xref: /titanic_44/usr/src/uts/i86pc/os/xpv_platform.c (revision a60349c89adffc0902b2353230891d8e7f2b24d9)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 
25 #include <sys/types.h>
26 #include <sys/archsystm.h>
27 #include <sys/machsystm.h>
28 #include <sys/sunndi.h>
29 #include <sys/sunddi.h>
30 #include <sys/ddi_subrdefs.h>
31 #include <sys/xpv_support.h>
32 #include <sys/xen_errno.h>
33 #include <sys/hypervisor.h>
34 #include <sys/gnttab.h>
35 #include <sys/xenbus_comms.h>
36 #include <sys/xenbus_impl.h>
37 #include <sys/sysmacros.h>
38 #include <sys/x86_archext.h>
39 #include <sys/mman.h>
40 #include <sys/stat.h>
41 #include <sys/conf.h>
42 #include <sys/devops.h>
43 #include <sys/pc_mmu.h>
44 #include <sys/cmn_err.h>
45 #include <sys/cpr.h>
46 #include <sys/ddi.h>
47 #include <vm/seg_kmem.h>
48 #include <vm/as.h>
49 #include <vm/hat_pte.h>
50 #include <vm/hat_i86.h>
51 
52 static int xen_hvm_inited;
53 
54 /*
55  * This structure is ordinarily constructed by Xen. In the HVM world, we
56  * manually fill in the few fields the PV drivers need.
57  */
58 static start_info_t __xen_info;
59 start_info_t *xen_info = NULL;
60 
61 static int xen_bits = -1;
62 static int xen_major = -1, xen_minor = -1;
63 
64 /*
65  * Feature bits; more bits will be added, like direct I/O, etc.
66  */
67 #define	XEN_HVM_HYPERCALLS	0x0001
68 #define	XEN_HVM_TLBFLUSH	0x0002
69 static uint64_t xen_hvm_features;
70 
71 /* Metadata page shared between domain and Xen */
72 shared_info_t *HYPERVISOR_shared_info = NULL;
73 pfn_t xen_shared_info_frame;
74 
75 /* Page containing code to issue hypercalls.  */
76 extern caddr_t hypercall_page;
77 extern caddr_t hypercall_shared_info_page;
78 
79 static int
80 hvm_get_param(int param_id, uint64_t *val)
81 {
82 	struct xen_hvm_param xhp;
83 
84 	xhp.domid = DOMID_SELF;
85 	xhp.index = param_id;
86 	if ((HYPERVISOR_hvm_op(HVMOP_get_param, &xhp) < 0))
87 		return (-1);
88 	*val = xhp.value;
89 	return (0);
90 }
91 
92 void
93 xen_hvm_init(void)
94 {
95 	struct cpuid_regs cp;
96 	uint32_t xen_signature[4], base;
97 	char *xen_str;
98 	struct xen_add_to_physmap xatp;
99 	xen_capabilities_info_t caps;
100 	pfn_t pfn;
101 	uint64_t msrval, val;
102 
103 	if (xen_hvm_inited != 0)
104 		return;
105 
106 	xen_hvm_inited = 1;
107 
108 	/*
109 	 * Xen's pseudo-cpuid function returns a string representing
110 	 * the Xen signature in %ebx, %ecx, and %edx.
111 	 * Loop over the base values, since it may be different if
112 	 * the hypervisor has hyper-v emulation switched on.
113 	 *
114 	 * %eax contains the maximum supported cpuid function.
115 	 */
116 	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
117 		cp.cp_eax = base;
118 		(void) __cpuid_insn(&cp);
119 		xen_signature[0] = cp.cp_ebx;
120 		xen_signature[1] = cp.cp_ecx;
121 		xen_signature[2] = cp.cp_edx;
122 		xen_signature[3] = 0;
123 		xen_str = (char *)xen_signature;
124 		if (strcmp("XenVMMXenVMM", xen_str)  == 0 &&
125 		    cp.cp_eax >= (base + 2))
126 			break;
127 	}
128 	if (base >= 0x40010000)
129 		return;
130 
131 	/*
132 	 * cpuid function at base + 1 returns the Xen version in %eax.  The
133 	 * top 16 bits are the major version, the bottom 16 are the minor
134 	 * version.
135 	 */
136 	cp.cp_eax = base + 1;
137 	(void) __cpuid_insn(&cp);
138 	xen_major = cp.cp_eax >> 16;
139 	xen_minor = cp.cp_eax & 0xffff;
140 
141 	/*
142 	 * Below version 3.1 we can't do anything special as a HVM domain;
143 	 * the PV drivers don't work, many hypercalls are not available,
144 	 * etc.
145 	 */
146 	if (xen_major < 3 || (xen_major == 3 && xen_minor < 1))
147 		return;
148 
149 	/*
150 	 * cpuid function at base + 2 returns information about the
151 	 * hypercall page.  %eax nominally contains the number of pages
152 	 * with hypercall code, but according to the Xen guys, "I'll
153 	 * guarantee that remains one forever more, so you can just
154 	 * allocate a single page and get quite upset if you ever see CPUID
155 	 * return more than one page."  %ebx contains an MSR we use to ask
156 	 * Xen to remap each page at a specific pfn.
157 	 */
158 	cp.cp_eax = base + 2;
159 	(void) __cpuid_insn(&cp);
160 
161 	/*
162 	 * Let Xen know where we want the hypercall page mapped.  We
163 	 * already have a page allocated in the .text section to simplify
164 	 * the wrapper code.
165 	 */
166 	pfn = va_to_pfn(&hypercall_page);
167 	msrval = mmu_ptob(pfn);
168 	wrmsr(cp.cp_ebx, msrval);
169 
170 	/* Fill in the xen_info data */
171 	xen_info = &__xen_info;
172 	(void) sprintf(xen_info->magic, "xen-%d.%d", xen_major, xen_minor);
173 
174 	if (hvm_get_param(HVM_PARAM_STORE_PFN, &val) < 0)
175 		return;
176 	/*
177 	 * The first hypercall worked, so mark hypercalls as working.
178 	 */
179 	xen_hvm_features |= XEN_HVM_HYPERCALLS;
180 
181 	xen_info->store_mfn = (mfn_t)val;
182 	if (hvm_get_param(HVM_PARAM_STORE_EVTCHN, &val) < 0)
183 		return;
184 	xen_info->store_evtchn = (mfn_t)val;
185 
186 	/* Figure out whether the hypervisor is 32-bit or 64-bit.  */
187 	if ((HYPERVISOR_xen_version(XENVER_capabilities, &caps) == 0)) {
188 		((char *)(caps))[sizeof (caps) - 1] = '\0';
189 		if (strstr(caps, "x86_64") != NULL)
190 			xen_bits = 64;
191 		else if (strstr(caps, "x86_32") != NULL)
192 			xen_bits = 32;
193 	}
194 
195 	if (xen_bits < 0)
196 		return;
197 #ifdef __amd64
198 	ASSERT(xen_bits == 64);
199 #endif
200 
201 	/*
202 	 * Allocate space for the shared_info page and tell Xen where it
203 	 * is.
204 	 */
205 	xen_shared_info_frame = va_to_pfn(&hypercall_shared_info_page);
206 	xatp.domid = DOMID_SELF;
207 	xatp.idx = 0;
208 	xatp.space = XENMAPSPACE_shared_info;
209 	xatp.gpfn = xen_shared_info_frame;
210 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp) != 0)
211 		return;
212 
213 	HYPERVISOR_shared_info = (void *)&hypercall_shared_info_page;
214 
215 	/*
216 	 * A working HVM tlb flush hypercall was introduced in Xen 3.3.
217 	 */
218 	if (xen_major > 3 || (xen_major == 3 && xen_minor >= 3))
219 		xen_hvm_features |= XEN_HVM_TLBFLUSH;
220 }
221 
222 /*
223  * Returns:
224  *          -1 if a feature is not available
225  *          1 if a boolean feature is available
226  *          > 0 if numeric feature is available
227  */
228 int
229 xpv_feature(int which)
230 {
231 	switch (which) {
232 	case XPVF_BITS:
233 		return (xen_bits);
234 	case XPVF_VERSION_MAJOR:
235 		return (xen_major);
236 	case XPVF_VERSION_MINOR:
237 		return (xen_minor);
238 	case XPVF_HYPERCALLS:
239 		if (xen_hvm_features & XEN_HVM_HYPERCALLS)
240 			return (1);
241 		break;
242 	case XPVF_SHARED_INFO:
243 		if (HYPERVISOR_shared_info != NULL)
244 			return (1);
245 		break;
246 	case XPVF_TLB_FLUSH:
247 		if (xen_hvm_features & XEN_HVM_TLBFLUSH)
248 			return (1);
249 		break;
250 	default:
251 		break;
252 	}
253 
254 	return (-1);
255 }
256