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
52static 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 */
58static start_info_t __xen_info;
59start_info_t *xen_info = NULL;
60
61static int xen_bits = -1;
62static 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
69static uint64_t xen_hvm_features;
70
71/* Metadata page shared between domain and Xen */
72shared_info_t *HYPERVISOR_shared_info = NULL;
73pfn_t xen_shared_info_frame;
74
75/* Page containing code to issue hypercalls.  */
76extern caddr_t hypercall_page;
77extern caddr_t hypercall_shared_info_page;
78
79static int
80hvm_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
92void
93xen_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 */
228int
229xpv_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