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xen_ipi.c revision 1.20.10.1 
      1 /* $NetBSD: xen_ipi.c,v 1.20.10.1 2021/04/30 14:22:24 martin 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 1.20.10.1 2021/04/30 14:22:24 martin Exp $");
     37  */
     38 
     39 __KERNEL_RCSID(0, "$NetBSD: xen_ipi.c,v 1.20.10.1 2021/04/30 14:22:24 martin Exp $");
     40 
     41 #include "opt_ddb.h"
     42 
     43 #include <sys/types.h>
     44 
     45 #include <sys/atomic.h>
     46 #include <sys/cpu.h>
     47 #include <sys/mutex.h>
     48 #include <sys/device.h>
     49 #include <sys/xcall.h>
     50 #include <sys/ipi.h>
     51 #include <sys/errno.h>
     52 #include <sys/systm.h>
     53 
     54 #include <x86/fpu.h>
     55 #include <machine/frame.h>
     56 #include <machine/segments.h>
     57 
     58 #include <xen/evtchn.h>
     59 #include <xen/intr.h>
     60 #include <xen/intrdefs.h>
     61 #include <xen/hypervisor.h>
     62 #include <xen/xen-public/vcpu.h>
     63 
     64 #ifdef DDB
     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 static void xen_ipi_ddb(struct cpu_info *, struct intrframe *);
     71 #endif
     72 
     73 static void xen_ipi_halt(struct cpu_info *, struct intrframe *);
     74 static void xen_ipi_synch_fpu(struct cpu_info *, struct intrframe *);
     75 static void xen_ipi_xcall(struct cpu_info *, struct intrframe *);
     76 static void xen_ipi_hvcb(struct cpu_info *, struct intrframe *);
     77 static void xen_ipi_generic(struct cpu_info *, struct intrframe *);
     78 
     79 static void (*ipifunc[XEN_NIPIS])(struct cpu_info *, struct intrframe *) =
     80 {	/* In order of priority (see: xen/include/intrdefs.h */
     81 	xen_ipi_halt,
     82 	xen_ipi_synch_fpu,
     83 #ifdef DDB
     84 	xen_ipi_ddb,
     85 #else
     86 	NULL,
     87 #endif
     88 	xen_ipi_xcall,
     89 	xen_ipi_hvcb,
     90 	xen_ipi_generic,
     91 };
     92 
     93 static void
     94 xen_ipi_handler(struct cpu_info *ci, struct intrframe *regs)
     95 {
     96 	uint32_t pending;
     97 	int bit;
     98 
     99 	pending = atomic_swap_32(&ci->ci_ipis, 0);
    100 
    101 	KDASSERT((pending >> XEN_NIPIS) == 0);
    102 	while ((bit = ffs(pending)) != 0) {
    103 		bit--;
    104 		pending &= ~(1 << bit);
    105 		ci->ci_ipi_events[bit].ev_count++;
    106 		if (ipifunc[bit] != NULL) {
    107 			(*ipifunc[bit])(ci, regs);
    108 		} else {
    109 			panic("ipifunc[%d] unsupported!\n", bit);
    110 			/* NOTREACHED */
    111 		}
    112 	}
    113 }
    114 
    115 /* Must be called once for every cpu that expects to send/recv ipis */
    116 void
    117 xen_ipi_init(void)
    118 {
    119 	cpuid_t vcpu;
    120 	evtchn_port_t evtchn;
    121 	struct cpu_info *ci;
    122 
    123 	ci = curcpu();
    124 
    125 	vcpu = ci->ci_cpuid;
    126 	KASSERT(vcpu < XEN_LEGACY_MAX_VCPUS);
    127 
    128 	evtchn = bind_vcpu_to_evtch(vcpu);
    129 	ci->ci_ipi_evtchn = evtchn;
    130 
    131 	KASSERT(evtchn != -1 && evtchn < NR_EVENT_CHANNELS);
    132 
    133 	if (0 != event_set_handler(evtchn, (int (*)(void *))xen_ipi_handler,
    134 				   ci, IPL_HIGH, "ipi")) {
    135 		panic("event_set_handler(...) KPI violation\n");
    136 		/* NOTREACHED */
    137 	}
    138 
    139 	hypervisor_enable_event(evtchn);
    140 }
    141 
    142 #ifdef DIAGNOSTIC
    143 static inline bool /* helper */
    144 valid_ipimask(uint32_t ipimask)
    145 {
    146 	uint32_t masks = XEN_IPI_GENERIC | XEN_IPI_HVCB | XEN_IPI_XCALL |
    147 		 XEN_IPI_DDB | XEN_IPI_SYNCH_FPU |
    148 		 XEN_IPI_HALT | XEN_IPI_KICK;
    149 
    150 	if (ipimask & ~masks) {
    151 		return false;
    152 	} else {
    153 		return true;
    154 	}
    155 
    156 }
    157 #endif
    158 
    159 int
    160 xen_send_ipi(struct cpu_info *ci, uint32_t ipimask)
    161 {
    162 	evtchn_port_t evtchn;
    163 
    164 	KASSERT(ci != NULL || ci != curcpu());
    165 
    166 	if ((ci->ci_flags & CPUF_RUNNING) == 0) {
    167 		return ENOENT;
    168 	}
    169 
    170 	evtchn = ci->ci_ipi_evtchn;
    171 
    172 	KASSERTMSG(valid_ipimask(ipimask) == true,
    173 		"xen_send_ipi() called with invalid ipimask\n");
    174 
    175 	atomic_or_32(&ci->ci_ipis, ipimask);
    176 	hypervisor_notify_via_evtchn(evtchn);
    177 
    178 	return 0;
    179 }
    180 
    181 void
    182 xen_broadcast_ipi(uint32_t ipimask)
    183 {
    184 	struct cpu_info *ci, *self = curcpu();
    185 	CPU_INFO_ITERATOR cii;
    186 
    187 	KASSERTMSG(valid_ipimask(ipimask) == true,
    188 		"xen_broadcast_ipi() called with invalid ipimask\n");
    189 
    190 	/*
    191 	 * XXX-cherry: there's an implicit broadcast sending order
    192 	 * which I dislike. Randomise this ? :-)
    193 	 */
    194 
    195 	for (CPU_INFO_FOREACH(cii, ci)) {
    196 		if (ci == NULL)
    197 			continue;
    198 		if (ci == self)
    199 			continue;
    200 		if (ci->ci_data.cpu_idlelwp == NULL)
    201 			continue;
    202 		if ((ci->ci_flags & CPUF_PRESENT) == 0)
    203 			continue;
    204 		if (ci->ci_flags & (CPUF_RUNNING)) {
    205 			if (0 != xen_send_ipi(ci, ipimask)) {
    206 				panic("xen_ipi of %x from %s to %s failed\n",
    207 				      ipimask, cpu_name(curcpu()),
    208 				      cpu_name(ci));
    209 			}
    210 		}
    211 	}
    212 }
    213 
    214 /* MD wrapper for the xcall(9) callback. */
    215 #define PRIuCPUID	"lu" /* XXX: move this somewhere more appropriate */
    216 
    217 static void
    218 xen_ipi_halt(struct cpu_info *ci, struct intrframe *intrf)
    219 {
    220 	KASSERT(ci == curcpu());
    221 	KASSERT(ci != NULL);
    222 	if (HYPERVISOR_vcpu_op(VCPUOP_down, ci->ci_cpuid, NULL)) {
    223 		panic("vcpu%" PRIuCPUID "shutdown failed.\n", ci->ci_cpuid);
    224 	}
    225 
    226 }
    227 
    228 static void
    229 xen_ipi_synch_fpu(struct cpu_info *ci, struct intrframe *intrf)
    230 {
    231 	KASSERT(ci != NULL);
    232 	KASSERT(intrf != NULL);
    233 
    234 	fpusave_cpu(true);
    235 }
    236 
    237 #ifdef DDB
    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 #endif /* DDB */
    277 
    278 static void
    279 xen_ipi_xcall(struct cpu_info *ci, struct intrframe *intrf)
    280 {
    281 	KASSERT(ci != NULL);
    282 	KASSERT(intrf != NULL);
    283 
    284 	xc_ipi_handler();
    285 }
    286 
    287 void
    288 xc_send_ipi(struct cpu_info *ci)
    289 {
    290 
    291 	KASSERT(kpreempt_disabled());
    292 	KASSERT(curcpu() != ci);
    293 	if (ci) {
    294 		if (0 != xen_send_ipi(ci, XEN_IPI_XCALL)) {
    295 			panic("xen_send_ipi(XEN_IPI_XCALL) failed\n");
    296 		}
    297 	} else {
    298 		xen_broadcast_ipi(XEN_IPI_XCALL);
    299 	}
    300 }
    301 
    302 static void
    303 xen_ipi_generic(struct cpu_info *ci, struct intrframe *intrf)
    304 {
    305 	KASSERT(ci != NULL);
    306 	KASSERT(intrf != NULL);
    307 
    308 	ipi_cpu_handler();
    309 }
    310 
    311 void
    312 cpu_ipi(struct cpu_info *ci)
    313 {
    314 	KASSERT(kpreempt_disabled());
    315 	KASSERT(curcpu() != ci);
    316 	if (ci) {
    317 		if (0 != xen_send_ipi(ci, XEN_IPI_GENERIC)) {
    318 			panic("xen_send_ipi(XEN_IPI_GENERIC) failed\n");
    319 		}
    320 	} else {
    321 		xen_broadcast_ipi(XEN_IPI_GENERIC);
    322 	}
    323 }
    324 
    325 static void
    326 xen_ipi_hvcb(struct cpu_info *ci, struct intrframe *intrf)
    327 {
    328 	KASSERT(ci != NULL);
    329 	KASSERT(intrf != NULL);
    330 	KASSERT(ci == curcpu());
    331 	KASSERT(!ci->ci_vcpu->evtchn_upcall_mask);
    332 
    333 	hypervisor_force_callback();
    334 }
    335