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xen_ipi.c revision 1.18.2.1 
      1 /* $NetBSD: xen_ipi.c,v 1.18.2.1 2015/02/08 22:18:30 snj 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 1.18.2.1 2015/02/08 22:18:30 snj Exp $");
     37  */
     38 
     39 __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.18.2.1 2015/02/08 22:18:30 snj 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/ipi.h>
     49 #include <sys/errno.h>
     50 #include <sys/systm.h>
     51 
     52 #include <x86/fpu.h>
     53 #include <machine/frame.h>
     54 #include <machine/segments.h>
     55 
     56 #include <xen/evtchn.h>
     57 #include <xen/intr.h>
     58 #include <xen/intrdefs.h>
     59 #include <xen/hypervisor.h>
     60 #include <xen/xen-public/vcpu.h>
     61 
     62 #ifdef __x86_64__
     63 extern void ddb_ipi(struct trapframe);
     64 #else
     65 extern void ddb_ipi(int, struct trapframe);
     66 #endif /* __x86_64__ */
     67 
     68 static void xen_ipi_halt(struct cpu_info *, struct intrframe *);
     69 static void xen_ipi_synch_fpu(struct cpu_info *, struct intrframe *);
     70 static void xen_ipi_ddb(struct cpu_info *, struct intrframe *);
     71 static void xen_ipi_xcall(struct cpu_info *, struct intrframe *);
     72 static void xen_ipi_hvcb(struct cpu_info *, struct intrframe *);
     73 static void xen_ipi_generic(struct cpu_info *, struct intrframe *);
     74 
     75 static void (*ipifunc[XEN_NIPIS])(struct cpu_info *, struct intrframe *) =
     76 {	/* In order of priority (see: xen/include/intrdefs.h */
     77 	xen_ipi_halt,
     78 	xen_ipi_synch_fpu,
     79 	xen_ipi_ddb,
     80 	xen_ipi_xcall,
     81 	xen_ipi_hvcb,
     82 	xen_ipi_generic,
     83 };
     84 
     85 static void
     86 xen_ipi_handler(struct cpu_info *ci, struct intrframe *regs)
     87 {
     88 	uint32_t pending;
     89 	int bit;
     90 
     91 	pending = atomic_swap_32(&ci->ci_ipis, 0);
     92 
     93 	KDASSERT((pending >> XEN_NIPIS) == 0);
     94 	while ((bit = ffs(pending)) != 0) {
     95 		bit--;
     96 		pending &= ~(1 << bit);
     97 		ci->ci_ipi_events[bit].ev_count++;
     98 		if (ipifunc[bit] != NULL) {
     99 			(*ipifunc[bit])(ci, regs);
    100 		} else {
    101 			panic("ipifunc[%d] unsupported!\n", bit);
    102 			/* NOTREACHED */
    103 		}
    104 	}
    105 }
    106 
    107 /* Must be called once for every cpu that expects to send/recv ipis */
    108 void
    109 xen_ipi_init(void)
    110 {
    111 	cpuid_t vcpu;
    112 	evtchn_port_t evtchn;
    113 	struct cpu_info *ci;
    114 
    115 	ci = curcpu();
    116 
    117 	vcpu = ci->ci_cpuid;
    118 	KASSERT(vcpu < XEN_LEGACY_MAX_VCPUS);
    119 
    120 	evtchn = bind_vcpu_to_evtch(vcpu);
    121 	ci->ci_ipi_evtchn = evtchn;
    122 
    123 	KASSERT(evtchn != -1 && evtchn < NR_EVENT_CHANNELS);
    124 
    125 	if (0 != event_set_handler(evtchn, (int (*)(void *))xen_ipi_handler,
    126 				   ci, IPL_HIGH, "ipi")) {
    127 		panic("event_set_handler(...) KPI violation\n");
    128 		/* NOTREACHED */
    129 	}
    130 
    131 	hypervisor_enable_event(evtchn);
    132 }
    133 
    134 #ifdef DIAGNOSTIC
    135 static inline bool /* helper */
    136 valid_ipimask(uint32_t ipimask)
    137 {
    138 	uint32_t masks = XEN_IPI_GENERIC | XEN_IPI_HVCB | XEN_IPI_XCALL |
    139 		 XEN_IPI_DDB | XEN_IPI_SYNCH_FPU |
    140 		 XEN_IPI_HALT | XEN_IPI_KICK;
    141 
    142 	if (ipimask & ~masks) {
    143 		return false;
    144 	} else {
    145 		return true;
    146 	}
    147 
    148 }
    149 #endif
    150 
    151 int
    152 xen_send_ipi(struct cpu_info *ci, uint32_t ipimask)
    153 {
    154 	evtchn_port_t evtchn;
    155 
    156 	KASSERT(ci != NULL || ci != curcpu());
    157 
    158 	if ((ci->ci_flags & CPUF_RUNNING) == 0) {
    159 		return ENOENT;
    160 	}
    161 
    162 	evtchn = ci->ci_ipi_evtchn;
    163 
    164 	KASSERTMSG(valid_ipimask(ipimask) == true,
    165 		"xen_send_ipi() called with invalid ipimask\n");
    166 
    167 	atomic_or_32(&ci->ci_ipis, ipimask);
    168 	hypervisor_notify_via_evtchn(evtchn);
    169 
    170 	return 0;
    171 }
    172 
    173 void
    174 xen_broadcast_ipi(uint32_t ipimask)
    175 {
    176 	struct cpu_info *ci, *self = curcpu();
    177 	CPU_INFO_ITERATOR cii;
    178 
    179 	KASSERTMSG(valid_ipimask(ipimask) == true,
    180 		"xen_broadcast_ipi() called with invalid ipimask\n");
    181 
    182 	/*
    183 	 * XXX-cherry: there's an implicit broadcast sending order
    184 	 * which I dislike. Randomise this ? :-)
    185 	 */
    186 
    187 	for (CPU_INFO_FOREACH(cii, ci)) {
    188 		if (ci == NULL)
    189 			continue;
    190 		if (ci == self)
    191 			continue;
    192 		if (ci->ci_data.cpu_idlelwp == NULL)
    193 			continue;
    194 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
    195 			continue;
    196 		if (ci->ci_flags & (CPUF_RUNNING)) {
    197 			if (0 != xen_send_ipi(ci, ipimask)) {
    198 				panic("xen_ipi of %x from %s to %s failed\n",
    199 				      ipimask, cpu_name(curcpu()),
    200 				      cpu_name(ci));
    201 			}
    202 		}
    203 	}
    204 }
    205 
    206 /* MD wrapper for the xcall(9) callback. */
    207 #define PRIuCPUID	"lu" /* XXX: move this somewhere more appropriate */
    208 
    209 static void
    210 xen_ipi_halt(struct cpu_info *ci, struct intrframe *intrf)
    211 {
    212 	KASSERT(ci == curcpu());
    213 	KASSERT(ci != NULL);
    214 	if (HYPERVISOR_vcpu_op(VCPUOP_down, ci->ci_cpuid, NULL)) {
    215 		panic("vcpu%" PRIuCPUID "shutdown failed.\n", ci->ci_cpuid);
    216 	}
    217 
    218 }
    219 
    220 static void
    221 xen_ipi_synch_fpu(struct cpu_info *ci, struct intrframe *intrf)
    222 {
    223 	KASSERT(ci != NULL);
    224 	KASSERT(intrf != NULL);
    225 
    226 	fpusave_cpu(true);
    227 }
    228 
    229 static void
    230 xen_ipi_ddb(struct cpu_info *ci, struct intrframe *intrf)
    231 {
    232 	KASSERT(ci != NULL);
    233 	KASSERT(intrf != NULL);
    234 
    235 #ifdef __x86_64__
    236 	ddb_ipi(intrf->if_tf);
    237 #else
    238 	struct trapframe tf;
    239 	tf.tf_gs = intrf->if_gs;
    240 	tf.tf_fs = intrf->if_fs;
    241 	tf.tf_es = intrf->if_es;
    242 	tf.tf_ds = intrf->if_ds;
    243 	tf.tf_edi = intrf->if_edi;
    244 	tf.tf_esi = intrf->if_esi;
    245 	tf.tf_ebp = intrf->if_ebp;
    246 	tf.tf_ebx = intrf->if_ebx;
    247 	tf.tf_ecx = intrf->if_ecx;
    248 	tf.tf_eax = intrf->if_eax;
    249 	tf.tf_trapno = intrf->__if_trapno;
    250 	tf.tf_err = intrf->__if_err;
    251 	tf.tf_eip = intrf->if_eip;
    252 	tf.tf_cs = intrf->if_cs;
    253 	tf.tf_eflags = intrf->if_eflags;
    254 	tf.tf_esp = intrf->if_esp;
    255 	tf.tf_ss = intrf->if_ss;
    256 
    257 	/* XXX: does i386/Xen have vm86 support ?
    258 	tf.tf_vm86_es;
    259 	tf.tf_vm86_ds;
    260 	tf.tf_vm86_fs;
    261 	tf.tf_vm86_gs;
    262 	   :XXX */
    263 
    264 	ddb_ipi(SEL_KPL, tf);
    265 #endif
    266 }
    267 
    268 static void
    269 xen_ipi_xcall(struct cpu_info *ci, struct intrframe *intrf)
    270 {
    271 	KASSERT(ci != NULL);
    272 	KASSERT(intrf != NULL);
    273 
    274 	xc_ipi_handler();
    275 }
    276 
    277 void
    278 xc_send_ipi(struct cpu_info *ci)
    279 {
    280 
    281 	KASSERT(kpreempt_disabled());
    282 	KASSERT(curcpu() != ci);
    283 	if (ci) {
    284 		if (0 != xen_send_ipi(ci, XEN_IPI_XCALL)) {
    285 			panic("xen_send_ipi(XEN_IPI_XCALL) failed\n");
    286 		}
    287 	} else {
    288 		xen_broadcast_ipi(XEN_IPI_XCALL);
    289 	}
    290 }
    291 
    292 static void
    293 xen_ipi_generic(struct cpu_info *ci, struct intrframe *intrf)
    294 {
    295 	KASSERT(ci != NULL);
    296 	KASSERT(intrf != NULL);
    297 
    298 	ipi_cpu_handler();
    299 }
    300 
    301 void
    302 cpu_ipi(struct cpu_info *ci)
    303 {
    304 	KASSERT(kpreempt_disabled());
    305 	KASSERT(curcpu() != ci);
    306 	if (ci) {
    307 		if (0 != xen_send_ipi(ci, XEN_IPI_GENERIC)) {
    308 			panic("xen_send_ipi(XEN_IPI_GENERIC) failed\n");
    309 		}
    310 	} else {
    311 		xen_broadcast_ipi(XEN_IPI_GENERIC);
    312 	}
    313 }
    314 
    315 static void
    316 xen_ipi_hvcb(struct cpu_info *ci, struct intrframe *intrf)
    317 {
    318 	KASSERT(ci != NULL);
    319 	KASSERT(intrf != NULL);
    320 	KASSERT(ci == curcpu());
    321 	KASSERT(!ci->ci_vcpu->evtchn_upcall_mask);
    322 
    323 	hypervisor_force_callback();
    324 }
    325