linux/arch/x86/include/asm/irq_vectors.h
Vitaly Kuznetsov 93286261de x86/hyperv: Reenlightenment notifications support
Hyper-V supports Live Migration notification. This is supposed to be used
in conjunction with TSC emulation: when a VM is migrated to a host with
different TSC frequency for some short period the host emulates the
accesses to TSC and sends an interrupt to notify about the event. When the
guest is done updating everything it can disable TSC emulation and
everything will start working fast again.

These notifications weren't required until now as Hyper-V guests are not
supposed to use TSC as a clocksource: in Linux the TSC is even marked as
unstable on boot. Guests normally use 'tsc page' clocksource and host
updates its values on migrations automatically.

Things change when with nested virtualization: even when the PV
clocksources (kvm-clock or tsc page) are passed through to the nested
guests the TSC frequency and frequency changes need to be know..

Hyper-V Top Level Functional Specification (as of v5.0b) wrongly specifies
EAX:BIT(12) of CPUID:0x40000009 as the feature identification bit. The
right one to check is EAX:BIT(13) of CPUID:0x40000003. I was assured that
the fix in on the way.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: devel@linuxdriverproject.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Cathy Avery <cavery@redhat.com>
Cc: Mohammed Gamal <mmorsy@redhat.com>
Link: https://lkml.kernel.org/r/20180124132337.30138-4-vkuznets@redhat.com
2018-01-30 23:55:32 +01:00

153 lines
4.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_IRQ_VECTORS_H
#define _ASM_X86_IRQ_VECTORS_H
#include <linux/threads.h>
/*
* Linux IRQ vector layout.
*
* There are 256 IDT entries (per CPU - each entry is 8 bytes) which can
* be defined by Linux. They are used as a jump table by the CPU when a
* given vector is triggered - by a CPU-external, CPU-internal or
* software-triggered event.
*
* Linux sets the kernel code address each entry jumps to early during
* bootup, and never changes them. This is the general layout of the
* IDT entries:
*
* Vectors 0 ... 31 : system traps and exceptions - hardcoded events
* Vectors 32 ... 127 : device interrupts
* Vector 128 : legacy int80 syscall interface
* Vectors 129 ... INVALIDATE_TLB_VECTOR_START-1 except 204 : device interrupts
* Vectors INVALIDATE_TLB_VECTOR_START ... 255 : special interrupts
*
* 64-bit x86 has per CPU IDT tables, 32-bit has one shared IDT table.
*
* This file enumerates the exact layout of them:
*/
#define NMI_VECTOR 0x02
#define MCE_VECTOR 0x12
/*
* IDT vectors usable for external interrupt sources start at 0x20.
* (0x80 is the syscall vector, 0x30-0x3f are for ISA)
*/
#define FIRST_EXTERNAL_VECTOR 0x20
/*
* We start allocating at 0x21 to spread out vectors evenly between
* priority levels. (0x80 is the syscall vector)
*/
#define VECTOR_OFFSET_START 1
/*
* Reserve the lowest usable vector (and hence lowest priority) 0x20 for
* triggering cleanup after irq migration. 0x21-0x2f will still be used
* for device interrupts.
*/
#define IRQ_MOVE_CLEANUP_VECTOR FIRST_EXTERNAL_VECTOR
#define IA32_SYSCALL_VECTOR 0x80
/*
* Vectors 0x30-0x3f are used for ISA interrupts.
* round up to the next 16-vector boundary
*/
#define ISA_IRQ_VECTOR(irq) (((FIRST_EXTERNAL_VECTOR + 16) & ~15) + irq)
/*
* Special IRQ vectors used by the SMP architecture, 0xf0-0xff
*
* some of the following vectors are 'rare', they are merged
* into a single vector (CALL_FUNCTION_VECTOR) to save vector space.
* TLB, reschedule and local APIC vectors are performance-critical.
*/
#define SPURIOUS_APIC_VECTOR 0xff
/*
* Sanity check
*/
#if ((SPURIOUS_APIC_VECTOR & 0x0F) != 0x0F)
# error SPURIOUS_APIC_VECTOR definition error
#endif
#define ERROR_APIC_VECTOR 0xfe
#define RESCHEDULE_VECTOR 0xfd
#define CALL_FUNCTION_VECTOR 0xfc
#define CALL_FUNCTION_SINGLE_VECTOR 0xfb
#define THERMAL_APIC_VECTOR 0xfa
#define THRESHOLD_APIC_VECTOR 0xf9
#define REBOOT_VECTOR 0xf8
/*
* Generic system vector for platform specific use
*/
#define X86_PLATFORM_IPI_VECTOR 0xf7
/*
* IRQ work vector:
*/
#define IRQ_WORK_VECTOR 0xf6
#define UV_BAU_MESSAGE 0xf5
#define DEFERRED_ERROR_VECTOR 0xf4
/* Vector on which hypervisor callbacks will be delivered */
#define HYPERVISOR_CALLBACK_VECTOR 0xf3
/* Vector for KVM to deliver posted interrupt IPI */
#ifdef CONFIG_HAVE_KVM
#define POSTED_INTR_VECTOR 0xf2
#define POSTED_INTR_WAKEUP_VECTOR 0xf1
#define POSTED_INTR_NESTED_VECTOR 0xf0
#endif
#define MANAGED_IRQ_SHUTDOWN_VECTOR 0xef
#if IS_ENABLED(CONFIG_HYPERV)
#define HYPERV_REENLIGHTENMENT_VECTOR 0xee
#endif
#define LOCAL_TIMER_VECTOR 0xed
#define NR_VECTORS 256
#ifdef CONFIG_X86_LOCAL_APIC
#define FIRST_SYSTEM_VECTOR LOCAL_TIMER_VECTOR
#else
#define FIRST_SYSTEM_VECTOR NR_VECTORS
#endif
#define FPU_IRQ 13
/*
* Size the maximum number of interrupts.
*
* If the irq_desc[] array has a sparse layout, we can size things
* generously - it scales up linearly with the maximum number of CPUs,
* and the maximum number of IO-APICs, whichever is higher.
*
* In other cases we size more conservatively, to not create too large
* static arrays.
*/
#define NR_IRQS_LEGACY 16
#define CPU_VECTOR_LIMIT (64 * NR_CPUS)
#define IO_APIC_VECTOR_LIMIT (32 * MAX_IO_APICS)
#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_PCI_MSI)
#define NR_IRQS \
(CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ? \
(NR_VECTORS + CPU_VECTOR_LIMIT) : \
(NR_VECTORS + IO_APIC_VECTOR_LIMIT))
#elif defined(CONFIG_X86_IO_APIC)
#define NR_IRQS (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
#elif defined(CONFIG_PCI_MSI)
#define NR_IRQS (NR_VECTORS + CPU_VECTOR_LIMIT)
#else
#define NR_IRQS NR_IRQS_LEGACY
#endif
#endif /* _ASM_X86_IRQ_VECTORS_H */