hypercall.h

  1/******************************************************************************
  2 * hypercall.h
  3 *
  4 * Linux-specific hypervisor handling.
  5 *
  6 * Copyright (c) 2002-2004, K A Fraser
  7 *
  8 * This program is free software; you can redistribute it and/or
  9 * modify it under the terms of the GNU General Public License version 2
 10 * as published by the Free Software Foundation; or, when distributed
 11 * separately from the Linux kernel or incorporated into other
 12 * software packages, subject to the following license:
 13 *
 14 * Permission is hereby granted, free of charge, to any person obtaining a copy
 15 * of this source file (the "Software"), to deal in the Software without
 16 * restriction, including without limitation the rights to use, copy, modify,
 17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 18 * and to permit persons to whom the Software is furnished to do so, subject to
 19 * the following conditions:
 20 *
 21 * The above copyright notice and this permission notice shall be included in
 22 * all copies or substantial portions of the Software.
 23 *
 24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 30 * IN THE SOFTWARE.
 31 */
 32
 33#ifndef _ASM_X86_XEN_HYPERCALL_H
 34#define _ASM_X86_XEN_HYPERCALL_H
 35
 36#include <linux/kernel.h>
 37#include <linux/spinlock.h>
 38#include <linux/errno.h>
 39#include <linux/string.h>
 40#include <linux/types.h>
 41#include <linux/pgtable.h>
 42#include <linux/instrumentation.h>
 43
 44#include <trace/events/xen.h>
 45
 46#include <asm/alternative.h>
 47#include <asm/page.h>
 48#include <asm/smap.h>
 49#include <asm/nospec-branch.h>
 50
 51#include <xen/interface/xen.h>
 52#include <xen/interface/sched.h>
 53#include <xen/interface/physdev.h>
 54#include <xen/interface/platform.h>
 55#include <xen/interface/xen-mca.h>
 56
 57struct xen_dm_op_buf;
 58
 59/*
 60 * The hypercall asms have to meet several constraints:
 61 * - Work on 32- and 64-bit.
 62 *    The two architectures put their arguments in different sets of
 63 *    registers.
 64 *
 65 * - Work around asm syntax quirks
 66 *    It isn't possible to specify one of the rNN registers in a
 67 *    constraint, so we use explicit register variables to get the
 68 *    args into the right place.
 69 *
 70 * - Mark all registers as potentially clobbered
 71 *    Even unused parameters can be clobbered by the hypervisor, so we
 72 *    need to make sure gcc knows it.
 73 *
 74 * - Avoid compiler bugs.
 75 *    This is the tricky part.  Because x86_32 has such a constrained
 76 *    register set, gcc versions below 4.3 have trouble generating
 77 *    code when all the arg registers and memory are trashed by the
 78 *    asm.  There are syntactically simpler ways of achieving the
 79 *    semantics below, but they cause the compiler to crash.
 80 *
 81 *    The only combination I found which works is:
 82 *     - assign the __argX variables first
 83 *     - list all actually used parameters as "+r" (__argX)
 84 *     - clobber the rest
 85 *
 86 * The result certainly isn't pretty, and it really shows up cpp's
 87 * weakness as a macro language.  Sorry.  (But let's just give thanks
 88 * there aren't more than 5 arguments...)
 89 */
 90
 91void xen_hypercall_func(void);
 92DECLARE_STATIC_CALL(xen_hypercall, xen_hypercall_func);
 93
 94#ifdef MODULE
 95#define __ADDRESSABLE_xen_hypercall
 96#else
 97#define __ADDRESSABLE_xen_hypercall \
 98	__stringify(.global STATIC_CALL_KEY(xen_hypercall);)
 99#endif
100
101#define __HYPERCALL					\
102	__ADDRESSABLE_xen_hypercall			\
103	__stringify(call STATIC_CALL_TRAMP(xen_hypercall))
104
105#define __HYPERCALL_ENTRY(x)	"a" (x)
106
107#ifdef CONFIG_X86_32
108#define __HYPERCALL_RETREG	"eax"
109#define __HYPERCALL_ARG1REG	"ebx"
110#define __HYPERCALL_ARG2REG	"ecx"
111#define __HYPERCALL_ARG3REG	"edx"
112#define __HYPERCALL_ARG4REG	"esi"
113#define __HYPERCALL_ARG5REG	"edi"
114#else
115#define __HYPERCALL_RETREG	"rax"
116#define __HYPERCALL_ARG1REG	"rdi"
117#define __HYPERCALL_ARG2REG	"rsi"
118#define __HYPERCALL_ARG3REG	"rdx"
119#define __HYPERCALL_ARG4REG	"r10"
120#define __HYPERCALL_ARG5REG	"r8"
121#endif
122
123#define __HYPERCALL_DECLS						\
124	register unsigned long __res  asm(__HYPERCALL_RETREG);		\
125	register unsigned long __arg1 asm(__HYPERCALL_ARG1REG) = __arg1; \
126	register unsigned long __arg2 asm(__HYPERCALL_ARG2REG) = __arg2; \
127	register unsigned long __arg3 asm(__HYPERCALL_ARG3REG) = __arg3; \
128	register unsigned long __arg4 asm(__HYPERCALL_ARG4REG) = __arg4; \
129	register unsigned long __arg5 asm(__HYPERCALL_ARG5REG) = __arg5;
130
131#define __HYPERCALL_0PARAM	"=r" (__res), ASM_CALL_CONSTRAINT
132#define __HYPERCALL_1PARAM	__HYPERCALL_0PARAM, "+r" (__arg1)
133#define __HYPERCALL_2PARAM	__HYPERCALL_1PARAM, "+r" (__arg2)
134#define __HYPERCALL_3PARAM	__HYPERCALL_2PARAM, "+r" (__arg3)
135#define __HYPERCALL_4PARAM	__HYPERCALL_3PARAM, "+r" (__arg4)
136#define __HYPERCALL_5PARAM	__HYPERCALL_4PARAM, "+r" (__arg5)
137
138#define __HYPERCALL_0ARG()
139#define __HYPERCALL_1ARG(a1)						\
140	__HYPERCALL_0ARG()		__arg1 = (unsigned long)(a1);
141#define __HYPERCALL_2ARG(a1,a2)						\
142	__HYPERCALL_1ARG(a1)		__arg2 = (unsigned long)(a2);
143#define __HYPERCALL_3ARG(a1,a2,a3)					\
144	__HYPERCALL_2ARG(a1,a2)		__arg3 = (unsigned long)(a3);
145#define __HYPERCALL_4ARG(a1,a2,a3,a4)					\
146	__HYPERCALL_3ARG(a1,a2,a3)	__arg4 = (unsigned long)(a4);
147#define __HYPERCALL_5ARG(a1,a2,a3,a4,a5)				\
148	__HYPERCALL_4ARG(a1,a2,a3,a4)	__arg5 = (unsigned long)(a5);
149
150#define __HYPERCALL_CLOBBER5	"memory"
151#define __HYPERCALL_CLOBBER4	__HYPERCALL_CLOBBER5, __HYPERCALL_ARG5REG
152#define __HYPERCALL_CLOBBER3	__HYPERCALL_CLOBBER4, __HYPERCALL_ARG4REG
153#define __HYPERCALL_CLOBBER2	__HYPERCALL_CLOBBER3, __HYPERCALL_ARG3REG
154#define __HYPERCALL_CLOBBER1	__HYPERCALL_CLOBBER2, __HYPERCALL_ARG2REG
155#define __HYPERCALL_CLOBBER0	__HYPERCALL_CLOBBER1, __HYPERCALL_ARG1REG
156
157#define _hypercall0(type, name)						\
158({									\
159	__HYPERCALL_DECLS;						\
160	__HYPERCALL_0ARG();						\
161	asm volatile (__HYPERCALL					\
162		      : __HYPERCALL_0PARAM				\
163		      : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name)	\
164		      : __HYPERCALL_CLOBBER0);				\
165	(type)__res;							\
166})
167
168#define _hypercall1(type, name, a1)					\
169({									\
170	__HYPERCALL_DECLS;						\
171	__HYPERCALL_1ARG(a1);						\
172	asm volatile (__HYPERCALL					\
173		      : __HYPERCALL_1PARAM				\
174		      : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name)	\
175		      : __HYPERCALL_CLOBBER1);				\
176	(type)__res;							\
177})
178
179#define _hypercall2(type, name, a1, a2)					\
180({									\
181	__HYPERCALL_DECLS;						\
182	__HYPERCALL_2ARG(a1, a2);					\
183	asm volatile (__HYPERCALL					\
184		      : __HYPERCALL_2PARAM				\
185		      : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name)	\
186		      : __HYPERCALL_CLOBBER2);				\
187	(type)__res;							\
188})
189
190#define _hypercall3(type, name, a1, a2, a3)				\
191({									\
192	__HYPERCALL_DECLS;						\
193	__HYPERCALL_3ARG(a1, a2, a3);					\
194	asm volatile (__HYPERCALL					\
195		      : __HYPERCALL_3PARAM				\
196		      : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name)	\
197		      : __HYPERCALL_CLOBBER3);				\
198	(type)__res;							\
199})
200
201#define _hypercall4(type, name, a1, a2, a3, a4)				\
202({									\
203	__HYPERCALL_DECLS;						\
204	__HYPERCALL_4ARG(a1, a2, a3, a4);				\
205	asm volatile (__HYPERCALL					\
206		      : __HYPERCALL_4PARAM				\
207		      : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name)	\
208		      : __HYPERCALL_CLOBBER4);				\
209	(type)__res;							\
210})
211
212static inline long
213xen_single_call(unsigned int call,
214		unsigned long a1, unsigned long a2,
215		unsigned long a3, unsigned long a4,
216		unsigned long a5)
217{
218	__HYPERCALL_DECLS;
219	__HYPERCALL_5ARG(a1, a2, a3, a4, a5);
220
221	asm volatile(__HYPERCALL
222		     : __HYPERCALL_5PARAM
223		     : __HYPERCALL_ENTRY(call)
224		     : __HYPERCALL_CLOBBER5);
225
226	return (long)__res;
227}
228
229static __always_inline void __xen_stac(void)
230{
231	/*
232	 * Suppress objtool seeing the STAC/CLAC and getting confused about it
233	 * calling random code with AC=1.
234	 */
235	asm volatile(ASM_STAC_UNSAFE ::: "memory", "flags");
236}
237
238static __always_inline void __xen_clac(void)
239{
240	asm volatile(ASM_CLAC_UNSAFE ::: "memory", "flags");
241}
242
243static inline long
244privcmd_call(unsigned int call,
245	     unsigned long a1, unsigned long a2,
246	     unsigned long a3, unsigned long a4,
247	     unsigned long a5)
248{
249	long res;
250
251	__xen_stac();
252	res = xen_single_call(call, a1, a2, a3, a4, a5);
253	__xen_clac();
254
255	return res;
256}
257
258#ifdef CONFIG_XEN_PV
259static inline int
260HYPERVISOR_set_trap_table(struct trap_info *table)
261{
262	return _hypercall1(int, set_trap_table, table);
263}
264
265static inline int
266HYPERVISOR_mmu_update(struct mmu_update *req, int count,
267		      int *success_count, domid_t domid)
268{
269	return _hypercall4(int, mmu_update, req, count, success_count, domid);
270}
271
272static inline int
273HYPERVISOR_mmuext_op(struct mmuext_op *op, int count,
274		     int *success_count, domid_t domid)
275{
276	return _hypercall4(int, mmuext_op, op, count, success_count, domid);
277}
278
279static inline int
280HYPERVISOR_set_gdt(unsigned long *frame_list, int entries)
281{
282	return _hypercall2(int, set_gdt, frame_list, entries);
283}
284
285static inline int
286HYPERVISOR_callback_op(int cmd, void *arg)
287{
288	return _hypercall2(int, callback_op, cmd, arg);
289}
290
291static __always_inline int
292HYPERVISOR_set_debugreg(int reg, unsigned long value)
293{
294	return _hypercall2(int, set_debugreg, reg, value);
295}
296
297static __always_inline unsigned long
298HYPERVISOR_get_debugreg(int reg)
299{
300	return _hypercall1(unsigned long, get_debugreg, reg);
301}
302
303static inline int
304HYPERVISOR_update_descriptor(u64 ma, u64 desc)
305{
306	return _hypercall2(int, update_descriptor, ma, desc);
307}
308
309static inline int
310HYPERVISOR_update_va_mapping(unsigned long va, pte_t new_val,
311			     unsigned long flags)
312{
313	return _hypercall3(int, update_va_mapping, va, new_val.pte, flags);
314}
315
316static inline int
317HYPERVISOR_set_segment_base(int reg, unsigned long value)
318{
319	return _hypercall2(int, set_segment_base, reg, value);
320}
321
322static inline void
323MULTI_fpu_taskswitch(struct multicall_entry *mcl, int set)
324{
325	mcl->op = __HYPERVISOR_fpu_taskswitch;
326	mcl->args[0] = set;
327
328	trace_xen_mc_entry(mcl, 1);
329}
330
331static inline void
332MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,
333			pte_t new_val, unsigned long flags)
334{
335	mcl->op = __HYPERVISOR_update_va_mapping;
336	mcl->args[0] = va;
337	mcl->args[1] = new_val.pte;
338	mcl->args[2] = flags;
339
340	trace_xen_mc_entry(mcl, 3);
341}
342
343static inline void
344MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
345			struct desc_struct desc)
346{
347	mcl->op = __HYPERVISOR_update_descriptor;
348	mcl->args[0] = maddr;
349	mcl->args[1] = *(unsigned long *)&desc;
350
351	trace_xen_mc_entry(mcl, 2);
352}
353
354static inline void
355MULTI_mmu_update(struct multicall_entry *mcl, struct mmu_update *req,
356		 int count, int *success_count, domid_t domid)
357{
358	mcl->op = __HYPERVISOR_mmu_update;
359	mcl->args[0] = (unsigned long)req;
360	mcl->args[1] = count;
361	mcl->args[2] = (unsigned long)success_count;
362	mcl->args[3] = domid;
363
364	trace_xen_mc_entry(mcl, 4);
365}
366
367static inline void
368MULTI_mmuext_op(struct multicall_entry *mcl, struct mmuext_op *op, int count,
369		int *success_count, domid_t domid)
370{
371	mcl->op = __HYPERVISOR_mmuext_op;
372	mcl->args[0] = (unsigned long)op;
373	mcl->args[1] = count;
374	mcl->args[2] = (unsigned long)success_count;
375	mcl->args[3] = domid;
376
377	trace_xen_mc_entry(mcl, 4);
378}
379
380static inline void
381MULTI_stack_switch(struct multicall_entry *mcl,
382		   unsigned long ss, unsigned long esp)
383{
384	mcl->op = __HYPERVISOR_stack_switch;
385	mcl->args[0] = ss;
386	mcl->args[1] = esp;
387
388	trace_xen_mc_entry(mcl, 2);
389}
390#endif
391
392static __always_inline int
393HYPERVISOR_sched_op(int cmd, void *arg)
394{
395	return _hypercall2(int, sched_op, cmd, arg);
396}
397
398static inline long
399HYPERVISOR_set_timer_op(u64 timeout)
400{
401	unsigned long timeout_hi = (unsigned long)(timeout>>32);
402	unsigned long timeout_lo = (unsigned long)timeout;
403	return _hypercall2(long, set_timer_op, timeout_lo, timeout_hi);
404}
405
406static inline int
407HYPERVISOR_mca(struct xen_mc *mc_op)
408{
409	mc_op->interface_version = XEN_MCA_INTERFACE_VERSION;
410	return _hypercall1(int, mca, mc_op);
411}
412
413static inline int
414HYPERVISOR_platform_op(struct xen_platform_op *op)
415{
416	op->interface_version = XENPF_INTERFACE_VERSION;
417	return _hypercall1(int, platform_op, op);
418}
419
420static inline long
421HYPERVISOR_memory_op(unsigned int cmd, void *arg)
422{
423	return _hypercall2(long, memory_op, cmd, arg);
424}
425
426static inline int
427HYPERVISOR_multicall(void *call_list, uint32_t nr_calls)
428{
429	return _hypercall2(int, multicall, call_list, nr_calls);
430}
431
432static inline int
433HYPERVISOR_event_channel_op(int cmd, void *arg)
434{
435	return _hypercall2(int, event_channel_op, cmd, arg);
436}
437
438static __always_inline int
439HYPERVISOR_xen_version(int cmd, void *arg)
440{
441	return _hypercall2(int, xen_version, cmd, arg);
442}
443
444static inline int
445HYPERVISOR_console_io(int cmd, int count, char *str)
446{
447	return _hypercall3(int, console_io, cmd, count, str);
448}
449
450static inline int
451HYPERVISOR_physdev_op(int cmd, void *arg)
452{
453	return _hypercall2(int, physdev_op, cmd, arg);
454}
455
456static inline int
457HYPERVISOR_grant_table_op(unsigned int cmd, void *uop, unsigned int count)
458{
459	return _hypercall3(int, grant_table_op, cmd, uop, count);
460}
461
462static inline int
463HYPERVISOR_vm_assist(unsigned int cmd, unsigned int type)
464{
465	return _hypercall2(int, vm_assist, cmd, type);
466}
467
468static inline int
469HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args)
470{
471	return _hypercall3(int, vcpu_op, cmd, vcpuid, extra_args);
472}
473
474static inline int
475HYPERVISOR_suspend(unsigned long start_info_mfn)
476{
477	struct sched_shutdown r = { .reason = SHUTDOWN_suspend };
478
479	/*
480	 * For a PV guest the tools require that the start_info mfn be
481	 * present in rdx/edx when the hypercall is made. Per the
482	 * hypercall calling convention this is the third hypercall
483	 * argument, which is start_info_mfn here.
484	 */
485	return _hypercall3(int, sched_op, SCHEDOP_shutdown, &r, start_info_mfn);
486}
487
488static inline unsigned long __must_check
489HYPERVISOR_hvm_op(int op, void *arg)
490{
491       return _hypercall2(unsigned long, hvm_op, op, arg);
492}
493
494static inline int
495HYPERVISOR_xenpmu_op(unsigned int op, void *arg)
496{
497	return _hypercall2(int, xenpmu_op, op, arg);
498}
499
500static inline int
501HYPERVISOR_dm_op(
502	domid_t dom, unsigned int nr_bufs, struct xen_dm_op_buf *bufs)
503{
504	int ret;
505	__xen_stac();
506	ret = _hypercall3(int, dm_op, dom, nr_bufs, bufs);
507	__xen_clac();
508	return ret;
509}
510
511#endif /* _ASM_X86_XEN_HYPERCALL_H */