Sorry for the delay. On Tue, Aug 17, 2021 at 8:41 PM Limonciello, Mario <mario.limonciello@xxxxxxx> wrote: > > On 8/16/2021 09:04, Rafael J. Wysocki wrote: > > On Fri, Aug 13, 2021 at 6:19 PM Mario Limonciello > > <mario.limonciello@xxxxxxx> wrote: > >> > >> A number of systems are showing "hotplug capable" CPUs when they > >> are not really hotpluggable. This is because the MADT has extra > >> CPU entries to support different CPUs that may be inserted into > >> the socket with different numbers of cores. > >> > >> Starting with ACPI 6.3 the spec has an Online Capable bit in the > >> MADT used to determine whether or not a CPU is hotplug capable > >> when the enabled bit is not set. > >> > >> Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fuefi.org%2Fhtmlspecs%2FACPI_Spec_6_4_html%2F05_ACPI_Software_Programming_Model%2FACPI_Software_Programming_Model.html%3F%23local-apic-flags&data=04%7C01%7Cmario.limonciello%40amd.com%7Ce6a384bf25274f88b49508d960bee40a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637647195281368169%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=3MWJ5NcRVJ7TP4tJH6uQRbqfZKSqe5RHjGxGbQEP13E%3D&reserved=0 > >> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > >> --- > >> arch/x86/kernel/acpi/boot.c | 10 ++++++++++ > >> include/acpi/actbl2.h | 1 + > >> 2 files changed, 11 insertions(+) > >> > >> Changes from v1->v2: > >> * Check the revision field in MADT to determine if it matches the > >> bump from ACPI 6.3 as suggested by Hanjun Guo > >> * Update description > >> > >> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > >> index e55e0c1fad8c..bfa69a5c9c0b 100644 > >> --- a/arch/x86/kernel/acpi/boot.c > >> +++ b/arch/x86/kernel/acpi/boot.c > >> @@ -53,6 +53,8 @@ int acpi_ioapic; > >> int acpi_strict; > >> int acpi_disable_cmcff; > >> > >> +bool acpi_support_online_capable; > > > > Missing static? > > Ack, thanks. > > > > >> + > >> /* ACPI SCI override configuration */ > >> u8 acpi_sci_flags __initdata; > >> u32 acpi_sci_override_gsi __initdata = INVALID_ACPI_IRQ; > >> @@ -138,6 +140,8 @@ static int __init acpi_parse_madt(struct acpi_table_header *table) > >> > >> pr_debug("Local APIC address 0x%08x\n", madt->address); > >> } > >> + if (madt->header.revision >= 5) > >> + acpi_support_online_capable = true; > >> > >> default_acpi_madt_oem_check(madt->header.oem_id, > >> madt->header.oem_table_id); > >> @@ -239,6 +243,12 @@ acpi_parse_lapic(union acpi_subtable_headers * header, const unsigned long end) > >> if (processor->id == 0xff) > >> return 0; > >> > >> + /* don't register processors that can not be onlined */ > >> + if (acpi_support_online_capable && > >> + !(processor->lapic_flags & ACPI_MADT_ENABLED) && > >> + !(processor->lapic_flags & ACPI_MADT_ONLINE_CAPABLE)) > >> + return 0; > >> + > >> /* > >> * We need to register disabled CPU as well to permit > >> * counting disabled CPUs. This allows us to size > >> diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h > >> index 2069ac38a4e2..fae45e383987 100644 > >> --- a/include/acpi/actbl2.h > >> +++ b/include/acpi/actbl2.h > > > > The one below is an ACPICA change and I'd prefer it to be integrated > > via the upstream ACPICA. > > > > Could you prepare an ACPICA pull request for just the bit below and > > send it via GitHub? > > Sure thing. > http://github.com/acpica/acpica/pull/708/ > > They said they would take it later this month or next month. > > Given that, how do you want to proceed with the first part of this? > > Should I send a 2 patch series that will add the MADT bit to actbl2.h in > advance of their next release, or should I wait to resubmit until after > their next release and you've brought it into your tree? If you want this to go into 5.15, I would suggest going for the first option. Knowing that the ACPICA patch is going to reach upstream at one point, I can put it into Linux in advance. > > > >> @@ -808,6 +808,7 @@ struct acpi_madt_multiproc_wakeup_mailbox { > >> /* MADT Local APIC flags */ > >> > >> #define ACPI_MADT_ENABLED (1) /* 00: Processor is usable if set */ > >> +#define ACPI_MADT_ONLINE_CAPABLE (2) /* 01: System HW supports enabling processor at runtime */ > >> > >> /* MADT MPS INTI flags (inti_flags) */ > >> > >> -- >
