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Re: [Minios-devel] [UNIKRAFT PATCH 3/3] plat/kvm: Add KVM (x86_64) timer support
See my comments inline.
On 05.04.2018 17:21, Costin Lupu wrote:
We are using TSC clock as main timer on KVM.
Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
plat/kvm/Makefile.uk | 3 +
plat/kvm/clock_subr.c | 226 ++++++++++++++++++++++++
plat/kvm/include/kvm/clock_subr.h | 83 +++++++++
plat/kvm/include/kvm/tscclock.h | 42 +++++
plat/kvm/irq.c | 10 ++
plat/kvm/time.c | 62 +++++++
plat/kvm/tscclock.c | 356 ++++++++++++++++++++++++++++++++++++++
7 files changed, 782 insertions(+)
create mode 100644 plat/kvm/clock_subr.c
create mode 100644 plat/kvm/include/kvm/clock_subr.h
create mode 100644 plat/kvm/include/kvm/tscclock.h
create mode 100644 plat/kvm/time.c
create mode 100644 plat/kvm/tscclock.c
diff --git a/plat/kvm/Makefile.uk b/plat/kvm/Makefile.uk
index 46258ff..76c40f1 100644
--- a/plat/kvm/Makefile.uk
+++ b/plat/kvm/Makefile.uk
@@ -34,4 +34,7 @@ LIBKVMPLAT_SRCS-$(ARCH_X86_64) +=
$(LIBKVMPLAT_BASE)/x86/intctrl.c
LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/shutdown.c
LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/memory.c
LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/irq.c
+LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/time.c
+LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/tscclock.c
+LIBKVMPLAT_SRCS-y += $(LIBKVMPLAT_BASE)/clock_subr.c
LIBKVMPLAT_SRCS-y += $(UK_PLAT_COMMON_BASE)/lcpu.c|common
diff --git a/plat/kvm/clock_subr.c b/plat/kvm/clock_subr.c
new file mode 100644
index 0000000..6d7388b
--- /dev/null
+++ b/plat/kvm/clock_subr.c
@@ -0,0 +1,226 @@
+/* SPDX-License-Identifier: ISC */
I think this should be
/* SPDX-License-Identifier: ISC AND BSD-2-Clause-NetBSD AND BSD-3-Clause */
+/*
+ * Authors: Martin Lucina
+ * Ricardo Koller
+ * Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2015-2017 IBM
+ * Copyright (c) 2016-2017 Docker, Inc.
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation
+ *
+ * Permission to use, copy, modify, and/or distribute this software
+ * for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear
+ * in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Taken from solo5 clock_subr.c */
+
+/* $NetBSD: clock_subr.c,v 1.26 2014/12/22 18:09:20 christos Exp $ */
+
+/*-
+ * Copyright (c) 1996 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Gordon W. Ross
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Copyright (c) 1988 University of Utah.
+ * Copyright (c) 1982, 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * from: Utah $Hdr: clock.c 1.18 91/01/21$
+ *
+ * @(#)clock.c 8.2 (Berkeley) 1/12/94
+ */
+
+#include <kvm/clock_subr.h>
+
+/* Some handy constants. */
+#define SECS_PER_MINUTE 60
+#define SECS_PER_HOUR 3600
+#define SECS_PER_DAY 86400
+#define DAYS_PER_COMMON_YEAR 365
+#define DAYS_PER_LEAP_YEAR 366
+#define SECS_PER_COMMON_YEAR (SECS_PER_DAY * DAYS_PER_COMMON_YEAR)
+#define SECS_PER_LEAP_YEAR (SECS_PER_DAY * DAYS_PER_LEAP_YEAR)
+
+/* Traditional POSIX base year */
+#define POSIX_BASE_YEAR 1970
+
+/* Some handy functions */
+static int days_in_month(int m)
+{
+ switch (m) {
+ case 2:
+ return 28;
+ case 4: case 6: case 9: case 11:
+ return 30;
+ case 1: case 3: case 5: case 7: case 8: case 10: case 12:
+ return 31;
+ default:
+ return -1;
+ }
+}
+
+/*
+ * This inline avoids some unnecessary modulo operations
+ * as compared with the usual macro:
+ * ( ((year % 4) == 0 &&
+ * (year % 100) != 0) ||
+ * ((year % 400) == 0) )
+ * It is otherwise equivalent.
+ */
+static int is_leap_year(__u64 year)
+{
+ if ((year & 3) != 0)
+ return 0;
+
+ if ((year % 100) != 0)
+ return 1;
+
+ return (year % 400) == 0;
+}
+
+static int days_per_year(__u64 year)
+{
+ return is_leap_year(year) ? DAYS_PER_LEAP_YEAR : DAYS_PER_COMMON_YEAR;
+}
+
+/*
+ * Generic routines to convert between a POSIX date
+ * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
+ * Derived from arch/hp300/hp300/clock.c
+ */
+
+#define FEBRUARY 2
+
+/* for easier alignment:
+ * time from the epoch to 2000 (there were 7 leap years):
+ */
+#define DAYSTO2000 (365 * 30 + 7)
+
+/* 4 year intervals include 1 leap year */
+#define DAYS4YEARS (365 * 4 + 1)
+
+/* 100 year intervals include 24 leap years */
+#define DAYS100YEARS (365 * 100 + 24)
+
+/* 400 year intervals include 97 leap years */
+#define DAYS400YEARS (365 * 400 + 97)
+
In general, we should revisit the naming of functions that are
non-static. In order to avoid naming conflicts with application code
later, I would prefer adding the prefix _libkvmplat_ in order to mark
those functions as library-internal. Since, these are new files, can you
call it _libkvmplat_clock_ymdhms_to_secs()? You may also adopt this
scheme to the other functions that are non-static and not part of the
ukplat API.
I know that much more cleaning-up work of this sort has to be done but
we should start somewhere. I think doing this with new files and
functions is good start.
As we discussed off-line, I agree that we should introduce a design
principle document that explains considerations for Unikraft and library
APIs.
+__u64 clock_ymdhms_to_secs(struct bmk_clock_ymdhms *dt)
+{
+ __u64 secs, i, year, days;
+
+ year = dt->dt_year;
+
+ /*
+ * Compute days since start of time
+ * First from years, then from months.
+ */
+ if (year < POSIX_BASE_YEAR)
+ return 0;
+
+ days = 0;
+ if (is_leap_year(year) && dt->dt_mon > FEBRUARY)
+ days++;
+
+ if (year < 2000) {
+ /* simple way for early years */
+ for (i = POSIX_BASE_YEAR; i < year; i++)
+ days += days_per_year(i);
+
+ } else {
+ /* years are properly aligned */
+ days += DAYSTO2000;
+ year -= 2000;
+
+ i = year / 400;
+ days += i * DAYS400YEARS;
+ year -= i * 400;
+
+ i = year / 100;
+ days += i * DAYS100YEARS;
+ year -= i * 100;
+
+ i = year / 4;
+ days += i * DAYS4YEARS;
+ year -= i * 4;
+
+ for (i = dt->dt_year - year; i < dt->dt_year; i++)
+ days += days_per_year(i);
+ }
+
+ /* Months */
+ for (i = 1; i < dt->dt_mon; i++)
+ days += days_in_month(i);
+ days += (dt->dt_day - 1);
+
+ /* Add hours, minutes, seconds. */
+ secs = (((__u64) days
+ * 24 + dt->dt_hour)
+ * 60 + dt->dt_min)
+ * 60 + dt->dt_sec;
+
+ return secs;
+}
diff --git a/plat/kvm/include/kvm/clock_subr.h
b/plat/kvm/include/kvm/clock_subr.h
new file mode 100644
index 0000000..66f829b
--- /dev/null
+++ b/plat/kvm/include/kvm/clock_subr.h
@@ -0,0 +1,83 @@
/* SPDX-License-Identifier: ISC AND BSD-2-Clause-NetBSD */
+/* SPDX-License-Identifier: ISC */
+/*
+ * Authors: Martin Lucina
+ * Ricardo Koller
+ * Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2015-2017 IBM
+ * Copyright (c) 2016-2017 Docker, Inc.
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation
+ *
+ * Permission to use, copy, modify, and/or distribute this software
+ * for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear
+ * in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Taken from solo5 clock_subr.h */
+
+/*-
+ * Copyright (c) 1996 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Gordon W. Ross
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _BMK_CLOCK_SUBR_H_
+#define _BMK_CLOCK_SUBR_H_
+
+#include <uk/arch/types.h>
+
+/*
+ * "POSIX time" to/from "YY/MM/DD/hh/mm/ss"
+ */
+struct bmk_clock_ymdhms {
+ __u64 dt_year;
+ __u8 dt_mon;
+ __u8 dt_day;
+ __u8 dt_hour;
+ __u8 dt_min;
+ __u8 dt_sec;
+};
+
+__u64 clock_ymdhms_to_secs(struct bmk_clock_ymdhms *dt);
+
+/*
+ * BCD to binary.
+ */
+static inline unsigned int bcdtobin(unsigned int bcd)
+{
+ return ((bcd >> 4) & 0x0f) * 10 + (bcd & 0x0f);
+}
+
+#endif /* _BMK_CLOCK_SUBR_H_ */
diff --git a/plat/kvm/include/kvm/tscclock.h b/plat/kvm/include/kvm/tscclock.h
new file mode 100644
index 0000000..27d0e02
--- /dev/null
+++ b/plat/kvm/include/kvm/tscclock.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
+ */
+
+#ifndef __KVM_TSCCLOCK_H__
+#define __KVM_TSCCLOCK_H__
+
Same prefixing here? "_libkvmplat_" for kvmplat internal, or
"libkvmplat_" for KVM plat only provided functionality.
+int tscclock_init(void);
+__u64 tscclock_monotonic(void);
+__u64 tscclock_epochoffset(void);
+
+#endif /* __KVM_TSCCLOCK_H__ */
diff --git a/plat/kvm/irq.c b/plat/kvm/irq.c
index 55f8e67..a3b2121 100644
--- a/plat/kvm/irq.c
+++ b/plat/kvm/irq.c
@@ -68,12 +68,22 @@ void irq_register(unsigned long irq, irq_handler_func_t
func, void *arg)
intctrl_clear_irq(irq);
}
+/*
+ * TODO This is a temporary solution used to identify non TSC clock
+ * interrupts in order to stop waiting for interrupts with deadline.
+ */
+extern long nontsc_interrupt_assert;
+
void irq_handle(unsigned long irq)
{
struct irq_handler *h;
int handled = 0;
UK_SLIST_FOREACH(h, &irq_handlers[irq], entries) {
+ /* TODO define platform wise macro for timer IRQ number */
+ if (irq != 0)
+ nontsc_interrupt_assert = 1;
+
if (h->func(h->arg) == 1) {
handled = 1;
break;
diff --git a/plat/kvm/time.c b/plat/kvm/time.c
new file mode 100644
index 0000000..1276997
--- /dev/null
+++ b/plat/kvm/time.c
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: ISC */
+/*
+ * Authors: Dan Williams
+ * Martin Lucina
+ * Ricardo Koller
+ * Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2015-2017 IBM
+ * Copyright (c) 2016-2017 Docker, Inc.
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation
+ *
+ * Permission to use, copy, modify, and/or distribute this software
+ * for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear
+ * in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Taken from solo5 time.c */
+
+#include <stdlib.h>
+#include <uk/plat/time.h>
+#include <kvm/irq.h>
+#include <kvm/tscclock.h>
+#include <uk/assert.h>
+
+
+/* return ns since time_init() */
+__nsec ukplat_monotonic_clock(void)
+{
+ return tscclock_monotonic();
+}
+
+/* return wall time in nsecs */
+__nsec ukplat_clock_wall(void)
+{
+ return tscclock_monotonic() + tscclock_epochoffset();
+}
+
+static int timer_handler(void *arg __unused)
+{
+ /* Yes, we handled the irq. */
+ return 1;
+}
+
+/* must be called before interrupts are enabled */
+void ukplat_time_init(void)
+{
+ int rc;
+
+ irq_register(0, timer_handler, NULL);
+
+ rc = tscclock_init();
+ UK_ASSERT(rc == 0);
+}
diff --git a/plat/kvm/tscclock.c b/plat/kvm/tscclock.c
new file mode 100644
index 0000000..1199f18
--- /dev/null
+++ b/plat/kvm/tscclock.c
@@ -0,0 +1,356 @@
+/* SPDX-License-Identifier: ISC */
+/*
+ * Authors: Dan Williams
+ * Martin Lucina
+ * Ricardo Koller
+ * Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * Copyright (c) 2015-2017 IBM
+ * Copyright (c) 2016-2017 Docker, Inc.
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation
+ *
+ * Permission to use, copy, modify, and/or distribute this software
+ * for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear
+ * in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+ * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* Taken from solo5 tscclock.c */
+
+/*-
+ * Copyright (c) 2014, 2015 Antti Kantee. All Rights Reserved.
+ * Copyright (c) 2015 Martin Lucina. All Rights Reserved.
+ * Modified for solo5 by Ricardo Koller <kollerr@xxxxxxxxxx>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <uk/plat/lcpu.h>
+#include <uk/plat/time.h>
+#include <x86/cpu.h>
+#include <kvm/clock_subr.h>
+#include <uk/print.h>
+#include <uk/assert.h>
+
+#define NSEC_PER_SEC 1000000000ULL
+
+#define TIMER_CNTR 0x40
+#define TIMER_MODE 0x43
+#define TIMER_SEL0 0x00
+#define TIMER_LATCH 0x00
+#define TIMER_RATEGEN 0x04
+#define TIMER_ONESHOT 0x08
+#define TIMER_16BIT 0x30
+#define TIMER_HZ 1193182
+
+#define RTC_COMMAND 0x70
+#define RTC_DATA 0x71
+#define RTC_NMI_DISABLE (1<<8)
+#define RTC_NMI_ENABLE 0
+#define RTC_SEC 0x00
+#define RTC_MIN 0x02
+#define RTC_HOUR 0x04
+#define RTC_DAY 0x07
+#define RTC_MONTH 0x08
+#define RTC_YEAR 0x09
+#define RTC_STATUS_A 0x0a
+#define RTC_UIP (1<<7)
+
+/* RTC wall time offset at monotonic time base. */
+static __u64 rtc_epochoffset;
+
+/*
+ * TSC clock specific.
+ */
+
+/* Base time values at the last call to tscclock_monotonic(). */
+static __u64 time_base;
+static __u64 tsc_base;
+
+/* Multiplier for converting TSC ticks to nsecs. (0.32) fixed point. */
+static __u32 tsc_mult;
+
+/*
+ * Multiplier for converting nsecs to PIT ticks. (1.32) fixed point.
+ *
+ * Calculated as:
+ *
+ * f = NSEC_PER_SEC / TIMER_HZ (0.31) fixed point.
+ * pit_mult = 1 / f (1.32) fixed point.
+ */
+static const __u32 pit_mult =
+ (1ULL << 63) / ((NSEC_PER_SEC << 31) / TIMER_HZ);
+
+
+/*
+ * Read the current i8254 channel 0 tick count.
+ */
+static unsigned int i8254_gettick(void)
+{
+ __u16 rdval;
+
+ outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
+ rdval = inb(TIMER_CNTR);
+ rdval |= (inb(TIMER_CNTR) << 8);
+ return rdval;
+}
+
+/*
+ * Delay for approximately n microseconds using the i8254 channel 0 counter.
+ * Timer must be programmed appropriately before calling this function.
+ */
+static void i8254_delay(unsigned int n)
+{
+ unsigned int cur_tick, initial_tick;
+ int remaining;
+ const unsigned long timer_rval = TIMER_HZ / 100;
+
+ initial_tick = i8254_gettick();
+
+ remaining = (unsigned long long) n * TIMER_HZ / 1000000;
+
+ while (remaining > 1) {
+ cur_tick = i8254_gettick();
+ if (cur_tick > initial_tick)
+ remaining -= timer_rval - (cur_tick - initial_tick);
+ else
+ remaining -= initial_tick - cur_tick;
+ initial_tick = cur_tick;
+ }
+}
+
+/*
+ * Read a RTC register. Due to PC platform braindead-ness also disables NMI.
+ */
+static inline __u8 rtc_read(__u8 reg)
+{
+ outb(RTC_COMMAND, reg | RTC_NMI_DISABLE);
+ return inb(RTC_DATA);
+}
+
+/*
+ * Return current RTC time. Note that due to waiting for the update cycle to
+ * complete, this call may take some time.
+ */
+static __u64 rtc_gettimeofday(void)
+{
+ struct bmk_clock_ymdhms dt;
+ unsigned long flags;
+
+ flags = ukplat_lcpu_save_irqf();
+
+ /*
+ * If RTC_UIP is down, we have at least 244us to obtain a
+ * consistent reading before an update can occur.
+ */
+ while (rtc_read(RTC_STATUS_A) & RTC_UIP)
+ continue;
+
+ dt.dt_sec = bcdtobin(rtc_read(RTC_SEC));
+ dt.dt_min = bcdtobin(rtc_read(RTC_MIN));
+ dt.dt_hour = bcdtobin(rtc_read(RTC_HOUR));
+ dt.dt_day = bcdtobin(rtc_read(RTC_DAY));
+ dt.dt_mon = bcdtobin(rtc_read(RTC_MONTH));
+ dt.dt_year = bcdtobin(rtc_read(RTC_YEAR)) + 2000;
+
+ ukplat_lcpu_restore_irqf(flags);
+
+ return ukarch_time_sec_to_nsec(clock_ymdhms_to_secs(&dt));
+}
+
+/*
+ * Beturn monotonic time using TSC clock.
+ */
+__u64 tscclock_monotonic(void)
+{
+ __u64 tsc_now, tsc_delta;
+
+ /*
+ * Update time_base (monotonic time) and tsc_base (TSC time).
+ */
+ tsc_now = rdtsc();
+ tsc_delta = tsc_now - tsc_base;
+ time_base += mul64_32(tsc_delta, tsc_mult);
+ tsc_base = tsc_now;
+
+ return time_base;
+}
+
+/*
+ * Calibrate TSC and initialise TSC clock.
+ */
+int tscclock_init(void)
+{
+ __u64 tsc_freq, rtc_boot;
+
+ /* Initialise i8254 timer channel 0 to mode 2 at 100 Hz */
+ outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+ outb(TIMER_CNTR, (TIMER_HZ / 100) & 0xff);
+ outb(TIMER_CNTR, (TIMER_HZ / 100) >> 8);
+
+ /*
+ * Read RTC "time at boot". This must be done just before tsc_base is
+ * initialised in order to get a correct offset below.
+ */
+ rtc_boot = rtc_gettimeofday();
+
+ /*
+ * Calculate TSC frequency by calibrating against an 0.1s delay
+ * using the i8254 timer.
+ */
Wow, this is adds a 100ms boot delay to the Unikernels on KVM. Can you
put an TODO comment for revisiting this later? Maybe we can find a
different method to get the correct value for the TSC frequency.
+ tsc_base = rdtsc();
+ i8254_delay(100000);
+ tsc_freq = (rdtsc() - tsc_base) * 10;
+ uk_printd(DLVL_INFO,
+ "Clock source: TSC, frequency estimate is %llu Hz\n",
+ (unsigned long long) tsc_freq); //TODO
+
+ /*
+ * Calculate TSC scaling multiplier.
+ *
+ * (0.32) tsc_mult = NSEC_PER_SEC (32.32) / tsc_freq (32.0)
+ */
+ tsc_mult = (NSEC_PER_SEC << 32) / tsc_freq;
+
+ /*
+ * Monotonic time begins at tsc_base (first read of TSC before
+ * calibration).
+ */
+ time_base = mul64_32(tsc_base, tsc_mult);
+
+ /*
+ * Compute RTC epoch offset by subtracting monotonic time_base from RTC
+ * time at boot.
+ */
+ rtc_epochoffset = rtc_boot - time_base;
+
+ /*
+ * Initialise i8254 timer channel 0 to mode 4 (one shot).
+ */
+ outb(TIMER_MODE, TIMER_SEL0 | TIMER_ONESHOT | TIMER_16BIT);
+
+ return 0;
+}
+
+/*
+ * Return epoch offset (wall time offset to monotonic clock start).
+ */
+__u64 tscclock_epochoffset(void)
+{
+ return rtc_epochoffset;
+}
+
+/*
+ * Minimum delta to sleep using PIT. Programming seems to have an overhead of
+ * 3-4us, but play it safe here.
+ */
+#define PIT_MIN_DELTA 16
+
+/*
+ * Returns early if any interrupts are serviced, or if the requested delay is
+ * too short. Must be called with interrupts disabled, will enable interrupts
+ * "atomically" during idle loop.
+ */
+static void tscclock_cpu_block(__u64 until)
+{
+ __u64 now, delta_ns;
+ __u64 delta_ticks;
+ unsigned int ticks;
+
+ UK_ASSERT(ukplat_lcpu_irqs_disabled());
+
+ now = ukplat_monotonic_clock();
+
+ /*
+ * Compute delta in PIT ticks. Return if it is less than minimum safe
+ * amount of ticks. Essentially this will cause us to spin until
+ * the timeout.
+ */
+ delta_ns = until - now;
+ delta_ticks = mul64_32(delta_ns, pit_mult);
+ if (delta_ticks < PIT_MIN_DELTA) {
+ /*
+ * Since we are "spinning", quickly enable interrupts in
+ * the hopes that we might get new work and can do something
+ * else than spin.
+ */
+ ukplat_lcpu_enable_irq();
+ nop(); /* ints are enabled 1 instr after sti */
+ ukplat_lcpu_disable_irq();
+ return;
+ }
+
+ /*
+ * Program the timer to interrupt the CPU after the delay has expired.
+ * Maximum timer delay is 65535 ticks.
+ */
+ if (delta_ticks > 65535)
+ ticks = 65535;
+ else
+ ticks = delta_ticks;
+
+ /*
+ * Note that according to the Intel 82C54 datasheet, p12 the
+ * interrupt is actually delivered in N + 1 ticks.
+ */
+ ticks -= 1;
+ outb(TIMER_CNTR, ticks & 0xff);
+ outb(TIMER_CNTR, ticks >> 8);
+
+ /*
+ * Wait for any interrupt. If we got an interrupt then
+ * just return into the scheduler which will check if there is
+ * work to do and send us back here if not.
+ *
+ * TODO: It would be more efficient for longer sleeps to be
+ * able to distinguish if the interrupt was the PIT interrupt
+ * and no other, but this will do for now.
+ */
+ ukplat_lcpu_halt_irq();
+}
+
+long nontsc_interrupt_assert;
+
+void time_block_until(__snsec until)
+{
+ volatile long *pnontsc_interrupt_assert = &nontsc_interrupt_assert;
+
+ while ((__snsec) ukplat_monotonic_clock() < until) {
+ tscclock_cpu_block(until);
+
+ /* who triggered the interrupt? */
+ if (*pnontsc_interrupt_assert) {
+ /* it was another device, stop blocking */
+ nontsc_interrupt_assert = 0;
+ break;
+ }
+ /* it was us */
+ }
+}
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