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xen_ipi.c revision 1.11 
      1 /* $NetBSD: xen_ipi.c,v 1.11 2012/12/27 06:42:14 cherry 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 1.11 2012/12/27 06:42:14 cherry Exp $");
     37  */
     38 
     39 __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.11 2012/12/27 06:42:14 cherry 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 #ifdef __x86_64__
     52 #include <machine/fpu.h>
     53 #else
     54 #include <machine/npx.h>
     55 #endif /* __x86_64__ */
     56 #include <machine/frame.h>
     57 #include <machine/segments.h>
     58 
     59 #include <xen/evtchn.h>
     60 #include <xen/intr.h>
     61 #include <xen/intrdefs.h>
     62 #include <xen/hypervisor.h>
     63 #include <xen/xen-public/vcpu.h>
     64 
     65 #ifdef __x86_64__
     66 extern void ddb_ipi(struct trapframe);
     67 #else
     68 extern void ddb_ipi(int, struct trapframe);
     69 #endif /* __x86_64__ */
     70 
     71 static void xen_ipi_halt(struct cpu_info *, struct intrframe *);
     72 static void xen_ipi_synch_fpu(struct cpu_info *, struct intrframe *);
     73 static void xen_ipi_ddb(struct cpu_info *, struct intrframe *);
     74 static void xen_ipi_xcall(struct cpu_info *, struct intrframe *);
     75 static void xen_ipi_hvcb(struct cpu_info *, struct intrframe *);
     76 
     77 static void (*ipifunc[XEN_NIPIS])(struct cpu_info *, struct intrframe *) =
     78 {	/* In order of priority (see: xen/include/intrdefs.h */
     79 	xen_ipi_halt,
     80 	xen_ipi_synch_fpu,
     81 	xen_ipi_ddb,
     82 	xen_ipi_xcall,
     83 	xen_ipi_hvcb
     84 };
     85 
     86 static void
     87 xen_ipi_handler(struct cpu_info *ci, struct intrframe *regs)
     88 {
     89 	uint32_t pending;
     90 	int bit;
     91 
     92 	pending = atomic_swap_32(&ci->ci_ipis, 0);
     93 
     94 	KDASSERT((pending >> XEN_NIPIS) == 0);
     95 	while ((bit = ffs(pending)) != 0) {
     96 		bit--;
     97 		pending &= ~(1 << bit);
     98 		ci->ci_ipi_events[bit].ev_count++;
     99 		if (ipifunc[bit] != NULL) {
    100 			(*ipifunc[bit])(ci, regs);
    101 		} else {
    102 			panic("ipifunc[%d] unsupported!\n", bit);
    103 			/* NOTREACHED */
    104 		}
    105 	}
    106 }
    107 
    108 /* Must be called once for every cpu that expects to send/recv ipis */
    109 void
    110 xen_ipi_init(void)
    111 {
    112 	cpuid_t vcpu;
    113 	evtchn_port_t evtchn;
    114 	struct cpu_info *ci;
    115 
    116 	ci = curcpu();
    117 
    118 	vcpu = ci->ci_cpuid;
    119 	KASSERT(vcpu < XEN_LEGACY_MAX_VCPUS);
    120 
    121 	evtchn = bind_vcpu_to_evtch(vcpu);
    122 	ci->ci_ipi_evtchn = evtchn;
    123 
    124 	KASSERT(evtchn != -1 && evtchn < NR_EVENT_CHANNELS);
    125 
    126 	if (0 != event_set_handler(evtchn, (int (*)(void *))xen_ipi_handler,
    127 				   ci, IPL_HIGH, "ipi")) {
    128 		panic("event_set_handler(...) KPI violation\n");
    129 		/* NOTREACHED */
    130 	}
    131 
    132 	hypervisor_enable_event(evtchn);
    133 }
    134 
    135 /* prefer this to global variable */
    136 static inline u_int max_cpus(void)
    137 {
    138 	return maxcpus;
    139 }
    140 
    141 static inline bool /* helper */
    142 valid_ipimask(uint32_t ipimask)
    143 {
    144 	uint32_t masks =  XEN_IPI_HVCB | XEN_IPI_XCALL |
    145 		 XEN_IPI_DDB | XEN_IPI_SYNCH_FPU |
    146 		 XEN_IPI_HALT | XEN_IPI_KICK;
    147 
    148 	if (ipimask & ~masks) {
    149 		return false;
    150 	} else {
    151 		return true;
    152 	}
    153 
    154 }
    155 
    156 int
    157 xen_send_ipi(struct cpu_info *ci, uint32_t ipimask)
    158 {
    159 	evtchn_port_t evtchn;
    160 
    161 	KASSERT(ci != NULL || ci != curcpu());
    162 
    163 	if ((ci->ci_flags & CPUF_RUNNING) == 0) {
    164 		return ENOENT;
    165 	}
    166 
    167 	evtchn = ci->ci_ipi_evtchn;
    168 
    169 	KASSERTMSG(valid_ipimask(ipimask) == true,
    170 		"xen_send_ipi() called with invalid ipimask\n");
    171 
    172 	atomic_or_32(&ci->ci_ipis, ipimask);
    173 	hypervisor_notify_via_evtchn(evtchn);
    174 
    175 	return 0;
    176 }
    177 
    178 void
    179 xen_broadcast_ipi(uint32_t ipimask)
    180 {
    181 	struct cpu_info *ci, *self = curcpu();
    182 	CPU_INFO_ITERATOR cii;
    183 
    184 	KASSERTMSG(valid_ipimask(ipimask) == true,
    185 		"xen_broadcast_ipi() called with invalid ipimask\n");
    186 
    187 	/*
    188 	 * XXX-cherry: there's an implicit broadcast sending order
    189 	 * which I dislike. Randomise this ? :-)
    190 	 */
    191 
    192 	for (CPU_INFO_FOREACH(cii, ci)) {
    193 		if (ci == NULL)
    194 			continue;
    195 		if (ci == self)
    196 			continue;
    197 		if (ci->ci_data.cpu_idlelwp == NULL)
    198 			continue;
    199 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
    200 			continue;
    201 		if (ci->ci_flags & (CPUF_RUNNING)) {
    202 			if (0 != xen_send_ipi(ci, ipimask)) {
    203 				panic("xen_ipi of %x from %s to %s failed\n",
    204 				      ipimask, cpu_name(curcpu()),
    205 				      cpu_name(ci));
    206 			}
    207 		}
    208 	}
    209 }
    210 
    211 /* MD wrapper for the xcall(9) callback. */
    212 #define PRIuCPUID	"lu" /* XXX: move this somewhere more appropriate */
    213 
    214 static void
    215 xen_ipi_halt(struct cpu_info *ci, struct intrframe *intrf)
    216 {
    217 	KASSERT(ci == curcpu());
    218 	KASSERT(ci != NULL);
    219 	if (HYPERVISOR_vcpu_op(VCPUOP_down, ci->ci_cpuid, NULL)) {
    220 		panic("vcpu%" PRIuCPUID "shutdown failed.\n", ci->ci_cpuid);
    221 	}
    222 
    223 }
    224 
    225 static void
    226 xen_ipi_synch_fpu(struct cpu_info *ci, struct intrframe *intrf)
    227 {
    228 	KASSERT(ci != NULL);
    229 	KASSERT(intrf != NULL);
    230 
    231 #ifdef __x86_64__
    232 	fpusave_cpu(true);
    233 #else
    234 	npxsave_cpu(true);
    235 #endif /* __x86_64__ */
    236 }
    237 
    238 static void
    239 xen_ipi_ddb(struct cpu_info *ci, struct intrframe *intrf)
    240 {
    241 	KASSERT(ci != NULL);
    242 	KASSERT(intrf != NULL);
    243 
    244 #ifdef __x86_64__
    245 	ddb_ipi(intrf->if_tf);
    246 #else
    247 	struct trapframe tf;
    248 	tf.tf_gs = intrf->if_gs;
    249 	tf.tf_fs = intrf->if_fs;
    250 	tf.tf_es = intrf->if_es;
    251 	tf.tf_ds = intrf->if_ds;
    252 	tf.tf_edi = intrf->if_edi;
    253 	tf.tf_esi = intrf->if_esi;
    254 	tf.tf_ebp = intrf->if_ebp;
    255 	tf.tf_ebx = intrf->if_ebx;
    256 	tf.tf_ecx = intrf->if_ecx;
    257 	tf.tf_eax = intrf->if_eax;
    258 	tf.tf_trapno = intrf->__if_trapno;
    259 	tf.tf_err = intrf->__if_err;
    260 	tf.tf_eip = intrf->if_eip;
    261 	tf.tf_cs = intrf->if_cs;
    262 	tf.tf_eflags = intrf->if_eflags;
    263 	tf.tf_esp = intrf->if_esp;
    264 	tf.tf_ss = intrf->if_ss;
    265 
    266 	/* XXX: does i386/Xen have vm86 support ?
    267 	tf.tf_vm86_es;
    268 	tf.tf_vm86_ds;
    269 	tf.tf_vm86_fs;
    270 	tf.tf_vm86_gs;
    271 	   :XXX */
    272 
    273 	ddb_ipi(SEL_KPL, tf);
    274 #endif
    275 }
    276 
    277 static void
    278 xen_ipi_xcall(struct cpu_info *ci, struct intrframe *intrf)
    279 {
    280 	KASSERT(ci != NULL);
    281 	KASSERT(intrf != NULL);
    282 
    283 	xc_ipi_handler();
    284 }
    285 
    286 void
    287 xc_send_ipi(struct cpu_info *ci)
    288 {
    289 
    290 	KASSERT(kpreempt_disabled());
    291 	KASSERT(curcpu() != ci);
    292 	if (ci) {
    293 		if (0 != xen_send_ipi(ci, XEN_IPI_XCALL)) {
    294 			panic("xen_send_ipi(XEN_IPI_XCALL) failed\n");
    295 		}
    296 	} else {
    297 		xen_broadcast_ipi(XEN_IPI_XCALL);
    298 	}
    299 }
    300 
    301 static void
    302 xen_ipi_hvcb(struct cpu_info *ci, struct intrframe *intrf)
    303 {
    304 	KASSERT(ci != NULL);
    305 	KASSERT(intrf != NULL);
    306 	KASSERT(ci == curcpu());
    307 	KASSERT(!ci->ci_vcpu->evtchn_upcall_mask);
    308 
    309 	hypervisor_force_callback();
    310 }
    311