xref: /openbmc/linux/drivers/hv/hv.c (revision f7018c21)
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.vp_index, 0,
142 	       sizeof(int) * NR_CPUS);
143 	memset(hv_context.event_dpc, 0,
144 	       sizeof(void *) * NR_CPUS);
145 
146 	max_leaf = query_hypervisor_info();
147 
148 	/*
149 	 * Write our OS ID.
150 	 */
151 	hv_context.guestid = generate_guest_id(0, LINUX_VERSION_CODE, 0);
152 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
153 
154 	/* See if the hypercall page is already set */
155 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
156 
157 	virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
158 
159 	if (!virtaddr)
160 		goto cleanup;
161 
162 	hypercall_msr.enable = 1;
163 
164 	hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
165 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
166 
167 	/* Confirm that hypercall page did get setup. */
168 	hypercall_msr.as_uint64 = 0;
169 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
170 
171 	if (!hypercall_msr.enable)
172 		goto cleanup;
173 
174 	hv_context.hypercall_page = virtaddr;
175 
176 	return 0;
177 
178 cleanup:
179 	if (virtaddr) {
180 		if (hypercall_msr.enable) {
181 			hypercall_msr.as_uint64 = 0;
182 			wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
183 		}
184 
185 		vfree(virtaddr);
186 	}
187 
188 	return -ENOTSUPP;
189 }
190 
191 /*
192  * hv_cleanup - Cleanup routine.
193  *
194  * This routine is called normally during driver unloading or exiting.
195  */
196 void hv_cleanup(void)
197 {
198 	union hv_x64_msr_hypercall_contents hypercall_msr;
199 
200 	/* Reset our OS id */
201 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
202 
203 	if (hv_context.hypercall_page) {
204 		hypercall_msr.as_uint64 = 0;
205 		wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
206 		vfree(hv_context.hypercall_page);
207 		hv_context.hypercall_page = NULL;
208 	}
209 }
210 
211 /*
212  * hv_post_message - Post a message using the hypervisor message IPC.
213  *
214  * This involves a hypercall.
215  */
216 int hv_post_message(union hv_connection_id connection_id,
217 		  enum hv_message_type message_type,
218 		  void *payload, size_t payload_size)
219 {
220 	struct aligned_input {
221 		u64 alignment8;
222 		struct hv_input_post_message msg;
223 	};
224 
225 	struct hv_input_post_message *aligned_msg;
226 	u16 status;
227 	unsigned long addr;
228 
229 	if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
230 		return -EMSGSIZE;
231 
232 	addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC);
233 	if (!addr)
234 		return -ENOMEM;
235 
236 	aligned_msg = (struct hv_input_post_message *)
237 			(ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN));
238 
239 	aligned_msg->connectionid = connection_id;
240 	aligned_msg->message_type = message_type;
241 	aligned_msg->payload_size = payload_size;
242 	memcpy((void *)aligned_msg->payload, payload, payload_size);
243 
244 	status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
245 		& 0xFFFF;
246 
247 	kfree((void *)addr);
248 
249 	return status;
250 }
251 
252 
253 /*
254  * hv_signal_event -
255  * Signal an event on the specified connection using the hypervisor event IPC.
256  *
257  * This involves a hypercall.
258  */
259 u16 hv_signal_event(void *con_id)
260 {
261 	u16 status;
262 
263 	status = (do_hypercall(HVCALL_SIGNAL_EVENT, con_id, NULL) & 0xFFFF);
264 
265 	return status;
266 }
267 
268 
269 int hv_synic_alloc(void)
270 {
271 	size_t size = sizeof(struct tasklet_struct);
272 	int cpu;
273 
274 	for_each_online_cpu(cpu) {
275 		hv_context.event_dpc[cpu] = kmalloc(size, GFP_ATOMIC);
276 		if (hv_context.event_dpc[cpu] == NULL) {
277 			pr_err("Unable to allocate event dpc\n");
278 			goto err;
279 		}
280 		tasklet_init(hv_context.event_dpc[cpu], vmbus_on_event, cpu);
281 
282 		hv_context.synic_message_page[cpu] =
283 			(void *)get_zeroed_page(GFP_ATOMIC);
284 
285 		if (hv_context.synic_message_page[cpu] == NULL) {
286 			pr_err("Unable to allocate SYNIC message page\n");
287 			goto err;
288 		}
289 
290 		hv_context.synic_event_page[cpu] =
291 			(void *)get_zeroed_page(GFP_ATOMIC);
292 
293 		if (hv_context.synic_event_page[cpu] == NULL) {
294 			pr_err("Unable to allocate SYNIC event page\n");
295 			goto err;
296 		}
297 	}
298 
299 	return 0;
300 err:
301 	return -ENOMEM;
302 }
303 
304 static void hv_synic_free_cpu(int cpu)
305 {
306 	kfree(hv_context.event_dpc[cpu]);
307 	if (hv_context.synic_event_page[cpu])
308 		free_page((unsigned long)hv_context.synic_event_page[cpu]);
309 	if (hv_context.synic_message_page[cpu])
310 		free_page((unsigned long)hv_context.synic_message_page[cpu]);
311 }
312 
313 void hv_synic_free(void)
314 {
315 	int cpu;
316 
317 	for_each_online_cpu(cpu)
318 		hv_synic_free_cpu(cpu);
319 }
320 
321 /*
322  * hv_synic_init - Initialize the Synthethic Interrupt Controller.
323  *
324  * If it is already initialized by another entity (ie x2v shim), we need to
325  * retrieve the initialized message and event pages.  Otherwise, we create and
326  * initialize the message and event pages.
327  */
328 void hv_synic_init(void *arg)
329 {
330 	u64 version;
331 	union hv_synic_simp simp;
332 	union hv_synic_siefp siefp;
333 	union hv_synic_sint shared_sint;
334 	union hv_synic_scontrol sctrl;
335 	u64 vp_index;
336 
337 	int cpu = smp_processor_id();
338 
339 	if (!hv_context.hypercall_page)
340 		return;
341 
342 	/* Check the version */
343 	rdmsrl(HV_X64_MSR_SVERSION, version);
344 
345 	/* Setup the Synic's message page */
346 	rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
347 	simp.simp_enabled = 1;
348 	simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
349 		>> PAGE_SHIFT;
350 
351 	wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
352 
353 	/* Setup the Synic's event page */
354 	rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
355 	siefp.siefp_enabled = 1;
356 	siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
357 		>> PAGE_SHIFT;
358 
359 	wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
360 
361 	/* Setup the shared SINT. */
362 	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
363 
364 	shared_sint.as_uint64 = 0;
365 	shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
366 	shared_sint.masked = false;
367 	shared_sint.auto_eoi = true;
368 
369 	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
370 
371 	/* Enable the global synic bit */
372 	rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
373 	sctrl.enable = 1;
374 
375 	wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
376 
377 	hv_context.synic_initialized = true;
378 
379 	/*
380 	 * Setup the mapping between Hyper-V's notion
381 	 * of cpuid and Linux' notion of cpuid.
382 	 * This array will be indexed using Linux cpuid.
383 	 */
384 	rdmsrl(HV_X64_MSR_VP_INDEX, vp_index);
385 	hv_context.vp_index[cpu] = (u32)vp_index;
386 	return;
387 }
388 
389 /*
390  * hv_synic_cleanup - Cleanup routine for hv_synic_init().
391  */
392 void hv_synic_cleanup(void *arg)
393 {
394 	union hv_synic_sint shared_sint;
395 	union hv_synic_simp simp;
396 	union hv_synic_siefp siefp;
397 	int cpu = smp_processor_id();
398 
399 	if (!hv_context.synic_initialized)
400 		return;
401 
402 	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
403 
404 	shared_sint.masked = 1;
405 
406 	/* Need to correctly cleanup in the case of SMP!!! */
407 	/* Disable the interrupt */
408 	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
409 
410 	rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
411 	simp.simp_enabled = 0;
412 	simp.base_simp_gpa = 0;
413 
414 	wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
415 
416 	rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
417 	siefp.siefp_enabled = 0;
418 	siefp.base_siefp_gpa = 0;
419 
420 	wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
421 
422 	free_page((unsigned long)hv_context.synic_message_page[cpu]);
423 	free_page((unsigned long)hv_context.synic_event_page[cpu]);
424 }
425