lwn.git/arch/x86/kernel/apic/apic_common.c, branch docs-fixes

x86: Restrict KVM-induced symbol exports to KVM modules where obvious/possible

2025-11-12T23:29:38+00:00

Extend KVM's export macro framework to provide EXPORT_SYMBOL_FOR_KVM(), and use the helper macro to export symbols for KVM throughout x86 if and only if KVM will build one or more modules, and only for those modules. To avoid unnecessary exports when CONFIG_KVM=m but kvm.ko will not be built (because no vendor modules are selected), let arch code #define EXPORT_SYMBOL_FOR_KVM to suppress/override the exports. Note, the set of symbols to restrict to KVM was generated by manual search and audit; any "misses" are due to human error, not some grand plan. Signed-off-by: Sean Christopherson Signed-off-by: Dave Hansen Acked-by: Kai Huang Tested-by: Kai Huang Link: https://patch.msgid.link/20251112173944.1380633-5-seanjc%40google.com

x86/apic: Remove yet another dubious callback

2024-02-15T21:07:41+00:00

Paranoia is not wrong, but having an APIC callback which is in most implementations a complete NOOP and in one actually looking whether the APICID of an upcoming CPU has been registered. The same APICID which was used to bring the CPU out of wait for startup. That's paranoia for the paranoia sake. Remove the voodoo. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley Tested-by: Sohil Mehta Link: https://lore.kernel.org/r/20240212154640.116510935@linutronix.de

x86/mpparse: Remove the physid_t bitmap wrapper

2024-02-15T21:07:41+00:00

physid_t is a wrapper around bitmap. Just remove the onion layer and use bitmap functionality directly. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley Tested-by: Sohil Mehta Link: https://lore.kernel.org/r/20240212154639.994904510@linutronix.de

x86/apic: Use u32 for cpu_present_to_apicid()

2023-10-10T12:38:19+00:00

APIC IDs are used with random data types u16, u32, int, unsigned int, unsigned long. Make it all consistently use u32 because that reflects the hardware register width and fixup a few related usage sites for consistency sake. Signed-off-by: Thomas Gleixner Tested-by: Juergen Gross Tested-by: Sohil Mehta Tested-by: Michael Kelley Tested-by: Peter Zijlstra (Intel) Tested-by: Zhang Rui Reviewed-by: Arjan van de Ven Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20230814085113.054064391@linutronix.de

x86/apic: Use u32 for check_apicid_used()

2023-10-10T12:38:18+00:00

APIC IDs are used with random data types u16, u32, int, unsigned int, unsigned long. Make it all consistently use u32 because that reflects the hardware register width and move the default implementation to local.h as there are no users outside the apic directory. Signed-off-by: Thomas Gleixner Tested-by: Juergen Gross Tested-by: Sohil Mehta Tested-by: Michael Kelley Tested-by: Peter Zijlstra (Intel) Tested-by: Zhang Rui Reviewed-by: Arjan van de Ven Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20230814085112.981956102@linutronix.de

x86/apic: Sanitize APIC ID range validation

2023-08-09T18:58:32+00:00

Now that everything has apic::max_apic_id set and the eventual update for the x2APIC case is in place, switch the apic_id_valid() helper to use apic::max_apic_id and remove the apic::apic_id_valid() callback. [ dhansen: Fix subject typo ] Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest)

x86/apic: Mop up apic::apic_id_registered()

2023-08-09T18:58:27+00:00

Really not a hotpath and again no reason for having a gazillion of empty callbacks returning 1. Make it return bool and provide one shared implementation for the remaining users. Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest)

x86/apic: Nuke empty init_apic_ldr() callbacks

2023-08-09T18:58:25+00:00

apic::init_apic_ldr() is only invoked when the APIC is initialized. So there is really no point in having: - Default empty callbacks all over the place - Two implementations of the actual LDR init function where one is just unreadable gunk but does exactly the same as the other. Make the apic::init_apic_ldr() invocation conditional, remove the empty callbacks and consolidate the two implementation into one. Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest)

x86/apic: Remove check_phys_apicid_present()

2023-08-09T18:58:22+00:00

The only silly usage site is gone. Remove the gunk which was even outright wrong in the bigsmp_32 case which returned true unconditionally. Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest)

x86/apic: Remove pointless x86_bios_cpu_apicid

2023-08-09T18:58:17+00:00

It's a useless copy of x86_cpu_to_apicid. Signed-off-by: Thomas Gleixner Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Sohil Mehta Tested-by: Juergen Gross # Xen PV (dom0 and unpriv. guest)