xref: /openbmc/linux/drivers/hv/hv.c (revision 6774def6)
1 /*
2  * Copyright (c) 2009, Microsoft Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Authors:
18  *   Haiyang Zhang <haiyangz@microsoft.com>
19  *   Hank Janssen  <hjanssen@microsoft.com>
20  *
21  */
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/kernel.h>
25 #include <linux/mm.h>
26 #include <linux/slab.h>
27 #include <linux/vmalloc.h>
28 #include <linux/hyperv.h>
29 #include <linux/version.h>
30 #include <linux/interrupt.h>
31 #include <asm/hyperv.h>
32 #include "hyperv_vmbus.h"
33 
34 /* The one and only */
35 struct hv_context hv_context = {
36 	.synic_initialized	= false,
37 	.hypercall_page		= NULL,
38 };
39 
40 /*
41  * query_hypervisor_info - Get version info of the windows hypervisor
42  */
43 unsigned int host_info_eax;
44 unsigned int host_info_ebx;
45 unsigned int host_info_ecx;
46 unsigned int host_info_edx;
47 
48 static int query_hypervisor_info(void)
49 {
50 	unsigned int eax;
51 	unsigned int ebx;
52 	unsigned int ecx;
53 	unsigned int edx;
54 	unsigned int max_leaf;
55 	unsigned int op;
56 
57 	/*
58 	* Its assumed that this is called after confirming that Viridian
59 	* is present. Query id and revision.
60 	*/
61 	eax = 0;
62 	ebx = 0;
63 	ecx = 0;
64 	edx = 0;
65 	op = HVCPUID_VENDOR_MAXFUNCTION;
66 	cpuid(op, &eax, &ebx, &ecx, &edx);
67 
68 	max_leaf = eax;
69 
70 	if (max_leaf >= HVCPUID_VERSION) {
71 		eax = 0;
72 		ebx = 0;
73 		ecx = 0;
74 		edx = 0;
75 		op = HVCPUID_VERSION;
76 		cpuid(op, &eax, &ebx, &ecx, &edx);
77 		host_info_eax = eax;
78 		host_info_ebx = ebx;
79 		host_info_ecx = ecx;
80 		host_info_edx = edx;
81 	}
82 	return max_leaf;
83 }
84 
85 /*
86  * do_hypercall- Invoke the specified hypercall
87  */
88 static u64 do_hypercall(u64 control, void *input, void *output)
89 {
90 #ifdef CONFIG_X86_64
91 	u64 hv_status = 0;
92 	u64 input_address = (input) ? virt_to_phys(input) : 0;
93 	u64 output_address = (output) ? virt_to_phys(output) : 0;
94 	void *hypercall_page = hv_context.hypercall_page;
95 
96 	__asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
97 	__asm__ __volatile__("call *%3" : "=a" (hv_status) :
98 			     "c" (control), "d" (input_address),
99 			     "m" (hypercall_page));
100 
101 	return hv_status;
102 
103 #else
104 
105 	u32 control_hi = control >> 32;
106 	u32 control_lo = control & 0xFFFFFFFF;
107 	u32 hv_status_hi = 1;
108 	u32 hv_status_lo = 1;
109 	u64 input_address = (input) ? virt_to_phys(input) : 0;
110 	u32 input_address_hi = input_address >> 32;
111 	u32 input_address_lo = input_address & 0xFFFFFFFF;
112 	u64 output_address = (output) ? virt_to_phys(output) : 0;
113 	u32 output_address_hi = output_address >> 32;
114 	u32 output_address_lo = output_address & 0xFFFFFFFF;
115 	void *hypercall_page = hv_context.hypercall_page;
116 
117 	__asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
118 			      "=a"(hv_status_lo) : "d" (control_hi),
119 			      "a" (control_lo), "b" (input_address_hi),
120 			      "c" (input_address_lo), "D"(output_address_hi),
121 			      "S"(output_address_lo), "m" (hypercall_page));
122 
123 	return hv_status_lo | ((u64)hv_status_hi << 32);
124 #endif /* !x86_64 */
125 }
126 
127 /*
128  * hv_init - Main initialization routine.
129  *
130  * This routine must be called before any other routines in here are called
131  */
132 int hv_init(void)
133 {
134 	int max_leaf;
135 	union hv_x64_msr_hypercall_contents hypercall_msr;
136 	void *virtaddr = NULL;
137 
138 	memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
139 	memset(hv_context.synic_message_page, 0,
140 	       sizeof(void *) * NR_CPUS);
141 	memset(hv_context.post_msg_page, 0,
142 	       sizeof(void *) * NR_CPUS);
143 	memset(hv_context.vp_index, 0,
144 	       sizeof(int) * NR_CPUS);
145 	memset(hv_context.event_dpc, 0,
146 	       sizeof(void *) * NR_CPUS);
147 
148 	max_leaf = query_hypervisor_info();
149 
150 	/*
151 	 * Write our OS ID.
152 	 */
153 	hv_context.guestid = generate_guest_id(0, LINUX_VERSION_CODE, 0);
154 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
155 
156 	/* See if the hypercall page is already set */
157 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
158 
159 	virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
160 
161 	if (!virtaddr)
162 		goto cleanup;
163 
164 	hypercall_msr.enable = 1;
165 
166 	hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
167 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
168 
169 	/* Confirm that hypercall page did get setup. */
170 	hypercall_msr.as_uint64 = 0;
171 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
172 
173 	if (!hypercall_msr.enable)
174 		goto cleanup;
175 
176 	hv_context.hypercall_page = virtaddr;
177 
178 	return 0;
179 
180 cleanup:
181 	if (virtaddr) {
182 		if (hypercall_msr.enable) {
183 			hypercall_msr.as_uint64 = 0;
184 			wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
185 		}
186 
187 		vfree(virtaddr);
188 	}
189 
190 	return -ENOTSUPP;
191 }
192 
193 /*
194  * hv_cleanup - Cleanup routine.
195  *
196  * This routine is called normally during driver unloading or exiting.
197  */
198 void hv_cleanup(void)
199 {
200 	union hv_x64_msr_hypercall_contents hypercall_msr;
201 
202 	/* Reset our OS id */
203 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
204 
205 	if (hv_context.hypercall_page) {
206 		hypercall_msr.as_uint64 = 0;
207 		wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
208 		vfree(hv_context.hypercall_page);
209 		hv_context.hypercall_page = NULL;
210 	}
211 }
212 
213 /*
214  * hv_post_message - Post a message using the hypervisor message IPC.
215  *
216  * This involves a hypercall.
217  */
218 int hv_post_message(union hv_connection_id connection_id,
219 		  enum hv_message_type message_type,
220 		  void *payload, size_t payload_size)
221 {
222 
223 	struct hv_input_post_message *aligned_msg;
224 	u16 status;
225 
226 	if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
227 		return -EMSGSIZE;
228 
229 	aligned_msg = (struct hv_input_post_message *)
230 			hv_context.post_msg_page[get_cpu()];
231 
232 	aligned_msg->connectionid = connection_id;
233 	aligned_msg->reserved = 0;
234 	aligned_msg->message_type = message_type;
235 	aligned_msg->payload_size = payload_size;
236 	memcpy((void *)aligned_msg->payload, payload, payload_size);
237 
238 	status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
239 		& 0xFFFF;
240 
241 	put_cpu();
242 	return status;
243 }
244 
245 
246 /*
247  * hv_signal_event -
248  * Signal an event on the specified connection using the hypervisor event IPC.
249  *
250  * This involves a hypercall.
251  */
252 u16 hv_signal_event(void *con_id)
253 {
254 	u16 status;
255 
256 	status = (do_hypercall(HVCALL_SIGNAL_EVENT, con_id, NULL) & 0xFFFF);
257 
258 	return status;
259 }
260 
261 
262 int hv_synic_alloc(void)
263 {
264 	size_t size = sizeof(struct tasklet_struct);
265 	int cpu;
266 
267 	for_each_online_cpu(cpu) {
268 		hv_context.event_dpc[cpu] = kmalloc(size, GFP_ATOMIC);
269 		if (hv_context.event_dpc[cpu] == NULL) {
270 			pr_err("Unable to allocate event dpc\n");
271 			goto err;
272 		}
273 		tasklet_init(hv_context.event_dpc[cpu], vmbus_on_event, cpu);
274 
275 		hv_context.synic_message_page[cpu] =
276 			(void *)get_zeroed_page(GFP_ATOMIC);
277 
278 		if (hv_context.synic_message_page[cpu] == NULL) {
279 			pr_err("Unable to allocate SYNIC message page\n");
280 			goto err;
281 		}
282 
283 		hv_context.synic_event_page[cpu] =
284 			(void *)get_zeroed_page(GFP_ATOMIC);
285 
286 		if (hv_context.synic_event_page[cpu] == NULL) {
287 			pr_err("Unable to allocate SYNIC event page\n");
288 			goto err;
289 		}
290 
291 		hv_context.post_msg_page[cpu] =
292 			(void *)get_zeroed_page(GFP_ATOMIC);
293 
294 		if (hv_context.post_msg_page[cpu] == NULL) {
295 			pr_err("Unable to allocate post msg page\n");
296 			goto err;
297 		}
298 	}
299 
300 	return 0;
301 err:
302 	return -ENOMEM;
303 }
304 
305 static void hv_synic_free_cpu(int cpu)
306 {
307 	kfree(hv_context.event_dpc[cpu]);
308 	if (hv_context.synic_event_page[cpu])
309 		free_page((unsigned long)hv_context.synic_event_page[cpu]);
310 	if (hv_context.synic_message_page[cpu])
311 		free_page((unsigned long)hv_context.synic_message_page[cpu]);
312 	if (hv_context.post_msg_page[cpu])
313 		free_page((unsigned long)hv_context.post_msg_page[cpu]);
314 }
315 
316 void hv_synic_free(void)
317 {
318 	int cpu;
319 
320 	for_each_online_cpu(cpu)
321 		hv_synic_free_cpu(cpu);
322 }
323 
324 /*
325  * hv_synic_init - Initialize the Synthethic Interrupt Controller.
326  *
327  * If it is already initialized by another entity (ie x2v shim), we need to
328  * retrieve the initialized message and event pages.  Otherwise, we create and
329  * initialize the message and event pages.
330  */
331 void hv_synic_init(void *arg)
332 {
333 	u64 version;
334 	union hv_synic_simp simp;
335 	union hv_synic_siefp siefp;
336 	union hv_synic_sint shared_sint;
337 	union hv_synic_scontrol sctrl;
338 	u64 vp_index;
339 
340 	int cpu = smp_processor_id();
341 
342 	if (!hv_context.hypercall_page)
343 		return;
344 
345 	/* Check the version */
346 	rdmsrl(HV_X64_MSR_SVERSION, version);
347 
348 	/* Setup the Synic's message page */
349 	rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
350 	simp.simp_enabled = 1;
351 	simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
352 		>> PAGE_SHIFT;
353 
354 	wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
355 
356 	/* Setup the Synic's event page */
357 	rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
358 	siefp.siefp_enabled = 1;
359 	siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
360 		>> PAGE_SHIFT;
361 
362 	wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
363 
364 	/* Setup the shared SINT. */
365 	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
366 
367 	shared_sint.as_uint64 = 0;
368 	shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
369 	shared_sint.masked = false;
370 	shared_sint.auto_eoi = true;
371 
372 	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
373 
374 	/* Enable the global synic bit */
375 	rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
376 	sctrl.enable = 1;
377 
378 	wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
379 
380 	hv_context.synic_initialized = true;
381 
382 	/*
383 	 * Setup the mapping between Hyper-V's notion
384 	 * of cpuid and Linux' notion of cpuid.
385 	 * This array will be indexed using Linux cpuid.
386 	 */
387 	rdmsrl(HV_X64_MSR_VP_INDEX, vp_index);
388 	hv_context.vp_index[cpu] = (u32)vp_index;
389 
390 	INIT_LIST_HEAD(&hv_context.percpu_list[cpu]);
391 	return;
392 }
393 
394 /*
395  * hv_synic_cleanup - Cleanup routine for hv_synic_init().
396  */
397 void hv_synic_cleanup(void *arg)
398 {
399 	union hv_synic_sint shared_sint;
400 	union hv_synic_simp simp;
401 	union hv_synic_siefp siefp;
402 	int cpu = smp_processor_id();
403 
404 	if (!hv_context.synic_initialized)
405 		return;
406 
407 	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
408 
409 	shared_sint.masked = 1;
410 
411 	/* Need to correctly cleanup in the case of SMP!!! */
412 	/* Disable the interrupt */
413 	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
414 
415 	rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
416 	simp.simp_enabled = 0;
417 	simp.base_simp_gpa = 0;
418 
419 	wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
420 
421 	rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
422 	siefp.siefp_enabled = 0;
423 	siefp.base_siefp_gpa = 0;
424 
425 	wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
426 
427 	free_page((unsigned long)hv_context.synic_message_page[cpu]);
428 	free_page((unsigned long)hv_context.synic_event_page[cpu]);
429 }
430