timesupref.h@ 86296

Last change on this file since 86296 was 82968, checked in by vboxsync, 5 years ago
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1	/* $Id: timesupref.h 82968 2020-02-04 10:35:17Z vboxsync $ */
2	/** @file
3	* IPRT - Time using SUPLib, the C Code Template.
4	*/
5
6	/*
7	* Copyright (C) 2006-2020 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/**
29	* The C reference implementation of the assembly routines.
30	*
31	* Calculate NanoTS using the information in the global information page (GIP)
32	* which the support library (SUPLib) exports.
33	*
34	* This function guarantees that the returned timestamp is later (in time) than
35	* any previous calls in the same thread.
36	*
37	* @remark The way the ever increasing time guarantee is currently implemented means
38	* that if you call this function at a frequency higher than 1GHz you're in for
39	* trouble. We currently assume that no idiot will do that for real life purposes.
40	*
41	* @returns Nanosecond timestamp.
42	* @param pData Pointer to the data structure.
43	*/
44	RTDECL(uint64_t) rtTimeNanoTSInternalRef(PRTTIMENANOTSDATA pData)
45	{
46	#if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA && defined(IN_RING3)
47	PSUPGIPCPU pGipCpuAttemptedTscRecalibration = NULL;
48	#endif
49	AssertCompile(RT_IS_POWER_OF_TWO(RTCPUSET_MAX_CPUS));
50
51	for (;;)
52	{
53	#ifndef IN_RING3 /* This simplifies and improves everything. */
54	RTCCUINTREG const uFlags = ASMIntDisableFlags();
55	#endif
56
57	/*
58	* Check that the GIP is sane and that the premises for this worker function
59	* hasn't changed (CPU onlined with bad delta or missing features).
60	*/
61	PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
62	if ( RT_LIKELY(pGip)
63	&& RT_LIKELY(pGip->u32Magic == SUPGLOBALINFOPAGE_MAGIC)
64	#if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA
65	&& RT_LIKELY(pGip->enmUseTscDelta >= SUPGIPUSETSCDELTA_PRACTICALLY_ZERO)
66	#else
67	&& RT_LIKELY(pGip->enmUseTscDelta <= SUPGIPUSETSCDELTA_ROUGHLY_ZERO)
68	#endif
69	#if defined(IN_RING3) && TMPL_GET_CPU_METHOD != 0
70	&& RT_LIKELY(pGip->fGetGipCpu & TMPL_GET_CPU_METHOD)
71	#endif
72	)
73	{
74	/*
75	* Resolve pGipCpu if needed. If the instruction is serializing, we
76	* read the transaction id first if possible.
77	*/
78	#if TMPL_MODE == TMPL_MODE_ASYNC \|\| TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA
79	# if defined(IN_RING0)
80	uint32_t const iCpuSet = RTMpCurSetIndex();
81	uint16_t const iGipCpu = iCpuSet < RT_ELEMENTS(pGip->aiCpuFromCpuSetIdx)
82	? pGip->aiCpuFromCpuSetIdx[iCpuSet] : UINT16_MAX;
83	# elif defined(IN_RC)
84	uint32_t const iCpuSet = VMMGetCpu(&g_VM)->iHostCpuSet;
85	uint16_t const iGipCpu = iCpuSet < RT_ELEMENTS(pGip->aiCpuFromCpuSetIdx)
86	? pGip->aiCpuFromCpuSetIdx[iCpuSet] : UINT16_MAX;
87	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID
88	# if TMPL_MODE != TMPL_MODE_ASYNC
89	uint32_t const u32TransactionId = pGip->aCPUs[0].u32TransactionId;
90	# endif
91	uint8_t const idApic = ASMGetApicId();
92	uint16_t const iGipCpu = pGip->aiCpuFromApicId[idApic];
93	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID_EXT_0B
94	# if TMPL_MODE != TMPL_MODE_ASYNC
95	uint32_t const u32TransactionId = pGip->aCPUs[0].u32TransactionId;
96	# endif
97	uint32_t const idApic = ASMGetApicIdExt0B();
98	uint16_t const iGipCpu = pGip->aiCpuFromApicId[idApic];
99	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID_EXT_8000001E
100	# if TMPL_MODE != TMPL_MODE_ASYNC
101	uint32_t const u32TransactionId = pGip->aCPUs[0].u32TransactionId;
102	# endif
103	uint32_t const idApic = ASMGetApicIdExt8000001E();
104	uint16_t const iGipCpu = pGip->aiCpuFromApicId[idApic];
105	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_MASK_MAX_SET_CPUS \
106	\|\| TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_GROUP_IN_CH_NUMBER_IN_CL
107	# if TMPL_MODE != TMPL_MODE_ASYNC
108	uint32_t const u32TransactionId = pGip->aCPUs[0].u32TransactionId;
109	# endif
110	uint32_t uAux;
111	ASMReadTscWithAux(&uAux);
112	# if TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_MASK_MAX_SET_CPUS
113	uint16_t const iCpuSet = uAux & (RTCPUSET_MAX_CPUS - 1);
114	# else
115	uint16_t iCpuSet = 0;
116	uint16_t offGipCpuGroup = pGip->aoffCpuGroup[(uAux >> 8) & UINT8_MAX];
117	if (offGipCpuGroup < pGip->cPages * PAGE_SIZE)
118	{
119	PSUPGIPCPUGROUP pGipCpuGroup = (PSUPGIPCPUGROUP)((uintptr_t)pGip + offGipCpuGroup);
120	if ( (uAux & UINT8_MAX) < pGipCpuGroup->cMaxMembers
121	&& pGipCpuGroup->aiCpuSetIdxs[uAux & UINT8_MAX] != -1)
122	iCpuSet = pGipCpuGroup->aiCpuSetIdxs[uAux & UINT8_MAX];
123	}
124	# endif
125	uint16_t const iGipCpu = pGip->aiCpuFromCpuSetIdx[iCpuSet];
126	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_IDTR_LIMIT_MASK_MAX_SET_CPUS
127	uint16_t const cbLim = ASMGetIdtrLimit();
128	uint16_t const iCpuSet = (cbLim - 256 * (ARCH_BITS == 64 ? 16 : 8)) & (RTCPUSET_MAX_CPUS - 1);
129	uint16_t const iGipCpu = pGip->aiCpuFromCpuSetIdx[iCpuSet];
130	# else
131	# error "What?"
132	# endif
133	if (RT_LIKELY(iGipCpu < pGip->cCpus))
134	{
135	PSUPGIPCPU pGipCpu = &pGip->aCPUs[iGipCpu];
136	#else
137	{
138	#endif
139	/*
140	* Get the transaction ID if necessary and we haven't already
141	* read it before a serializing instruction above. We can skip
142	* this for ASYNC_TSC mode in ring-0 and raw-mode context since
143	* we disable interrupts.
144	*/
145	#if TMPL_MODE == TMPL_MODE_ASYNC && defined(IN_RING3)
146	uint32_t const u32TransactionId = pGipCpu->u32TransactionId;
147	ASMCompilerBarrier();
148	TMPL_READ_FENCE();
149	#elif TMPL_MODE != TMPL_MODE_ASYNC \
150	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID \
151	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_0B \
152	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_8000001E \
153	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_RDTSCP_MASK_MAX_SET_CPUS \
154	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_RDTSCP_GROUP_IN_CH_NUMBER_IN_CL
155	uint32_t const u32TransactionId = pGip->aCPUs[0].u32TransactionId;
156	ASMCompilerBarrier();
157	TMPL_READ_FENCE();
158	#endif
159
160	/*
161	* Gather all the data we need. The mess at the end is to make
162	* sure all loads are done before we recheck the transaction ID
163	* without triggering serializing twice.
164	*/
165	uint32_t u32NanoTSFactor0 = pGip->u32UpdateIntervalNS;
166	#if TMPL_MODE == TMPL_MODE_ASYNC
167	uint32_t u32UpdateIntervalTSC = pGipCpu->u32UpdateIntervalTSC;
168	uint64_t u64NanoTS = pGipCpu->u64NanoTS;
169	uint64_t u64TSC = pGipCpu->u64TSC;
170	#else
171	uint32_t u32UpdateIntervalTSC = pGip->aCPUs[0].u32UpdateIntervalTSC;
172	uint64_t u64NanoTS = pGip->aCPUs[0].u64NanoTS;
173	uint64_t u64TSC = pGip->aCPUs[0].u64TSC;
174	# if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA
175	int64_t i64TscDelta = pGipCpu->i64TSCDelta;
176	# endif
177	#endif
178	uint64_t u64PrevNanoTS = ASMAtomicUoReadU64(pData->pu64Prev);
179	#if TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_MASK_MAX_SET_CPUS \
180	\|\| TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_GROUP_IN_CH_NUMBER_IN_CL
181	ASMCompilerBarrier();
182	uint32_t uAux2;
183	uint64_t u64Delta = ASMReadTscWithAux(&uAux2); /* serializing */
184	#else
185	uint64_t u64Delta = ASMReadTSC();
186	ASMCompilerBarrier();
187	# if TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID /* getting APIC will serialize */ \
188	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_0B \
189	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_8000001E \
190	&& (defined(IN_RING3) \|\| TMPL_MODE != TMPL_MODE_ASYNC)
191	TMPL_READ_FENCE(); /* Expensive (~30 ticks). Would like convincing argumentation that let us remove it. */
192	# endif
193	#endif
194
195	/*
196	* Check that we didn't change CPU.
197	*/
198	#if defined(IN_RING3) && ( TMPL_MODE == TMPL_MODE_ASYNC \|\| TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA )
199	# if TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID
200	if (RT_LIKELY(ASMGetApicId() == idApic))
201	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID_EXT_0B
202	if (RT_LIKELY(ASMGetApicIdExt0B() == idApic))
203	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_APIC_ID_EXT_8000001E
204	if (RT_LIKELY(ASMGetApicIdExt8000001E() == idApic))
205	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_MASK_MAX_SET_CPUS \
206	\|\| TMPL_GET_CPU_METHOD == SUPGIPGETCPU_RDTSCP_GROUP_IN_CH_NUMBER_IN_CL
207	if (RT_LIKELY(uAux2 == uAux))
208	# elif TMPL_GET_CPU_METHOD == SUPGIPGETCPU_IDTR_LIMIT_MASK_MAX_SET_CPUS
209	if (RT_LIKELY(ASMGetIdtrLimit() == cbLim))
210	# endif
211	#endif
212	{
213	/*
214	* Check the transaction ID (see above for R0/RC + ASYNC).
215	*/
216	#if defined(IN_RING3) \|\| TMPL_MODE != TMPL_MODE_ASYNC
217	# if TMPL_MODE == TMPL_MODE_ASYNC
218	if (RT_LIKELY(pGipCpu->u32TransactionId == u32TransactionId && !(u32TransactionId & 1) ))
219	# else
220	if (RT_LIKELY(pGip->aCPUs[0].u32TransactionId == u32TransactionId && !(u32TransactionId & 1) ))
221	# endif
222	#endif
223	{
224
225	/*
226	* Apply the TSC delta. If the delta is invalid and the
227	* execution allows it, try trigger delta recalibration.
228	*/
229	#if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA && defined(IN_RING3)
230	if (RT_LIKELY( i64TscDelta != INT64_MAX
231	\|\| pGipCpu == pGipCpuAttemptedTscRecalibration))
232	#endif
233	{
234	#if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA
235	# ifndef IN_RING3
236	if (RT_LIKELY(i64TscDelta != INT64_MAX))
237	# endif
238	u64Delta -= i64TscDelta;
239	#endif
240
241	/*
242	* Bingo! We've got a consistent set of data.
243	*/
244	#ifndef IN_RING3
245	ASMSetFlags(uFlags);
246	#endif
247
248	/*
249	* Calc NanoTS delta.
250	*/
251	u64Delta -= u64TSC;
252	if (RT_LIKELY(u64Delta <= u32UpdateIntervalTSC))
253	{ /* MSVC branch hint, probably pointless. */ }
254	else
255	{
256	/*
257	* We've expired the interval, cap it. If we're here for the 2nd
258	* time without any GIP update in-between, the checks against
259	* *pu64Prev below will force 1ns stepping.
260	*/
261	ASMAtomicIncU32(&pData->cExpired);
262	u64Delta = u32UpdateIntervalTSC;
263	}
264	#if !defined(_MSC_VER) \|\| !defined(RT_ARCH_X86) /* GCC makes very pretty code from these two inline calls, while MSC cannot. */
265	u64Delta = ASMMult2xU32RetU64((uint32_t)u64Delta, u32NanoTSFactor0);
266	u64Delta = ASMDivU64ByU32RetU32(u64Delta, u32UpdateIntervalTSC);
267	#else
268	__asm
269	{
270	mov eax, dword ptr [u64Delta]
271	mul dword ptr [u32NanoTSFactor0]
272	div dword ptr [u32UpdateIntervalTSC]
273	mov dword ptr [u64Delta], eax
274	xor edx, edx
275	mov dword ptr [u64Delta + 4], edx
276	}
277	#endif
278
279	/*
280	* Calculate the time and compare it with the previously returned value.
281	*/
282	u64NanoTS += u64Delta;
283	uint64_t u64DeltaPrev = u64NanoTS - u64PrevNanoTS;
284	if (RT_LIKELY( u64DeltaPrev > 0
285	&& u64DeltaPrev < UINT64_C(86000000000000) /* 24h */))
286	{ /* Frequent - less than 24h since last call. */ }
287	else if (RT_LIKELY( (int64_t)u64DeltaPrev <= 0
288	&& (int64_t)u64DeltaPrev + u32NanoTSFactor0 * 2 >= 0))
289	{
290	/* Occasional - u64NanoTS is in the recent 'past' relative the previous call. */
291	ASMAtomicIncU32(&pData->c1nsSteps);
292	u64NanoTS = u64PrevNanoTS + 1;
293	}
294	else if (!u64PrevNanoTS)
295	/* We're resuming (see TMVirtualResume). */;
296	else
297	{
298	/* Something has gone bust, if negative offset it's real bad. */
299	ASMAtomicIncU32(&pData->cBadPrev);
300	pData->pfnBad(pData, u64NanoTS, u64DeltaPrev, u64PrevNanoTS);
301	}
302
303	/*
304	* Attempt updating the previous value, provided we're still ahead of it.
305	*
306	* There is no point in recalculating u64NanoTS because we got preempted or if
307	* we raced somebody while the GIP was updated, since these are events
308	* that might occur at any point in the return path as well.
309	*/
310	if (RT_LIKELY(ASMAtomicCmpXchgU64(pData->pu64Prev, u64NanoTS, u64PrevNanoTS)))
311	return u64NanoTS;
312
313	ASMAtomicIncU32(&pData->cUpdateRaces);
314	for (int cTries = 25; cTries > 0; cTries--)
315	{
316	u64PrevNanoTS = ASMAtomicReadU64(pData->pu64Prev);
317	if (u64PrevNanoTS >= u64NanoTS)
318	break;
319	if (ASMAtomicCmpXchgU64(pData->pu64Prev, u64NanoTS, u64PrevNanoTS))
320	break;
321	ASMNopPause();
322	}
323	return u64NanoTS;
324	}
325
326	#if TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA && defined(IN_RING3)
327	/*
328	* Call into the support driver to try make it recalculate the delta. We
329	* remember which GIP CPU structure we're probably working on so we won't
330	* end up in a loop if the driver for some reason cannot get the job done.
331	*/
332	else /* else is unecessary, but helps checking the preprocessor spaghetti. */
333	{
334	pGipCpuAttemptedTscRecalibration = pGipCpu;
335	uint64_t u64TscTmp;
336	uint16_t idApicUpdate;
337	int rc = SUPR3ReadTsc(&u64TscTmp, &idApicUpdate);
338	if (RT_SUCCESS(rc) && idApicUpdate < RT_ELEMENTS(pGip->aiCpuFromApicId))
339	{
340	uint32_t iUpdateGipCpu = pGip->aiCpuFromApicId[idApicUpdate];
341	if (iUpdateGipCpu < pGip->cCpus)
342	pGipCpuAttemptedTscRecalibration = &pGip->aCPUs[iUpdateGipCpu];
343	}
344	}
345	#endif
346	}
347	}
348
349	/*
350	* No joy must try again.
351	*/
352	#ifdef _MSC_VER
353	# pragma warning(disable: 4702)
354	#endif
355	#ifndef IN_RING3
356	ASMSetFlags(uFlags);
357	#endif
358	ASMNopPause();
359	continue;
360	}
361
362	#if TMPL_MODE == TMPL_MODE_ASYNC \|\| TMPL_MODE == TMPL_MODE_SYNC_INVAR_WITH_DELTA
363	/*
364	* We've got a bad CPU or APIC index of some kind.
365	*/
366	else /* else is unecessary, but helps checking the preprocessor spaghetti. */
367	{
368	# ifndef IN_RING3
369	ASMSetFlags(uFlags);
370	# endif
371	# if defined(IN_RING0) \
372	\|\| defined(IN_RC) \
373	\|\| ( TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID \
374	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_0B /?/ \
375	&& TMPL_GET_CPU_METHOD != SUPGIPGETCPU_APIC_ID_EXT_8000001E /?/)
376	return pData->pfnBadCpuIndex(pData, UINT16_MAX-1, iCpuSet, iGipCpu);
377	# else
378	return pData->pfnBadCpuIndex(pData, idApic, UINT16_MAX-1, iGipCpu);
379	# endif
380	}
381	#endif
382	}
383
384	/*
385	* Something changed in the GIP config or it was unmapped, figure out
386	* the right worker function to use now.
387	*/
388	#ifndef IN_RING3
389	ASMSetFlags(uFlags);
390	#endif
391	return pData->pfnRediscover(pData);
392	}
393	}
394

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source: vbox/trunk/src/VBox/Runtime/common/time/timesupref.h@ 86296

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