[hyperv] Add support for Hyper-V hypervisor

Add support for detecting and communicating with the Hyper-V
hypervisor.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2014-12-11 17:22:18 +00:00
parent 1d2b7c91f7
commit d77a546fb4
10 changed files with 977 additions and 3 deletions

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@@ -9,6 +9,7 @@ SRCDIRS += arch/x86/interface/efi
SRCDIRS += arch/x86/prefix
SRCDIRS += arch/x86/hci/commands
SRCDIRS += arch/x86/drivers/xen
SRCDIRS += arch/x86/drivers/hyperv
# breaks building some of the linux-related objects
CFLAGS += -Ulinux

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@@ -0,0 +1,67 @@
/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/io.h>
#include <pic8259.h>
/** @file
*
* Minimal support for the 8259 Programmable Interrupt Controller
*
*/
/**
* Send non-specific EOI(s)
*
* @v irq IRQ number
*
* This seems to be inherently unsafe.
*/
static inline void send_nonspecific_eoi ( unsigned int irq ) {
DBG ( "Sending non-specific EOI for IRQ %d\n", irq );
if ( irq >= IRQ_PIC_CUTOFF ) {
outb ( ICR_EOI_NON_SPECIFIC, PIC2_ICR );
}
outb ( ICR_EOI_NON_SPECIFIC, PIC1_ICR );
}
/**
* Send specific EOI(s)
*
* @v irq IRQ number
*/
static inline void send_specific_eoi ( unsigned int irq ) {
DBG ( "Sending specific EOI for IRQ %d\n", irq );
if ( irq >= IRQ_PIC_CUTOFF ) {
outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( CHAINED_IRQ ) ),
ICR_REG ( CHAINED_IRQ ) );
}
outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( irq ) ), ICR_REG ( irq ) );
}
/**
* Send End-Of-Interrupt to the PIC
*
* @v irq IRQ number
*/
void send_eoi ( unsigned int irq ) {
send_specific_eoi ( irq );
}

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@@ -0,0 +1,553 @@
/*
* Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
/** @file
*
* Hyper-V driver
*
*/
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <byteswap.h>
#include <pic8259.h>
#include <ipxe/malloc.h>
#include <ipxe/device.h>
#include <ipxe/cpuid.h>
#include <ipxe/msr.h>
#include <ipxe/hyperv.h>
#include "hyperv.h"
/** Maximum time to wait for a message response
*
* This is a policy decision.
*/
#define HV_MESSAGE_MAX_WAIT_MS 1000
/**
* Convert a Hyper-V status code to an iPXE status code
*
* @v status Hyper-V status code
* @ret rc iPXE status code (before negation)
*/
#define EHV( status ) EPLATFORM ( EINFO_EPLATFORM, (status) )
/**
* Allocate zeroed pages
*
* @v hv Hyper-V hypervisor
* @v ... Page addresses to fill in, terminated by NULL
* @ret rc Return status code
*/
__attribute__ (( sentinel )) int
hv_alloc_pages ( struct hv_hypervisor *hv, ... ) {
va_list args;
void **page;
int i;
/* Allocate and zero pages */
va_start ( args, hv );
for ( i = 0 ; ( ( page = va_arg ( args, void ** ) ) != NULL ); i++ ) {
*page = malloc_dma ( PAGE_SIZE, PAGE_SIZE );
if ( ! *page )
goto err_alloc;
memset ( *page, 0, PAGE_SIZE );
}
va_end ( args );
return 0;
err_alloc:
va_end ( args );
va_start ( args, hv );
for ( ; i >= 0 ; i-- ) {
page = va_arg ( args, void ** );
free_dma ( *page, PAGE_SIZE );
}
va_end ( args );
return -ENOMEM;
}
/**
* Free pages
*
* @v hv Hyper-V hypervisor
* @v ... Page addresses, terminated by NULL
*/
__attribute__ (( sentinel )) void
hv_free_pages ( struct hv_hypervisor *hv, ... ) {
va_list args;
void *page;
va_start ( args, hv );
while ( ( page = va_arg ( args, void * ) ) != NULL )
free_dma ( page, PAGE_SIZE );
va_end ( args );
}
/**
* Allocate message buffer
*
* @v hv Hyper-V hypervisor
* @ret rc Return status code
*/
static int hv_alloc_message ( struct hv_hypervisor *hv ) {
/* Allocate buffer. Must be aligned to at least 8 bytes and
* must not cross a page boundary, so align on its own size.
*/
hv->message = malloc_dma ( sizeof ( *hv->message ),
sizeof ( *hv->message ) );
if ( ! hv->message )
return -ENOMEM;
return 0;
}
/**
* Free message buffer
*
* @v hv Hyper-V hypervisor
*/
static void hv_free_message ( struct hv_hypervisor *hv ) {
/* Free buffer */
free_dma ( hv->message, sizeof ( *hv->message ) );
}
/**
* Check whether or not we are running in Hyper-V
*
* @v hv Hyper-V hypervisor
* @ret rc Return status code
*/
static int hv_check_hv ( struct hv_hypervisor *hv ) {
struct x86_features features;
uint32_t interface_id;
uint32_t discard_ebx;
uint32_t discard_ecx;
uint32_t discard_edx;
/* Check for presence of a hypervisor (not necessarily Hyper-V) */
x86_features ( &features );
if ( ! ( features.intel.ecx & CPUID_FEATURES_INTEL_ECX_HYPERVISOR ) ) {
DBGC ( hv, "HV %p not running in a hypervisor\n", hv );
return -ENODEV;
}
/* Check that hypervisor is Hyper-V */
cpuid ( HV_CPUID_INTERFACE_ID, &interface_id, &discard_ebx,
&discard_ecx, &discard_edx );
if ( interface_id != HV_INTERFACE_ID ) {
DBGC ( hv, "HV %p not running in Hyper-V (interface ID "
"%#08x)\n", hv, interface_id );
return -ENODEV;
}
return 0;
}
/**
* Map hypercall page
*
* @v hv Hyper-V hypervisor
* @ret rc Return status code
*/
static int hv_map_hypercall ( struct hv_hypervisor *hv ) {
union {
struct {
uint32_t ebx;
uint32_t ecx;
uint32_t edx;
} __attribute__ (( packed ));
char text[ 13 /* "bbbbccccdddd" + NUL */ ];
} vendor_id;
uint32_t build;
uint32_t version;
uint32_t discard_eax;
uint32_t discard_ecx;
uint32_t discard_edx;
uint64_t guest_os_id;
uint64_t hypercall;
/* Report guest OS identity */
guest_os_id = rdmsr ( HV_X64_MSR_GUEST_OS_ID );
if ( guest_os_id != 0 ) {
DBGC ( hv, "HV %p guest OS ID MSR already set to %#08llx\n",
hv, guest_os_id );
return -EBUSY;
}
guest_os_id = HV_GUEST_OS_ID_IPXE;
DBGC2 ( hv, "HV %p guest OS ID MSR is %#08llx\n", hv, guest_os_id );
wrmsr ( HV_X64_MSR_GUEST_OS_ID, guest_os_id );
/* Get hypervisor system identity (for debugging) */
cpuid ( HV_CPUID_VENDOR_ID, &discard_eax, &vendor_id.ebx,
&vendor_id.ecx, &vendor_id.edx );
vendor_id.text[ sizeof ( vendor_id.text ) - 1 ] = '\0';
cpuid ( HV_CPUID_HYPERVISOR_ID, &build, &version, &discard_ecx,
&discard_edx );
DBGC ( hv, "HV %p detected \"%s\" version %d.%d build %d\n", hv,
vendor_id.text, ( version >> 16 ), ( version & 0xffff ), build );
/* Map hypercall page */
hypercall = rdmsr ( HV_X64_MSR_HYPERCALL );
hypercall &= ( PAGE_SIZE - 1 );
hypercall |= ( virt_to_phys ( hv->hypercall ) | HV_HYPERCALL_ENABLE );
DBGC2 ( hv, "HV %p hypercall MSR is %#08llx\n", hv, hypercall );
wrmsr ( HV_X64_MSR_HYPERCALL, hypercall );
return 0;
}
/**
* Unmap hypercall page
*
* @v hv Hyper-V hypervisor
*/
static void hv_unmap_hypercall ( struct hv_hypervisor *hv ) {
uint64_t hypercall;
uint64_t guest_os_id;
/* Unmap the hypercall page */
hypercall = rdmsr ( HV_X64_MSR_HYPERCALL );
hypercall &= ( ( PAGE_SIZE - 1 ) & ~HV_HYPERCALL_ENABLE );
DBGC2 ( hv, "HV %p hypercall MSR is %#08llx\n", hv, hypercall );
wrmsr ( HV_X64_MSR_HYPERCALL, hypercall );
/* Reset the guest OS identity */
guest_os_id = 0;
DBGC2 ( hv, "HV %p guest OS ID MSR is %#08llx\n", hv, guest_os_id );
wrmsr ( HV_X64_MSR_GUEST_OS_ID, guest_os_id );
}
/**
* Map synthetic interrupt controller
*
* @v hv Hyper-V hypervisor
* @ret rc Return status code
*/
static int hv_map_synic ( struct hv_hypervisor *hv ) {
uint64_t simp;
uint64_t siefp;
uint64_t scontrol;
/* Map SynIC message page */
simp = rdmsr ( HV_X64_MSR_SIMP );
simp &= ( PAGE_SIZE - 1 );
simp |= ( virt_to_phys ( hv->synic.message ) | HV_SIMP_ENABLE );
DBGC2 ( hv, "HV %p SIMP MSR is %#08llx\n", hv, simp );
wrmsr ( HV_X64_MSR_SIMP, simp );
/* Map SynIC event page */
siefp = rdmsr ( HV_X64_MSR_SIEFP );
siefp &= ( PAGE_SIZE - 1 );
siefp |= ( virt_to_phys ( hv->synic.event ) | HV_SIEFP_ENABLE );
DBGC2 ( hv, "HV %p SIEFP MSR is %#08llx\n", hv, siefp );
wrmsr ( HV_X64_MSR_SIEFP, siefp );
/* Enable SynIC */
scontrol = rdmsr ( HV_X64_MSR_SCONTROL );
scontrol |= HV_SCONTROL_ENABLE;
DBGC2 ( hv, "HV %p SCONTROL MSR is %#08llx\n", hv, scontrol );
wrmsr ( HV_X64_MSR_SCONTROL, scontrol );
return 0;
}
/**
* Unmap synthetic interrupt controller
*
* @v hv Hyper-V hypervisor
*/
static void hv_unmap_synic ( struct hv_hypervisor *hv ) {
uint64_t scontrol;
uint64_t siefp;
uint64_t simp;
/* Disable SynIC */
scontrol = rdmsr ( HV_X64_MSR_SCONTROL );
scontrol &= ~HV_SCONTROL_ENABLE;
DBGC2 ( hv, "HV %p SCONTROL MSR is %#08llx\n", hv, scontrol );
wrmsr ( HV_X64_MSR_SCONTROL, scontrol );
/* Unmap SynIC event page */
siefp = rdmsr ( HV_X64_MSR_SIEFP );
siefp &= ( ( PAGE_SIZE - 1 ) & ~HV_SIEFP_ENABLE );
DBGC2 ( hv, "HV %p SIEFP MSR is %#08llx\n", hv, siefp );
wrmsr ( HV_X64_MSR_SIEFP, siefp );
/* Unmap SynIC message page */
simp = rdmsr ( HV_X64_MSR_SIMP );
simp &= ( ( PAGE_SIZE - 1 ) & ~HV_SIMP_ENABLE );
DBGC2 ( hv, "HV %p SIMP MSR is %#08llx\n", hv, simp );
wrmsr ( HV_X64_MSR_SIMP, simp );
}
/**
* Enable synthetic interrupt
*
* @v hv Hyper-V hypervisor
* @v sintx Synthetic interrupt number
*/
void hv_enable_sint ( struct hv_hypervisor *hv, unsigned int sintx ) {
unsigned long msr = HV_X64_MSR_SINT ( sintx );
uint64_t sint;
/* Enable synthetic interrupt
*
* We have to enable the interrupt, otherwise messages will
* not be delivered (even though the documentation implies
* that polling for messages is possible). We enable AutoEOI
* and hook the interrupt to the obsolete IRQ13 (FPU
* exception) vector, which will be implemented as a no-op.
*/
sint = rdmsr ( msr );
sint &= ~( HV_SINT_MASKED | HV_SINT_VECTOR_MASK );
sint |= ( HV_SINT_AUTO_EOI |
HV_SINT_VECTOR ( IRQ_INT ( 13 /* See comment above */ ) ) );
DBGC2 ( hv, "HV %p SINT%d MSR is %#08llx\n", hv, sintx, sint );
wrmsr ( msr, sint );
}
/**
* Disable synthetic interrupt
*
* @v hv Hyper-V hypervisor
* @v sintx Synthetic interrupt number
*/
void hv_disable_sint ( struct hv_hypervisor *hv, unsigned int sintx ) {
unsigned long msr = HV_X64_MSR_SINT ( sintx );
uint64_t sint;
/* Disable synthetic interrupt */
sint = rdmsr ( msr );
sint &= ~HV_SINT_AUTO_EOI;
sint |= HV_SINT_MASKED;
DBGC2 ( hv, "HV %p SINT%d MSR is %#08llx\n", hv, sintx, sint );
wrmsr ( msr, sint );
}
/**
* Post message
*
* @v hv Hyper-V hypervisor
* @v id Connection ID
* @v type Message type
* @v data Message
* @v len Length of message
* @ret rc Return status code
*/
int hv_post_message ( struct hv_hypervisor *hv, unsigned int id,
unsigned int type, const void *data, size_t len ) {
struct hv_post_message *msg = &hv->message->posted;
int status;
int rc;
/* Sanity check */
assert ( len <= sizeof ( msg->data ) );
/* Construct message */
memset ( msg, 0, sizeof ( *msg ) );
msg->id = cpu_to_le32 ( id );
msg->type = cpu_to_le32 ( type );
msg->len = cpu_to_le32 ( len );
memcpy ( msg->data, data, len );
DBGC2 ( hv, "HV %p connection %d posting message type %#08x:\n",
hv, id, type );
DBGC2_HDA ( hv, 0, msg->data, len );
/* Post message */
if ( ( status = hv_call ( hv, HV_POST_MESSAGE, msg, NULL ) ) != 0 ) {
rc = -EHV ( status );
DBGC ( hv, "HV %p could not post message to %#08x: %s\n",
hv, id, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Wait for received message
*
* @v hv Hyper-V hypervisor
* @v sintx Synthetic interrupt number
* @ret rc Return status code
*/
int hv_wait_for_message ( struct hv_hypervisor *hv, unsigned int sintx ) {
struct hv_message *msg = &hv->message->received;
struct hv_message *src = &hv->synic.message[sintx];
unsigned int retries;
size_t len;
/* Wait for message to arrive */
for ( retries = 0 ; retries < HV_MESSAGE_MAX_WAIT_MS ; retries++ ) {
/* Check for message */
if ( src->type ) {
/* Copy message */
memset ( msg, 0, sizeof ( *msg ) );
len = src->len;
assert ( len <= sizeof ( *msg ) );
memcpy ( msg, src,
( offsetof ( typeof ( *msg ), data ) + len ) );
DBGC2 ( hv, "HV %p SINT%d received message type "
"%#08x:\n", hv, sintx,
le32_to_cpu ( msg->type ) );
DBGC2_HDA ( hv, 0, msg->data, len );
/* Consume message */
src->type = 0;
return 0;
}
/* Trigger message delivery */
wrmsr ( HV_X64_MSR_EOM, 0 );
/* Delay */
mdelay ( 1 );
}
DBGC ( hv, "HV %p SINT%d timed out waiting for message\n",
hv, sintx );
return -ETIMEDOUT;
}
/**
* Signal event
*
* @v hv Hyper-V hypervisor
* @v id Connection ID
* @v flag Flag number
* @ret rc Return status code
*/
int hv_signal_event ( struct hv_hypervisor *hv, unsigned int id,
unsigned int flag ) {
struct hv_signal_event *event = &hv->message->signalled;
int status;
int rc;
/* Construct event */
memset ( event, 0, sizeof ( *event ) );
event->id = cpu_to_le32 ( id );
event->flag = cpu_to_le16 ( flag );
/* Signal event */
if ( ( status = hv_call ( hv, HV_SIGNAL_EVENT, event, NULL ) ) != 0 ) {
rc = -EHV ( status );
DBGC ( hv, "HV %p could not signal event to %#08x: %s\n",
hv, id, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Probe root device
*
* @v rootdev Root device
* @ret rc Return status code
*/
static int hv_probe ( struct root_device *rootdev ) {
struct hv_hypervisor *hv;
int rc;
/* Allocate and initialise structure */
hv = zalloc ( sizeof ( *hv ) );
if ( ! hv ) {
rc = -ENOMEM;
goto err_alloc;
}
/* Check we are running in Hyper-V */
if ( ( rc = hv_check_hv ( hv ) ) != 0 )
goto err_check_hv;
/* Allocate pages */
if ( ( rc = hv_alloc_pages ( hv, &hv->hypercall, &hv->synic.message,
&hv->synic.event, NULL ) ) != 0 )
goto err_alloc_pages;
/* Allocate message buffer */
if ( ( rc = hv_alloc_message ( hv ) ) != 0 )
goto err_alloc_message;
/* Map hypercall page */
if ( ( rc = hv_map_hypercall ( hv ) ) != 0 )
goto err_map_hypercall;
/* Map synthetic interrupt controller */
if ( ( rc = hv_map_synic ( hv ) ) != 0 )
goto err_map_synic;
rootdev_set_drvdata ( rootdev, hv );
return 0;
hv_unmap_synic ( hv );
err_map_synic:
hv_unmap_hypercall ( hv );
err_map_hypercall:
hv_free_message ( hv );
err_alloc_message:
hv_free_pages ( hv, hv->hypercall, hv->synic.message, hv->synic.event,
NULL );
err_alloc_pages:
err_check_hv:
free ( hv );
err_alloc:
return rc;
}
/**
* Remove root device
*
* @v rootdev Root device
*/
static void hv_remove ( struct root_device *rootdev ) {
struct hv_hypervisor *hv = rootdev_get_drvdata ( rootdev );
hv_unmap_synic ( hv );
hv_unmap_hypercall ( hv );
hv_free_message ( hv );
hv_free_pages ( hv, hv->hypercall, hv->synic.message, hv->synic.event,
NULL );
free ( hv );
}
/** Hyper-V root device driver */
static struct root_driver hv_root_driver = {
.probe = hv_probe,
.remove = hv_remove,
};
/** Hyper-V root device */
struct root_device hv_root_device __root_device = {
.dev = { .name = "Hyper-V" },
.driver = &hv_root_driver,
};

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@@ -0,0 +1,42 @@
#ifndef _HYPERV_H
#define _HYPERV_H
/** @file
*
* Hyper-V driver
*
*/
FILE_LICENCE ( GPL2_OR_LATER );
/** Get vendor identification */
#define HV_CPUID_VENDOR_ID 0x40000000UL
/** Get interface identification */
#define HV_CPUID_INTERFACE_ID 0x40000001UL
/** Get hypervisor identification */
#define HV_CPUID_HYPERVISOR_ID 0x40000002UL
/** Guest OS identity MSR */
#define HV_X64_MSR_GUEST_OS_ID 0x40000000UL
/** Hypercall page MSR */
#define HV_X64_MSR_HYPERCALL 0x40000001UL
/** SynIC control MSR */
#define HV_X64_MSR_SCONTROL 0x40000080UL
/** SynIC event flags page MSR */
#define HV_X64_MSR_SIEFP 0x40000082UL
/** SynIC message page MSR */
#define HV_X64_MSR_SIMP 0x40000083UL
/** SynIC end of message MSR */
#define HV_X64_MSR_EOM 0x40000084UL
/** SynIC interrupt source MSRs */
#define HV_X64_MSR_SINT(x) ( 0x40000090UL + (x) )
#endif /* _HYPERV_H */

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@@ -46,6 +46,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
#define ERRFILE_timer_rdtsc ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00000000 )
#define ERRFILE_timer_bios ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00010000 )
#define ERRFILE_hvm ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00020000 )
#define ERRFILE_hyperv ( ERRFILE_ARCH | ERRFILE_DRIVER | 0x00030000 )
#define ERRFILE_cpuid_cmd ( ERRFILE_ARCH | ERRFILE_OTHER | 0x00000000 )
#define ERRFILE_cpuid_settings ( ERRFILE_ARCH | ERRFILE_OTHER | 0x00010000 )

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@@ -39,6 +39,9 @@ struct x86_features {
/** Get standard features */
#define CPUID_FEATURES 0x00000001UL
/** Hypervisor is present */
#define CPUID_FEATURES_INTEL_ECX_HYPERVISOR 0x80000000UL
/** Get largest extended function */
#define CPUID_AMD_MAX_FN 0x80000000UL

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@@ -0,0 +1,70 @@
/*
* Basic support for controlling the 8259 Programmable Interrupt Controllers.
*
* Initially written by Michael Brown (mcb30).
*/
FILE_LICENCE ( GPL2_OR_LATER );
#ifndef PIC8259_H
#define PIC8259_H
#include <ipxe/io.h>
#define IRQ_PIC_CUTOFF 8
/* 8259 register locations */
#define PIC1_ICW1 0x20
#define PIC1_OCW2 0x20
#define PIC1_OCW3 0x20
#define PIC1_ICR 0x20
#define PIC1_IRR 0x20
#define PIC1_ISR 0x20
#define PIC1_ICW2 0x21
#define PIC1_ICW3 0x21
#define PIC1_ICW4 0x21
#define PIC1_IMR 0x21
#define PIC2_ICW1 0xa0
#define PIC2_OCW2 0xa0
#define PIC2_OCW3 0xa0
#define PIC2_ICR 0xa0
#define PIC2_IRR 0xa0
#define PIC2_ISR 0xa0
#define PIC2_ICW2 0xa1
#define PIC2_ICW3 0xa1
#define PIC2_ICW4 0xa1
#define PIC2_IMR 0xa1
/* Register command values */
#define OCW3_ID 0x08
#define OCW3_READ_IRR 0x03
#define OCW3_READ_ISR 0x02
#define ICR_EOI_NON_SPECIFIC 0x20
#define ICR_EOI_NOP 0x40
#define ICR_EOI_SPECIFIC 0x60
#define ICR_EOI_SET_PRIORITY 0xc0
/* Macros to enable/disable IRQs */
#define IMR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_IMR : PIC2_IMR )
#define IMR_BIT(x) ( 1 << ( (x) % IRQ_PIC_CUTOFF ) )
#define irq_enabled(x) ( ( inb ( IMR_REG(x) ) & IMR_BIT(x) ) == 0 )
#define enable_irq(x) outb ( inb( IMR_REG(x) ) & ~IMR_BIT(x), IMR_REG(x) )
#define disable_irq(x) outb ( inb( IMR_REG(x) ) | IMR_BIT(x), IMR_REG(x) )
/* Macros for acknowledging IRQs */
#define ICR_REG( irq ) ( (irq) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
#define ICR_VALUE( irq ) ( (irq) % IRQ_PIC_CUTOFF )
#define CHAINED_IRQ 2
/* Utility macros to convert IRQ numbers to INT numbers and INT vectors */
#define IRQ_INT( irq ) ( ( ( (irq) - IRQ_PIC_CUTOFF ) ^ 0x70 ) & 0x7f )
/* Other constants */
#define IRQ_MAX 15
#define IRQ_NONE -1U
/* Function prototypes
*/
void send_eoi ( unsigned int irq );
#endif /* PIC8259_H */