drivers: hv: Turn off write permission on the hypercall page
[pandora-kernel.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 #include <asm/hyperv.h>
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         memset(hv_context.post_msg_page, 0,
162                sizeof(void *) * MAX_NUM_CPUS);
163
164         if (!query_hypervisor_presence())
165                 goto cleanup;
166
167         max_leaf = query_hypervisor_info();
168
169         rdmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
170
171         if (hv_context.guestid != 0)
172                 goto cleanup;
173
174         /* Write our OS info */
175         wrmsrl(HV_X64_MSR_GUEST_OS_ID, HV_LINUX_GUEST_ID);
176         hv_context.guestid = HV_LINUX_GUEST_ID;
177
178         /* See if the hypercall page is already set */
179         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
180
181         virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
182
183         if (!virtaddr)
184                 goto cleanup;
185
186         hypercall_msr.enable = 1;
187
188         hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
189         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
190
191         /* Confirm that hypercall page did get setup. */
192         hypercall_msr.as_uint64 = 0;
193         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
194
195         if (!hypercall_msr.enable)
196                 goto cleanup;
197
198         hv_context.hypercall_page = virtaddr;
199
200         /* Setup the global signal event param for the signal event hypercall */
201         hv_context.signal_event_buffer =
202                         kmalloc(sizeof(struct hv_input_signal_event_buffer),
203                                 GFP_KERNEL);
204         if (!hv_context.signal_event_buffer)
205                 goto cleanup;
206
207         hv_context.signal_event_param =
208                 (struct hv_input_signal_event *)
209                         (ALIGN((unsigned long)
210                                   hv_context.signal_event_buffer,
211                                   HV_HYPERCALL_PARAM_ALIGN));
212         hv_context.signal_event_param->connectionid.asu32 = 0;
213         hv_context.signal_event_param->connectionid.u.id =
214                                                 VMBUS_EVENT_CONNECTION_ID;
215         hv_context.signal_event_param->flag_number = 0;
216         hv_context.signal_event_param->rsvdz = 0;
217
218         return 0;
219
220 cleanup:
221         if (virtaddr) {
222                 if (hypercall_msr.enable) {
223                         hypercall_msr.as_uint64 = 0;
224                         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
225                 }
226
227                 vfree(virtaddr);
228         }
229
230         return -ENOTSUPP;
231 }
232
233 /*
234  * hv_cleanup - Cleanup routine.
235  *
236  * This routine is called normally during driver unloading or exiting.
237  */
238 void hv_cleanup(void)
239 {
240         union hv_x64_msr_hypercall_contents hypercall_msr;
241
242         kfree(hv_context.signal_event_buffer);
243         hv_context.signal_event_buffer = NULL;
244         hv_context.signal_event_param = NULL;
245
246         if (hv_context.hypercall_page) {
247                 hypercall_msr.as_uint64 = 0;
248                 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
249                 vfree(hv_context.hypercall_page);
250                 hv_context.hypercall_page = NULL;
251         }
252 }
253
254 /*
255  * hv_post_message - Post a message using the hypervisor message IPC.
256  *
257  * This involves a hypercall.
258  */
259 u16 hv_post_message(union hv_connection_id connection_id,
260                   enum hv_message_type message_type,
261                   void *payload, size_t payload_size)
262 {
263
264         struct hv_input_post_message *aligned_msg;
265         u16 status;
266
267         if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
268                 return -EMSGSIZE;
269
270         aligned_msg = (struct hv_input_post_message *)
271                         hv_context.post_msg_page[get_cpu()];
272
273         aligned_msg->connectionid = connection_id;
274         aligned_msg->reserved = 0;
275         aligned_msg->message_type = message_type;
276         aligned_msg->payload_size = payload_size;
277         memcpy((void *)aligned_msg->payload, payload, payload_size);
278
279         status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
280                 & 0xFFFF;
281
282         put_cpu();
283         return status;
284 }
285
286
287 /*
288  * hv_signal_event -
289  * Signal an event on the specified connection using the hypervisor event IPC.
290  *
291  * This involves a hypercall.
292  */
293 u16 hv_signal_event(void)
294 {
295         u16 status;
296
297         status = do_hypercall(HVCALL_SIGNAL_EVENT,
298                                hv_context.signal_event_param,
299                                NULL) & 0xFFFF;
300         return status;
301 }
302
303 /*
304  * hv_synic_init - Initialize the Synthethic Interrupt Controller.
305  *
306  * If it is already initialized by another entity (ie x2v shim), we need to
307  * retrieve the initialized message and event pages.  Otherwise, we create and
308  * initialize the message and event pages.
309  */
310 void hv_synic_init(void *irqarg)
311 {
312         u64 version;
313         union hv_synic_simp simp;
314         union hv_synic_siefp siefp;
315         union hv_synic_sint shared_sint;
316         union hv_synic_scontrol sctrl;
317
318         u32 irq_vector = *((u32 *)(irqarg));
319         int cpu = smp_processor_id();
320
321         if (!hv_context.hypercall_page)
322                 return;
323
324         /* Check the version */
325         rdmsrl(HV_X64_MSR_SVERSION, version);
326
327         hv_context.synic_message_page[cpu] =
328                 (void *)get_zeroed_page(GFP_ATOMIC);
329
330         if (hv_context.synic_message_page[cpu] == NULL) {
331                 pr_err("Unable to allocate SYNIC message page\n");
332                 goto cleanup;
333         }
334
335         hv_context.synic_event_page[cpu] =
336                 (void *)get_zeroed_page(GFP_ATOMIC);
337
338         if (hv_context.synic_event_page[cpu] == NULL) {
339                 pr_err("Unable to allocate SYNIC event page\n");
340                 goto cleanup;
341         }
342
343         hv_context.post_msg_page[cpu] =
344                 (void *)get_zeroed_page(GFP_ATOMIC);
345
346         if (hv_context.post_msg_page[cpu] == NULL) {
347                 pr_err("Unable to allocate post msg page\n");
348                 goto cleanup;
349         }
350
351         /* Setup the Synic's message page */
352         rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
353         simp.simp_enabled = 1;
354         simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
355                 >> PAGE_SHIFT;
356
357         wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
358
359         /* Setup the Synic's event page */
360         rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
361         siefp.siefp_enabled = 1;
362         siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
363                 >> PAGE_SHIFT;
364
365         wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
366
367         /* Setup the shared SINT. */
368         rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
369
370         shared_sint.as_uint64 = 0;
371         shared_sint.vector = irq_vector; /* HV_SHARED_SINT_IDT_VECTOR + 0x20; */
372         shared_sint.masked = false;
373         shared_sint.auto_eoi = false;
374
375         wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
376
377         /* Enable the global synic bit */
378         rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
379         sctrl.enable = 1;
380
381         wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
382
383         hv_context.synic_initialized = true;
384         return;
385
386 cleanup:
387         if (hv_context.synic_event_page[cpu])
388                 free_page((unsigned long)hv_context.synic_event_page[cpu]);
389
390         if (hv_context.synic_message_page[cpu])
391                 free_page((unsigned long)hv_context.synic_message_page[cpu]);
392         if (hv_context.post_msg_page[cpu])
393                 free_page((unsigned long)hv_context.post_msg_page[cpu]);
394         return;
395 }
396
397 /*
398  * hv_synic_cleanup - Cleanup routine for hv_synic_init().
399  */
400 void hv_synic_cleanup(void *arg)
401 {
402         union hv_synic_sint shared_sint;
403         union hv_synic_simp simp;
404         union hv_synic_siefp siefp;
405         int cpu = smp_processor_id();
406
407         if (!hv_context.synic_initialized)
408                 return;
409
410         rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
411
412         shared_sint.masked = 1;
413
414         /* Need to correctly cleanup in the case of SMP!!! */
415         /* Disable the interrupt */
416         wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
417
418         rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
419         simp.simp_enabled = 0;
420         simp.base_simp_gpa = 0;
421
422         wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
423
424         rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
425         siefp.siefp_enabled = 0;
426         siefp.base_siefp_gpa = 0;
427
428         wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
429
430         free_page((unsigned long)hv_context.synic_message_page[cpu]);
431         free_page((unsigned long)hv_context.synic_event_page[cpu]);
432         free_page((unsigned long)hv_context.post_msg_page[cpu]);
433 }