xref: /freebsd/sys/xen/xen_common.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright © 2008, 2013 Citrix Systems, Inc.
5  * Copyright © 2012 Spectra Logic Corporation
6  * Copyright © 2021 Elliott Mitchell
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/param.h> /* required by xen/xen-os.h */
32 
33 #include <vm/vm.h>
34 #include <vm/pmap.h>
35 
36 #include <machine/atomic.h> /* required by xen/xen-os.h */
37 
38 #include <xen/xen-os.h>
39 #include <xen/hvm.h>
40 
41 #include <contrib/xen/vcpu.h>
42 
43 /*-------------------------------- Global Data -------------------------------*/
44 /**
45  * Start info flags. ATM this only used to store the initial domain flag for
46  * PVHv2, and it's always empty for HVM guests.
47  */
48 uint32_t hvm_start_flags;
49 
50 /*------------------ Hypervisor Access Shared Memory Regions -----------------*/
51 shared_info_t *HYPERVISOR_shared_info;
52 
53 /*------------------------------- Per-CPU Data -------------------------------*/
54 DPCPU_DEFINE(struct vcpu_info *, vcpu_info);
55 
56 void
57 xen_setup_vcpu_info(void)
58 {
59 	/* This isn't directly accessed outside this function */
60 	DPCPU_DEFINE_STATIC(vcpu_info_t, vcpu_local_info)
61 	    __attribute__((aligned(64)));
62 
63 	vcpu_info_t *vcpu_info = DPCPU_PTR(vcpu_local_info);
64 	vcpu_register_vcpu_info_t info = {
65 		.mfn = vtophys(vcpu_info) >> PAGE_SHIFT,
66 		.offset = vtophys(vcpu_info) & PAGE_MASK,
67 	};
68 	unsigned int cpu = XEN_VCPUID();
69 	int rc;
70 
71 	KASSERT(xen_domain(), ("%s(): invoked when not on Xen?", __func__));
72 
73 	_Static_assert(sizeof(struct vcpu_info) <= 64,
74 	    "struct vcpu_info is larger than supported limit of 64 bytes");
75 
76 	/*
77 	 * Set the vCPU info.
78 	 *
79 	 * NB: the vCPU info for some vCPUs can be fetched from the shared info
80 	 * page, but in order to make sure the mapping code is correct always
81 	 * attempt to map the vCPU info at a custom place.
82 	 */
83 	rc = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
84 	if (rc == 0)
85 		DPCPU_SET(vcpu_info, vcpu_info);
86 	else if (cpu < nitems(HYPERVISOR_shared_info->vcpu_info)) {
87 		static bool warned = false;
88 
89 		DPCPU_SET(vcpu_info, &HYPERVISOR_shared_info->vcpu_info[cpu]);
90 
91 		if (bootverbose && !warned) {
92 			warned = true;
93 			printf(
94 		"WARNING: Xen vCPU %u failed to setup vcpu_info rc = %d\n",
95 			    cpu, rc);
96 		}
97 	} else
98 		panic("Unable to register vCPU %u, rc=%d\n", cpu, rc);
99 }
100