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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Minios-devel] [UNIKRAFT PATCH v3 8/8] plat/kvm: Add KVM (x86_64) timer support
Changes since v2:
- Few more comments
- rename nontsc_interrupt_assert to more understandable
understandable
- use atomics to signal scheduler to exit halting loop
- fix comment indentation
-- >8 --
From 3e8e3b8a4be08b26b58ec3bbbe19f31c1d55e0d2 Mon Sep 17 00:00:00 2001
From: Costin Lupu <costin.lupu@xxxxxxxxx>
Date: Tue, 12 Jun 2018 17:15:55 +0200
Subject: [UNIKRAFT PATCH v3 8/8] plat/kvm: Add KVM (x86_64) timer support
We are using TSC clock as main timer on KVM.
Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
---
plat/kvm/Config.uk | 1 +
plat/kvm/Makefile.uk | 2 +
plat/kvm/include/kvm/tscclock.h | 42 ++++
plat/kvm/irq.c | 21 ++
plat/kvm/time.c | 65 ++++++
plat/kvm/tscclock.c | 360 ++++++++++++++++++++++++++++++++
6 files changed, 491 insertions(+)
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/Config.uk b/plat/kvm/Config.uk
index 449c381..622c4eb 100644
--- a/plat/kvm/Config.uk
+++ b/plat/kvm/Config.uk
@@ -4,6 +4,7 @@ menuconfig PLAT_KVM
depends on (ARCH_X86_64)
select LIBUKDEBUG
select LIBUKALLOC
+ select LIBUKTIMECONV
select LIBNOLIBC if !HAVE_LIBC
help
Create a Unikraft image that runs as a KVM guest
diff --git a/plat/kvm/Makefile.uk b/plat/kvm/Makefile.uk
index 46258ff..dcfa517 100644
--- a/plat/kvm/Makefile.uk
+++ b/plat/kvm/Makefile.uk
@@ -34,4 +34,6 @@ 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 += $(UK_PLAT_COMMON_BASE)/lcpu.c|common
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__
+
+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 b3d8aaa..f482942 100644
--- a/plat/kvm/irq.c
+++ b/plat/kvm/irq.c
@@ -34,6 +34,7 @@
#include <kvm/intctrl.h>
#include <uk/assert.h>
#include <errno.h>
+#include <uk/arch/atomic.h>
static struct uk_alloc *allocator;
@@ -71,12 +72,32 @@ int ukplat_irq_register(unsigned long irq,
irq_handler_func_t func, void *arg)
return 0;
}
+/*
+ * TODO: This is a temporary solution used to identify non TSC clock
+ * interrupts in order to stop waiting for interrupts with deadline.
+ */
+extern long sched_have_pending_events;
+
void _ukplat_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)
+ /* IRQ 0 is reserved for a timer, responsible to
+ * wake up cpu from halt, so it can check if
+ * it has something to do. Effectively it is OS ticks.
+ *
+ * If interrupt comes not from the timer, the
+ * chances are some work have just
+ * arrived. Let's kick the scheduler out of
+ * the halting loop, and let it take care of
+ * that work.
+ */
+ ukarch_test_and_set_bit(0, &sched_have_pending_events);
+
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..1fb48bf
--- /dev/null
+++ b/plat/kvm/time.c
@@ -0,0 +1,65 @@
+/* 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 <uk/plat/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;
+
+ rc = ukplat_irq_register(0, timer_handler, NULL);
+ if (rc < 0)
+ UK_CRASH("Failed to register timer interrupt handler\n");
+
+ rc = tscclock_init();
+ if (rc < 0)
+ UK_CRASH("Failed to initialize TSCCLOCK\n");
+}
diff --git a/plat/kvm/tscclock.c b/plat/kvm/tscclock.c
new file mode 100644
index 0000000..8961659
--- /dev/null
+++ b/plat/kvm/tscclock.c
@@ -0,0 +1,360 @@
+/* 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 <uk/timeconv.h>
+#include <uk/print.h>
+#include <uk/assert.h>
+#include <uk/arch/atomic.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 uktimeconv_bmkclock 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 = uktimeconv_bcdtobin(rtc_read(RTC_SEC));
+ dt.dt_min = uktimeconv_bcdtobin(rtc_read(RTC_MIN));
+ dt.dt_hour = uktimeconv_bcdtobin(rtc_read(RTC_HOUR));
+ dt.dt_day = uktimeconv_bcdtobin(rtc_read(RTC_DAY));
+ dt.dt_mon = uktimeconv_bcdtobin(rtc_read(RTC_MONTH));
+ dt.dt_year = uktimeconv_bcdtobin(rtc_read(RTC_YEAR)) + 2000;
+
+ ukplat_lcpu_restore_irqf(flags);
+
+ return uktimeconv_bmkclock_to_nsec(&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.
+ * TODO: Find a more elegant solution that does not require us to
+ * to delay the boot for 100ms. Does KVM provides us a pre-calculated
+ * TSC value?
+ */
+ 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);
+
+ /*
+ * 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.
+ *
+ * This function must be called only from the scheduler. It will screw
+ * your system if you do otherwise. And, there is no reason you
+ * actually want to use it anywhere else. THIS IS NOT A YIELD or any
+ * kind of mutex_lock. It will simply halt the cpu, not allowing any
+ * other thread to execute.
+ */
+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 (this func is called _ONLY_ from
+ * a scheduler, see the note above) which will check if there
+ * is work to do and call us again 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 sched_have_pending_events;
+
+void time_block_until(__snsec until)
+{
+ while ((__snsec) ukplat_monotonic_clock() < until) {
+ tscclock_cpu_block(until);
+
+ if (ukarch_test_and_clr_bit(0, &sched_have_pending_events))
+ break;
+ }
+}
--
2.17.0
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