Staging: hv: netvsc: Fix a dereferencing issue
[linux-2.6.git] / drivers / hv / hv.c
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
30 #include "hyperv_vmbus.h"
31
32 /* The one and only */
33 struct hv_context hv_context = {
34         .synic_initialized      = false,
35         .hypercall_page         = NULL,
36         .signal_event_param     = NULL,
37         .signal_event_buffer    = NULL,
38 };
39
40 /*
41  * query_hypervisor_presence
42  * - Query the cpuid for presence of windows hypervisor
43  */
44 static int query_hypervisor_presence(void)
45 {
46         unsigned int eax;
47         unsigned int ebx;
48         unsigned int ecx;
49         unsigned int edx;
50         unsigned int op;
51
52         eax = 0;
53         ebx = 0;
54         ecx = 0;
55         edx = 0;
56         op = HVCPUID_VERSION_FEATURES;
57         cpuid(op, &eax, &ebx, &ecx, &edx);
58
59         return ecx & HV_PRESENT_BIT;
60 }
61
62 /*
63  * query_hypervisor_info - Get version info of the windows hypervisor
64  */
65 static int query_hypervisor_info(void)
66 {
67         unsigned int eax;
68         unsigned int ebx;
69         unsigned int ecx;
70         unsigned int edx;
71         unsigned int max_leaf;
72         unsigned int op;
73
74         /*
75         * Its assumed that this is called after confirming that Viridian
76         * is present. Query id and revision.
77         */
78         eax = 0;
79         ebx = 0;
80         ecx = 0;
81         edx = 0;
82         op = HVCPUID_VENDOR_MAXFUNCTION;
83         cpuid(op, &eax, &ebx, &ecx, &edx);
84
85         max_leaf = eax;
86
87         if (max_leaf >= HVCPUID_VERSION) {
88                 eax = 0;
89                 ebx = 0;
90                 ecx = 0;
91                 edx = 0;
92                 op = HVCPUID_VERSION;
93                 cpuid(op, &eax, &ebx, &ecx, &edx);
94                 pr_info("Hyper-V Host OS Build:%d-%d.%d-%d-%d.%d\n",
95                             eax,
96                             ebx >> 16,
97                             ebx & 0xFFFF,
98                             ecx,
99                             edx >> 24,
100                             edx & 0xFFFFFF);
101         }
102         return max_leaf;
103 }
104
105 /*
106  * do_hypercall- Invoke the specified hypercall
107  */
108 static u64 do_hypercall(u64 control, void *input, void *output)
109 {
110 #ifdef CONFIG_X86_64
111         u64 hv_status = 0;
112         u64 input_address = (input) ? virt_to_phys(input) : 0;
113         u64 output_address = (output) ? virt_to_phys(output) : 0;
114         void *hypercall_page = hv_context.hypercall_page;
115
116         __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
117         __asm__ __volatile__("call *%3" : "=a" (hv_status) :
118                              "c" (control), "d" (input_address),
119                              "m" (hypercall_page));
120
121         return hv_status;
122
123 #else
124
125         u32 control_hi = control >> 32;
126         u32 control_lo = control & 0xFFFFFFFF;
127         u32 hv_status_hi = 1;
128         u32 hv_status_lo = 1;
129         u64 input_address = (input) ? virt_to_phys(input) : 0;
130         u32 input_address_hi = input_address >> 32;
131         u32 input_address_lo = input_address & 0xFFFFFFFF;
132         u64 output_address = (output) ? virt_to_phys(output) : 0;
133         u32 output_address_hi = output_address >> 32;
134         u32 output_address_lo = output_address & 0xFFFFFFFF;
135         void *hypercall_page = hv_context.hypercall_page;
136
137         __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
138                               "=a"(hv_status_lo) : "d" (control_hi),
139                               "a" (control_lo), "b" (input_address_hi),
140                               "c" (input_address_lo), "D"(output_address_hi),
141                               "S"(output_address_lo), "m" (hypercall_page));
142
143         return hv_status_lo | ((u64)hv_status_hi << 32);
144 #endif /* !x86_64 */
145 }
146
147 /*
148  * hv_init - Main initialization routine.
149  *
150  * This routine must be called before any other routines in here are called
151  */
152 int hv_init(void)
153 {
154         int max_leaf;
155         union hv_x64_msr_hypercall_contents hypercall_msr;
156         void *virtaddr = NULL;
157
158         memset(hv_context.synic_event_page, 0, sizeof(void *) * MAX_NUM_CPUS);
159         memset(hv_context.synic_message_page, 0,
160                sizeof(void *) * MAX_NUM_CPUS);
161
162         if (!query_hypervisor_presence())
163                 goto cleanup;
164
165         max_leaf = query_hypervisor_info();
166
167         rdmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
168
169         if (hv_context.guestid != 0)
170                 goto cleanup;
171
172         /* Write our OS info */
173         wrmsrl(HV_X64_MSR_GUEST_OS_ID, HV_LINUX_GUEST_ID);
174         hv_context.guestid = HV_LINUX_GUEST_ID;
175
176         /* See if the hypercall page is already set */
177         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
178
179         virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
180
181         if (!virtaddr)
182                 goto cleanup;
183
184         hypercall_msr.enable = 1;
185
186         hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
187         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
188
189         /* Confirm that hypercall page did get setup. */
190         hypercall_msr.as_uint64 = 0;
191         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
192
193         if (!hypercall_msr.enable)
194                 goto cleanup;
195
196         hv_context.hypercall_page = virtaddr;
197
198         /* Setup the global signal event param for the signal event hypercall */
199         hv_context.signal_event_buffer =
200                         kmalloc(sizeof(struct hv_input_signal_event_buffer),
201                                 GFP_KERNEL);
202         if (!hv_context.signal_event_buffer)
203                 goto cleanup;
204
205         hv_context.signal_event_param =
206                 (struct hv_input_signal_event *)
207                         (ALIGN((unsigned long)
208                                   hv_context.signal_event_buffer,
209                                   HV_HYPERCALL_PARAM_ALIGN));
210         hv_context.signal_event_param->connectionid.asu32 = 0;
211         hv_context.signal_event_param->connectionid.u.id =
212                                                 VMBUS_EVENT_CONNECTION_ID;
213         hv_context.signal_event_param->flag_number = 0;
214         hv_context.signal_event_param->rsvdz = 0;
215
216         return 0;
217
218 cleanup:
219         if (virtaddr) {
220                 if (hypercall_msr.enable) {
221                         hypercall_msr.as_uint64 = 0;
222                         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
223                 }
224
225                 vfree(virtaddr);
226         }
227
228         return -ENOTSUPP;
229 }
230
231 /*
232  * hv_cleanup - Cleanup routine.
233  *
234  * This routine is called normally during driver unloading or exiting.
235  */
236 void hv_cleanup(void)
237 {
238         union hv_x64_msr_hypercall_contents hypercall_msr;
239
240         kfree(hv_context.signal_event_buffer);
241         hv_context.signal_event_buffer = NULL;
242         hv_context.signal_event_param = NULL;
243
244         if (hv_context.hypercall_page) {
245                 hypercall_msr.as_uint64 = 0;
246                 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
247                 vfree(hv_context.hypercall_page);
248                 hv_context.hypercall_page = NULL;
249         }
250 }
251
252 /*
253  * hv_post_message - Post a message using the hypervisor message IPC.
254  *
255  * This involves a hypercall.
256  */
257 u16 hv_post_message(union hv_connection_id connection_id,
258                   enum hv_message_type message_type,
259                   void *payload, size_t payload_size)
260 {
261         struct aligned_input {
262                 u64 alignment8;
263                 struct hv_input_post_message msg;
264         };
265
266         struct hv_input_post_message *aligned_msg;
267         u16 status;
268         unsigned long addr;
269
270         if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
271                 return -EMSGSIZE;
272
273         addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC);
274         if (!addr)
275                 return -ENOMEM;
276
277         aligned_msg = (struct hv_input_post_message *)
278                         (ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN));
279
280         aligned_msg->connectionid = connection_id;
281         aligned_msg->message_type = message_type;
282         aligned_msg->payload_size = payload_size;
283         memcpy((void *)aligned_msg->payload, payload, payload_size);
284
285         status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
286                 & 0xFFFF;
287
288         kfree((void *)addr);
289
290         return status;
291 }
292
293
294 /*
295  * hv_signal_event -
296  * Signal an event on the specified connection using the hypervisor event IPC.
297  *
298  * This involves a hypercall.
299  */
300 u16 hv_signal_event(void)
301 {
302         u16 status;
303
304         status = do_hypercall(HVCALL_SIGNAL_EVENT,
305                                hv_context.signal_event_param,
306                                NULL) & 0xFFFF;
307         return status;
308 }
309
310 /*
311  * hv_synic_init - Initialize the Synthethic Interrupt Controller.
312  *
313  * If it is already initialized by another entity (ie x2v shim), we need to
314  * retrieve the initialized message and event pages.  Otherwise, we create and
315  * initialize the message and event pages.
316  */
317 void hv_synic_init(void *irqarg)
318 {
319         u64 version;
320         union hv_synic_simp simp;
321         union hv_synic_siefp siefp;
322         union hv_synic_sint shared_sint;
323         union hv_synic_scontrol sctrl;
324
325         u32 irq_vector = *((u32 *)(irqarg));
326         int cpu = smp_processor_id();
327
328         if (!hv_context.hypercall_page)
329                 return;
330
331         /* Check the version */
332         rdmsrl(HV_X64_MSR_SVERSION, version);
333
334         hv_context.synic_message_page[cpu] =
335                 (void *)get_zeroed_page(GFP_ATOMIC);
336
337         if (hv_context.synic_message_page[cpu] == NULL) {
338                 pr_err("Unable to allocate SYNIC message page\n");
339                 goto cleanup;
340         }
341
342         hv_context.synic_event_page[cpu] =
343                 (void *)get_zeroed_page(GFP_ATOMIC);
344
345         if (hv_context.synic_event_page[cpu] == NULL) {
346                 pr_err("Unable to allocate SYNIC event page\n");
347                 goto cleanup;
348         }
349
350         /* Setup the Synic's message page */
351         rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
352         simp.simp_enabled = 1;
353         simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
354                 >> PAGE_SHIFT;
355
356         wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
357
358         /* Setup the Synic's event page */
359         rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
360         siefp.siefp_enabled = 1;
361         siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
362                 >> PAGE_SHIFT;
363
364         wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
365
366         /* Setup the shared SINT. */
367         rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
368
369         shared_sint.as_uint64 = 0;
370         shared_sint.vector = irq_vector; /* HV_SHARED_SINT_IDT_VECTOR + 0x20; */
371         shared_sint.masked = false;
372         shared_sint.auto_eoi = false;
373
374         wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
375
376         /* Enable the global synic bit */
377         rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
378         sctrl.enable = 1;
379
380         wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
381
382         hv_context.synic_initialized = true;
383         return;
384
385 cleanup:
386         if (hv_context.synic_event_page[cpu])
387                 free_page((unsigned long)hv_context.synic_event_page[cpu]);
388
389         if (hv_context.synic_message_page[cpu])
390                 free_page((unsigned long)hv_context.synic_message_page[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 }