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xen_ipi.c revision 1.18 
      1 /* $NetBSD: xen_ipi.c,v 1.18 2014/05/19 22:47:54 rmind 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 2014/05/19 22:47:54 rmind Exp $");
     37  */
     38 
     39 __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.18 2014/05/19 22:47:54 rmind 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 static inline bool /* helper */
    135 valid_ipimask(uint32_t ipimask)
    136 {
    137 	uint32_t masks = XEN_IPI_GENERIC | XEN_IPI_HVCB | XEN_IPI_XCALL |
    138 		 XEN_IPI_DDB | XEN_IPI_SYNCH_FPU |
    139 		 XEN_IPI_HALT | XEN_IPI_KICK;
    140 
    141 	if (ipimask & ~masks) {
    142 		return false;
    143 	} else {
    144 		return true;
    145 	}
    146 
    147 }
    148 
    149 int
    150 xen_send_ipi(struct cpu_info *ci, uint32_t ipimask)
    151 {
    152 	evtchn_port_t evtchn;
    153 
    154 	KASSERT(ci != NULL || ci != curcpu());
    155 
    156 	if ((ci->ci_flags & CPUF_RUNNING) == 0) {
    157 		return ENOENT;
    158 	}
    159 
    160 	evtchn = ci->ci_ipi_evtchn;
    161 
    162 	KASSERTMSG(valid_ipimask(ipimask) == true,
    163 		"xen_send_ipi() called with invalid ipimask\n");
    164 
    165 	atomic_or_32(&ci->ci_ipis, ipimask);
    166 	hypervisor_notify_via_evtchn(evtchn);
    167 
    168 	return 0;
    169 }
    170 
    171 void
    172 xen_broadcast_ipi(uint32_t ipimask)
    173 {
    174 	struct cpu_info *ci, *self = curcpu();
    175 	CPU_INFO_ITERATOR cii;
    176 
    177 	KASSERTMSG(valid_ipimask(ipimask) == true,
    178 		"xen_broadcast_ipi() called with invalid ipimask\n");
    179 
    180 	/*
    181 	 * XXX-cherry: there's an implicit broadcast sending order
    182 	 * which I dislike. Randomise this ? :-)
    183 	 */
    184 
    185 	for (CPU_INFO_FOREACH(cii, ci)) {
    186 		if (ci == NULL)
    187 			continue;
    188 		if (ci == self)
    189 			continue;
    190 		if (ci->ci_data.cpu_idlelwp == NULL)
    191 			continue;
    192 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
    193 			continue;
    194 		if (ci->ci_flags & (CPUF_RUNNING)) {
    195 			if (0 != xen_send_ipi(ci, ipimask)) {
    196 				panic("xen_ipi of %x from %s to %s failed\n",
    197 				      ipimask, cpu_name(curcpu()),
    198 				      cpu_name(ci));
    199 			}
    200 		}
    201 	}
    202 }
    203 
    204 /* MD wrapper for the xcall(9) callback. */
    205 #define PRIuCPUID	"lu" /* XXX: move this somewhere more appropriate */
    206 
    207 static void
    208 xen_ipi_halt(struct cpu_info *ci, struct intrframe *intrf)
    209 {
    210 	KASSERT(ci == curcpu());
    211 	KASSERT(ci != NULL);
    212 	if (HYPERVISOR_vcpu_op(VCPUOP_down, ci->ci_cpuid, NULL)) {
    213 		panic("vcpu%" PRIuCPUID "shutdown failed.\n", ci->ci_cpuid);
    214 	}
    215 
    216 }
    217 
    218 static void
    219 xen_ipi_synch_fpu(struct cpu_info *ci, struct intrframe *intrf)
    220 {
    221 	KASSERT(ci != NULL);
    222 	KASSERT(intrf != NULL);
    223 
    224 	fpusave_cpu(true);
    225 }
    226 
    227 static void
    228 xen_ipi_ddb(struct cpu_info *ci, struct intrframe *intrf)
    229 {
    230 	KASSERT(ci != NULL);
    231 	KASSERT(intrf != NULL);
    232 
    233 #ifdef __x86_64__
    234 	ddb_ipi(intrf->if_tf);
    235 #else
    236 	struct trapframe tf;
    237 	tf.tf_gs = intrf->if_gs;
    238 	tf.tf_fs = intrf->if_fs;
    239 	tf.tf_es = intrf->if_es;
    240 	tf.tf_ds = intrf->if_ds;
    241 	tf.tf_edi = intrf->if_edi;
    242 	tf.tf_esi = intrf->if_esi;
    243 	tf.tf_ebp = intrf->if_ebp;
    244 	tf.tf_ebx = intrf->if_ebx;
    245 	tf.tf_ecx = intrf->if_ecx;
    246 	tf.tf_eax = intrf->if_eax;
    247 	tf.tf_trapno = intrf->__if_trapno;
    248 	tf.tf_err = intrf->__if_err;
    249 	tf.tf_eip = intrf->if_eip;
    250 	tf.tf_cs = intrf->if_cs;
    251 	tf.tf_eflags = intrf->if_eflags;
    252 	tf.tf_esp = intrf->if_esp;
    253 	tf.tf_ss = intrf->if_ss;
    254 
    255 	/* XXX: does i386/Xen have vm86 support ?
    256 	tf.tf_vm86_es;
    257 	tf.tf_vm86_ds;
    258 	tf.tf_vm86_fs;
    259 	tf.tf_vm86_gs;
    260 	   :XXX */
    261 
    262 	ddb_ipi(SEL_KPL, tf);
    263 #endif
    264 }
    265 
    266 static void
    267 xen_ipi_xcall(struct cpu_info *ci, struct intrframe *intrf)
    268 {
    269 	KASSERT(ci != NULL);
    270 	KASSERT(intrf != NULL);
    271 
    272 	xc_ipi_handler();
    273 }
    274 
    275 void
    276 xc_send_ipi(struct cpu_info *ci)
    277 {
    278 
    279 	KASSERT(kpreempt_disabled());
    280 	KASSERT(curcpu() != ci);
    281 	if (ci) {
    282 		if (0 != xen_send_ipi(ci, XEN_IPI_XCALL)) {
    283 			panic("xen_send_ipi(XEN_IPI_XCALL) failed\n");
    284 		}
    285 	} else {
    286 		xen_broadcast_ipi(XEN_IPI_XCALL);
    287 	}
    288 }
    289 
    290 static void
    291 xen_ipi_generic(struct cpu_info *ci, struct intrframe *intrf)
    292 {
    293 	KASSERT(ci != NULL);
    294 	KASSERT(intrf != NULL);
    295 
    296 	ipi_cpu_handler();
    297 }
    298 
    299 void
    300 cpu_ipi(struct cpu_info *ci)
    301 {
    302 	KASSERT(kpreempt_disabled());
    303 	KASSERT(curcpu() != ci);
    304 	if (ci) {
    305 		if (0 != xen_send_ipi(ci, XEN_IPI_GENERIC)) {
    306 			panic("xen_send_ipi(XEN_IPI_GENERIC) failed\n");
    307 		}
    308 	} else {
    309 		xen_broadcast_ipi(XEN_IPI_GENERIC);
    310 	}
    311 }
    312 
    313 static void
    314 xen_ipi_hvcb(struct cpu_info *ci, struct intrframe *intrf)
    315 {
    316 	KASSERT(ci != NULL);
    317 	KASSERT(intrf != NULL);
    318 	KASSERT(ci == curcpu());
    319 	KASSERT(!ci->ci_vcpu->evtchn_upcall_mask);
    320 
    321 	hypervisor_force_callback();
    322 }
    323