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/*-
* Copyright (c) 2011 NetApp, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/bus.h>
#include <machine/intr_machdep.h>
#include <x86/apicvar.h>
#include <machine/segments.h>
#include <machine/md_var.h>
#include <machine/vmm.h>
#include "vmm_ipi.h"
extern inthand_t IDTVEC(rsvd), IDTVEC(justreturn);
CTASSERT(APIC_SPURIOUS_INT == 255);
int
vmm_ipi_alloc(void)
{
int idx;
uintptr_t func;
struct gate_descriptor *ip;
/*
* Search backwards from the highest IDT vector available for use
* as our IPI vector. We install the 'justreturn' handler at that
* vector and use it to interrupt the vcpus.
*
* We do this because the IPI_AST is heavyweight and saves all
* registers in the trapframe. This is overkill for our use case
* which is simply to EOI the interrupt and return.
*/
idx = APIC_SPURIOUS_INT;
while (--idx >= APIC_IPI_INTS) {
ip = &idt[idx];
func = ((long)ip->gd_hioffset << 16 | ip->gd_looffset);
if (func == (uintptr_t)&IDTVEC(rsvd)) {
setidt(idx , IDTVEC(justreturn), SDT_SYSIGT,
SEL_KPL, 0);
return (idx);
}
}
return (0);
}
void
vmm_ipi_free(int ipinum)
{
uintptr_t func;
struct gate_descriptor *ip;
KASSERT(ipinum >= APIC_IPI_INTS && ipinum < APIC_SPURIOUS_INT,
("invalid ipi %d", ipinum));
ip = &idt[ipinum];
func = ((long)ip->gd_hioffset << 16 | ip->gd_looffset);
KASSERT(func == (uintptr_t)&IDTVEC(justreturn),
("invalid ipi %d", ipinum));
setidt(ipinum, IDTVEC(rsvd), SDT_SYSIGT, SEL_KPL, 0);
}
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