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xen_ipi.c revision 1.5.2.4
      1 /* $NetBSD: xen_ipi.c,v 1.5.2.4 2014/05/22 11:40:14 yamt Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2011 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Cherry G. Mathew <cherry (at) zyx.in>
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>			/* RCS ID macro */
     33 
     34 /*
     35  * Based on: x86/ipi.c
     36  * __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.5.2.4 2014/05/22 11:40:14 yamt Exp $");
     37  */
     38 
     39 __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.5.2.4 2014/05/22 11:40:14 yamt Exp $");
     40 
     41 #include <sys/types.h>
     42 
     43 #include <sys/atomic.h>
     44 #include <sys/cpu.h>
     45 #include <sys/mutex.h>
     46 #include <sys/device.h>
     47 #include <sys/xcall.h>
     48 #include <sys/errno.h>
     49 #include <sys/systm.h>
     50 
     51 #include <x86/fpu.h>
     52 #include <machine/frame.h>
     53 #include <machine/segments.h>
     54 
     55 #include <xen/evtchn.h>
     56 #include <xen/intr.h>
     57 #include <xen/intrdefs.h>
     58 #include <xen/hypervisor.h>
     59 #include <xen/xen-public/vcpu.h>
     60 
     61 #ifdef __x86_64__
     62 extern void ddb_ipi(struct trapframe);
     63 #else
     64 extern void ddb_ipi(int, struct trapframe);
     65 #endif /* __x86_64__ */
     66 
     67 static void xen_ipi_halt(struct cpu_info *, struct intrframe *);
     68 static void xen_ipi_synch_fpu(struct cpu_info *, struct intrframe *);
     69 static void xen_ipi_ddb(struct cpu_info *, struct intrframe *);
     70 static void xen_ipi_xcall(struct cpu_info *, struct intrframe *);
     71 static void xen_ipi_hvcb(struct cpu_info *, struct intrframe *);
     72 
     73 static void (*ipifunc[XEN_NIPIS])(struct cpu_info *, struct intrframe *) =
     74 {	/* In order of priority (see: xen/include/intrdefs.h */
     75 	xen_ipi_halt,
     76 	xen_ipi_synch_fpu,
     77 	xen_ipi_ddb,
     78 	xen_ipi_xcall,
     79 	xen_ipi_hvcb
     80 };
     81 
     82 static void
     83 xen_ipi_handler(struct cpu_info *ci, struct intrframe *regs)
     84 {
     85 	uint32_t pending;
     86 	int bit;
     87 
     88 	pending = atomic_swap_32(&ci->ci_ipis, 0);
     89 
     90 	KDASSERT((pending >> XEN_NIPIS) == 0);
     91 	while ((bit = ffs(pending)) != 0) {
     92 		bit--;
     93 		pending &= ~(1 << bit);
     94 		ci->ci_ipi_events[bit].ev_count++;
     95 		if (ipifunc[bit] != NULL) {
     96 			(*ipifunc[bit])(ci, regs);
     97 		} else {
     98 			panic("ipifunc[%d] unsupported!\n", bit);
     99 			/* NOTREACHED */
    100 		}
    101 	}
    102 }
    103 
    104 /* Must be called once for every cpu that expects to send/recv ipis */
    105 void
    106 xen_ipi_init(void)
    107 {
    108 	cpuid_t vcpu;
    109 	evtchn_port_t evtchn;
    110 	struct cpu_info *ci;
    111 
    112 	ci = curcpu();
    113 
    114 	vcpu = ci->ci_cpuid;
    115 	KASSERT(vcpu < XEN_LEGACY_MAX_VCPUS);
    116 
    117 	evtchn = bind_vcpu_to_evtch(vcpu);
    118 	ci->ci_ipi_evtchn = evtchn;
    119 
    120 	KASSERT(evtchn != -1 && evtchn < NR_EVENT_CHANNELS);
    121 
    122 	if (0 != event_set_handler(evtchn, (int (*)(void *))xen_ipi_handler,
    123 				   ci, IPL_HIGH, "ipi")) {
    124 		panic("event_set_handler(...) KPI violation\n");
    125 		/* NOTREACHED */
    126 	}
    127 
    128 	hypervisor_enable_event(evtchn);
    129 }
    130 
    131 static inline bool /* helper */
    132 valid_ipimask(uint32_t ipimask)
    133 {
    134 	uint32_t masks =  XEN_IPI_HVCB | XEN_IPI_XCALL |
    135 		 XEN_IPI_DDB | XEN_IPI_SYNCH_FPU |
    136 		 XEN_IPI_HALT | XEN_IPI_KICK;
    137 
    138 	if (ipimask & ~masks) {
    139 		return false;
    140 	} else {
    141 		return true;
    142 	}
    143 
    144 }
    145 
    146 int
    147 xen_send_ipi(struct cpu_info *ci, uint32_t ipimask)
    148 {
    149 	evtchn_port_t evtchn;
    150 
    151 	KASSERT(ci != NULL || ci != curcpu());
    152 
    153 	if ((ci->ci_flags & CPUF_RUNNING) == 0) {
    154 		return ENOENT;
    155 	}
    156 
    157 	evtchn = ci->ci_ipi_evtchn;
    158 
    159 	KASSERTMSG(valid_ipimask(ipimask) == true,
    160 		"xen_send_ipi() called with invalid ipimask\n");
    161 
    162 	atomic_or_32(&ci->ci_ipis, ipimask);
    163 	hypervisor_notify_via_evtchn(evtchn);
    164 
    165 	return 0;
    166 }
    167 
    168 void
    169 xen_broadcast_ipi(uint32_t ipimask)
    170 {
    171 	struct cpu_info *ci, *self = curcpu();
    172 	CPU_INFO_ITERATOR cii;
    173 
    174 	KASSERTMSG(valid_ipimask(ipimask) == true,
    175 		"xen_broadcast_ipi() called with invalid ipimask\n");
    176 
    177 	/*
    178 	 * XXX-cherry: there's an implicit broadcast sending order
    179 	 * which I dislike. Randomise this ? :-)
    180 	 */
    181 
    182 	for (CPU_INFO_FOREACH(cii, ci)) {
    183 		if (ci == NULL)
    184 			continue;
    185 		if (ci == self)
    186 			continue;
    187 		if (ci->ci_data.cpu_idlelwp == NULL)
    188 			continue;
    189 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
    190 			continue;
    191 		if (ci->ci_flags & (CPUF_RUNNING)) {
    192 			if (0 != xen_send_ipi(ci, ipimask)) {
    193 				panic("xen_ipi of %x from %s to %s failed\n",
    194 				      ipimask, cpu_name(curcpu()),
    195 				      cpu_name(ci));
    196 			}
    197 		}
    198 	}
    199 }
    200 
    201 /* MD wrapper for the xcall(9) callback. */
    202 #define PRIuCPUID	"lu" /* XXX: move this somewhere more appropriate */
    203 
    204 static void
    205 xen_ipi_halt(struct cpu_info *ci, struct intrframe *intrf)
    206 {
    207 	KASSERT(ci == curcpu());
    208 	KASSERT(ci != NULL);
    209 	if (HYPERVISOR_vcpu_op(VCPUOP_down, ci->ci_cpuid, NULL)) {
    210 		panic("vcpu%" PRIuCPUID "shutdown failed.\n", ci->ci_cpuid);
    211 	}
    212 
    213 }
    214 
    215 static void
    216 xen_ipi_synch_fpu(struct cpu_info *ci, struct intrframe *intrf)
    217 {
    218 	KASSERT(ci != NULL);
    219 	KASSERT(intrf != NULL);
    220 
    221 	fpusave_cpu(true);
    222 }
    223 
    224 static void
    225 xen_ipi_ddb(struct cpu_info *ci, struct intrframe *intrf)
    226 {
    227 	KASSERT(ci != NULL);
    228 	KASSERT(intrf != NULL);
    229 
    230 #ifdef __x86_64__
    231 	ddb_ipi(intrf->if_tf);
    232 #else
    233 	struct trapframe tf;
    234 	tf.tf_gs = intrf->if_gs;
    235 	tf.tf_fs = intrf->if_fs;
    236 	tf.tf_es = intrf->if_es;
    237 	tf.tf_ds = intrf->if_ds;
    238 	tf.tf_edi = intrf->if_edi;
    239 	tf.tf_esi = intrf->if_esi;
    240 	tf.tf_ebp = intrf->if_ebp;
    241 	tf.tf_ebx = intrf->if_ebx;
    242 	tf.tf_ecx = intrf->if_ecx;
    243 	tf.tf_eax = intrf->if_eax;
    244 	tf.tf_trapno = intrf->__if_trapno;
    245 	tf.tf_err = intrf->__if_err;
    246 	tf.tf_eip = intrf->if_eip;
    247 	tf.tf_cs = intrf->if_cs;
    248 	tf.tf_eflags = intrf->if_eflags;
    249 	tf.tf_esp = intrf->if_esp;
    250 	tf.tf_ss = intrf->if_ss;
    251 
    252 	/* XXX: does i386/Xen have vm86 support ?
    253 	tf.tf_vm86_es;
    254 	tf.tf_vm86_ds;
    255 	tf.tf_vm86_fs;
    256 	tf.tf_vm86_gs;
    257 	   :XXX */
    258 
    259 	ddb_ipi(SEL_KPL, tf);
    260 #endif
    261 }
    262 
    263 static void
    264 xen_ipi_xcall(struct cpu_info *ci, struct intrframe *intrf)
    265 {
    266 	KASSERT(ci != NULL);
    267 	KASSERT(intrf != NULL);
    268 
    269 	xc_ipi_handler();
    270 }
    271 
    272 void
    273 xc_send_ipi(struct cpu_info *ci)
    274 {
    275 
    276 	KASSERT(kpreempt_disabled());
    277 	KASSERT(curcpu() != ci);
    278 	if (ci) {
    279 		if (0 != xen_send_ipi(ci, XEN_IPI_XCALL)) {
    280 			panic("xen_send_ipi(XEN_IPI_XCALL) failed\n");
    281 		}
    282 	} else {
    283 		xen_broadcast_ipi(XEN_IPI_XCALL);
    284 	}
    285 }
    286 
    287 static void
    288 xen_ipi_hvcb(struct cpu_info *ci, struct intrframe *intrf)
    289 {
    290 	KASSERT(ci != NULL);
    291 	KASSERT(intrf != NULL);
    292 	KASSERT(ci == curcpu());
    293 	KASSERT(!ci->ci_vcpu->evtchn_upcall_mask);
    294 
    295 	hypervisor_force_callback();
    296 }
    297