? 0x01 : 0x00;
> + *(ssdt_ptr++) = (apic_id_is_present(i)) ? 0x01 : 0x00;
>
> // store pci io windows: start, end, length
> // this way we don't have to do the math in the dsdt
> @@ -656,10 +657,10 @@ build_srat(void)
> core->proximity_lo = curnode;
> memset(core->proximity_hi, 0, 3);
> core->local_sapic_eid = 0;
> - if (i < CountCPUs)
> + if (apic_id_is_present(i))
> core->flags = cpu_to_le32(1);
> else
> - core->flags = 0;
> + core->flags = cpu_to_le32(0);
> core++;
> }
>
> diff --git a/src/mptable.c b/src/mptable.c
> index 103f462..9406f98 100644
> --- a/src/mptable.c
> +++ b/src/mptable.c
> @@ -59,7 +59,7 @@ mptable_init(void)
> cpu->apicid = i;
> cpu->apicver = apic_version;
> /* cpu flags: enabled, bootstrap cpu */
> - cpu->cpuflag = ((i<CountCPUs) ? 0x01 : 0x00) | ((i==0) ? 0x02 : 0x00);
> + cpu->cpuflag = (apic_id_is_present(i) ? 0x01 : 0x00) | ((i==0) ? 0x02 : 0x00);
> cpu->cpusignature = cpuid_signature;
> cpu->featureflag = cpuid_features;
> cpu++;
> diff --git a/src/smp.c b/src/smp.c
> index 8c077a1..3c36f8c 100644
> --- a/src/smp.c
> +++ b/src/smp.c
> @@ -36,6 +36,8 @@ wrmsr_smp(u32 index, u64 val)
>
> u32 CountCPUs VAR16VISIBLE;
> u32 MaxCountCPUs VAR16VISIBLE;
> +// 256 bits for the found APIC IDs
> +u32 FoundAPICIDs[256/32] VAR16VISIBLE;
> extern void smp_ap_boot_code(void);
> ASM16(
> " .global smp_ap_boot_code\n"
> @@ -59,6 +61,12 @@ ASM16(
> " jmp 1b\n"
> "2:\n"
>
> + // get apic ID on EBX, set bit on FoundAPICIDs
> + " movl $1, %eax\n"
> + " cpuid\n"
> + " shrl $24, %ebx\n"
> + " lock btsl %ebx, FoundAPICIDs\n"
> +
> // Increment the cpu counter
> " lock incl CountCPUs\n"
You can get rid of CountCPUs by calculating FoundAPICIDs bitmap weight.
>
> @@ -67,6 +75,11 @@ ASM16(
> " jmp 1b\n"
> );
>
> +int apic_id_is_present(u8 apic_id)
> +{
> + return FoundAPICIDs[apic_id/32] & (1 << (apic_id % 32));
> +}
> +
> // find and initialize the CPUs by launching a SIPI to them
> void
> smp_probe(void)
> @@ -82,6 +95,10 @@ smp_probe(void)
> return;
> }
>
> + // mark the BSP initial APIC ID as found, too:
> + u8 apic_id = ebx>>24;
> + FoundAPICIDs[apic_id/32] |= (1 << (apic_id % 32));
> +
> // Init the counter.
> writel(&CountCPUs, 1);
>
> diff --git a/src/util.h b/src/util.h
> index ef8ec7c..89e928c 100644
> --- a/src/util.h
> +++ b/src/util.h
> @@ -355,6 +355,7 @@ extern u32 CountCPUs;
> extern u32 MaxCountCPUs;
> void wrmsr_smp(u32 index, u64 val);
> void smp_probe(void);
> +int apic_id_is_present(u8 apic_id);
>
> // coreboot.c
> extern const char *CBvendor, *CBpart;
> --
> 1.7.10.4
--
Gleb.
More information about the SeaBIOS
mailing list