The patch titled
lguest: use TSC
has been removed from the -mm tree. Its filename was
lguest-the-host-code-use-tsc.patch
This patch was dropped because it was folded into lguest-the-host-code.patch
------------------------------------------------------
Subject: lguest: use TSC
From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
James: Add rudimentary TSC-based clocksource support (based on Rusty's
original patch).
Rusty: Add rudimentary code to handle TSC changing. We can use the native
sched_clock again, we just have to tell it the TSC speed (get_cpu_khz).
(Note on benchmarks: Linux only sets the clock to the nearest second, so
expect it to be up to up to 1000000000 ns out. But the narrowness of the max
- min range indicates consistency.)
Before:
Approximate accuracy of clock: 827460500 (819802000 - 834640500)
After:
Approximate accuracy of clock: 326354500 (326257000 - 327937500)
Signed-off-by: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/kernel/tsc.c | 1 +
drivers/lguest/core.c | 8 ++++++++
drivers/lguest/lg.h | 1 +
drivers/lguest/lguest.c | 38 +++++++++++++++++++++++++++++++-------
include/linux/lguest.h | 2 ++
5 files changed, 43 insertions(+), 7 deletions(-)
diff -puN arch/i386/kernel/tsc.c~lguest-the-host-code-use-tsc arch/i386/kernel/tsc.c
--- a/arch/i386/kernel/tsc.c~lguest-the-host-code-use-tsc
+++ a/arch/i386/kernel/tsc.c
@@ -26,6 +26,7 @@ static int tsc_enabled;
* an extra value to store the TSC freq
*/
unsigned int tsc_khz;
+EXPORT_SYMBOL_GPL(tsc_khz);
int tsc_disable;
diff -puN drivers/lguest/core.c~lguest-the-host-code-use-tsc drivers/lguest/core.c
--- a/drivers/lguest/core.c~lguest-the-host-code-use-tsc
+++ a/drivers/lguest/core.c
@@ -332,6 +332,14 @@ int run_guest(struct lguest *lg, unsigne
continue;
}
+ /* If the Guest hasn't been told the clock multiplier to use or
+ * it's changed, we update it here. */
+ if (unlikely(lg->tsc_khz != tsc_khz) && lg->lguest_data) {
+ lg->tsc_khz = tsc_khz;
+ if (put_user(lg->tsc_khz, &lg->lguest_data->tsc_khz))
+ return -EFAULT;
+ }
+
local_irq_disable();
/* Even if *we* don't want FPU trap, guest might... */
diff -puN drivers/lguest/lg.h~lguest-the-host-code-use-tsc drivers/lguest/lg.h
--- a/drivers/lguest/lg.h~lguest-the-host-code-use-tsc
+++ a/drivers/lguest/lg.h
@@ -160,6 +160,7 @@ struct lguest
unsigned long pending_key; /* address they're sending to */
unsigned int stack_pages;
+ u32 tsc_khz;
struct lguest_dma_info dma[LGUEST_MAX_DMA];
diff -puN drivers/lguest/lguest.c~lguest-the-host-code-use-tsc drivers/lguest/lguest.c
--- a/drivers/lguest/lguest.c~lguest-the-host-code-use-tsc
+++ a/drivers/lguest/lguest.c
@@ -25,6 +25,7 @@
#include <linux/screen_info.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
+#include <linux/clocksource.h>
#include <linux/lguest.h>
#include <linux/lguest_launcher.h>
#include <linux/lguest_bus.h>
@@ -37,6 +38,7 @@
#include <asm/e820.h>
#include <asm/mce.h>
#include <asm/io.h>
+#include <asm/sched-clock.h>
/* Declarations for definitions in lguest_guest.S */
extern char lguest_noirq_start[], lguest_noirq_end[];
@@ -209,8 +211,8 @@ static void lguest_cpuid(unsigned int *e
case 1: /* Basic feature request. */
/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
*ecx &= 0x00002201;
- /* Similarly: SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, FPU. */
- *edx &= 0x07808101;
+ /* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU. */
+ *edx &= 0x07808111;
/* Host wants to know when we flush kernel pages: set PGE. */
*edx |= 0x00002000;
break;
@@ -345,24 +347,46 @@ static unsigned long lguest_get_wallcloc
return hcall(LHCALL_GET_WALLCLOCK, 0, 0, 0);
}
+/* This is what we tell the kernel is our clocksource. It's the normal "Time
+ * Stamp Counter": the Host tells us what speed it's going at. */
+static struct clocksource lguest_clock = {
+ .name = "lguest",
+ .rating = 400,
+ .read = native_read_tsc,
+ .mask = CLOCKSOURCE_MASK(64),
+ .mult = 0, /* to be set */
+ .shift = 22,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
static void lguest_time_irq(unsigned int irq, struct irq_desc *desc)
{
+ /* Check in case host TSC has changed rate. */
+ if (unlikely(tsc_khz != lguest_data.tsc_khz)) {
+ tsc_khz = lguest_data.tsc_khz;
+ lguest_clock.mult = clocksource_khz2mult(tsc_khz, 22);
+ __get_cpu_var(sc_data).cyc2ns_scale
+ = (1000000 << CYC2NS_SCALE_FACTOR) / tsc_khz;
+ }
do_timer(hcall(LHCALL_TIMER_READ, 0, 0, 0));
update_process_times(user_mode_vm(get_irq_regs()));
}
-static u64 sched_clock_base;
static void lguest_time_init(void)
{
set_irq_handler(0, lguest_time_irq);
+
+ lguest_clock.mult = clocksource_khz2mult(tsc_khz, 22);
+ clocksource_register(&lguest_clock);
+
hcall(LHCALL_TIMER_READ, 0, 0, 0);
- sched_clock_base = jiffies_64;
enable_lguest_irq(0);
}
-static unsigned long long lguest_sched_clock(void)
+static unsigned long lguest_get_cpu_khz(void)
{
- return (jiffies_64 - sched_clock_base) * (1000000000 / HZ);
+ /* The Host tells us the TSC speed */
+ return lguest_data.tsc_khz;
}
static void lguest_load_esp0(struct tss_struct *tss,
@@ -502,7 +526,7 @@ __init void lguest_init(void *boot)
paravirt_ops.time_init = lguest_time_init;
paravirt_ops.set_lazy_mode = lguest_lazy_mode;
paravirt_ops.wbinvd = lguest_wbinvd;
- paravirt_ops.sched_clock = lguest_sched_clock;
+ paravirt_ops.get_cpu_khz = lguest_get_cpu_khz;
hcall(LHCALL_LGUEST_INIT, __pa(&lguest_data), 0, 0);
diff -puN include/linux/lguest.h~lguest-the-host-code-use-tsc include/linux/lguest.h
--- a/include/linux/lguest.h~lguest-the-host-code-use-tsc
+++ a/include/linux/lguest.h
@@ -70,6 +70,8 @@ struct lguest_data
unsigned long reserve_mem;
/* ID of this guest (used by network driver to set ethernet address) */
u16 guestid;
+ /* KHz for the TSC clock. */
+ u32 tsc_khz;
/* Fields initialized by the guest at boot: */
/* Instruction range to suppress interrupts even if enabled */
_
Patches currently in -mm which might be from rusty@xxxxxxxxxxxxxxx are
git-kbuild.patch
paravirt-helper-to-disable-all-io-space.patch
paravirt-helper-to-disable-all-io-space-fix.patch
xen-disable-all-non-virtual-devices.patch
mm-clean-up-and-kernelify-shrinker-registration.patch
use-menuconfig-objects-ii-module-menu.patch
fix-stop_machine_run-problem-with-naughty-real-time-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process.patch
cpu-hotplug-fix-ksoftirqd-termination-on-cpu-hotplug-with-naughty-realtime-process-fix.patch
lguest-export-symbols-for-lguest-as-a-module.patch
lguest-the-guest-code.patch
lguest-the-host-code.patch
lguest-the-host-code-use-tsc.patch
lguest-the-host-code-use-hrtimers.patch
lguest-the-host-code-update-for-mm-simplify-boot_params.patch
lguest-the-asm-offsets.patch
lguest-the-makefile-and-kconfig.patch
lguest-the-makefile-and-kconfig-tidyups.patch
lguest-the-console-driver.patch
lguest-the-console-driver-tidyups.patch
lguest-the-net-driver.patch
lguest-the-net-driver-tidyups.patch
lguest-the-net-driver-tidyups-update.patch
lguest-the-net-driver-include-fix.patch
lguest-the-block-driver.patch
lguest-the-block-driver-tidyups.patch
lguest-the-block-driver-tidyups-update.patch
lguest-the-documentation-example-launcher.patch
lguest-the-documentation-example-launcher-example-launcher-fix.patch
lguest-dont-signal-like-crazy-use-lhreq_break-command-doc.patch
lguest-documentation-infrastructure-and-chapter-i.patch
mm-clean-up-and-kernelify-shrinker-registration-reiser4.patch
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