[RFC 1/3] hvc_console: rework setup to replace irq functions with callbacks
This patch tries to change hvc_console to not use request_irq/free_irq if
the backend does not use irqs. This allows virtio_console to use hvc_console
without having a linker reference to request_irq/free_irq.
The irq specific code is moved to hvc_irq.c and selected by the drivers that
use irqs (System p, System i, XEN).
I replaced irq with the opaque name data. The request_irq and free_irq
calls are replaced with notifier_add and notifier_del. I have also changed
the code a bit to call the notifier_add and notifier_del inside the spinlock
area as the callbacks are found via hp-ops.
Feedback is appreciated.
Signed-off-by: Christian Borntraeger [EMAIL PROTECTED]
---
drivers/char/Kconfig |8
drivers/char/Makefile |1
drivers/char/hvc_console.c | 80
++---
drivers/char/hvc_console.h | 34 ---
drivers/char/hvc_irq.c | 37
drivers/char/hvc_iseries.c |2 +
drivers/char/hvc_vio.c |2 +
drivers/char/hvc_xen.c |2 +
8 files changed, 100 insertions(+), 66 deletions(-)
Index: kvm/drivers/char/Kconfig
===
--- kvm.orig/drivers/char/Kconfig
+++ kvm/drivers/char/Kconfig
@@ -588,11 +588,17 @@ config HVC_DRIVER
It will automatically be selected if one of the back-end console
drivers
is selected.
+config HVC_IRQ
+ bool
+ help
+ Infrastructure for using the IRQ code for HVC console.
+ It will automatically be selected by the drivers that need it.
config HVC_CONSOLE
bool pSeries Hypervisor Virtual Console support
depends on PPC_PSERIES
select HVC_DRIVER
+ select HVC_IRQ
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
@@ -603,6 +609,7 @@ config HVC_ISERIES
depends on PPC_ISERIES
default y
select HVC_DRIVER
+ select HVC_IRQ
help
iSeries machines support a hypervisor virtual console.
@@ -624,6 +631,7 @@ config HVC_XEN
bool Xen Hypervisor Console support
depends on XEN
select HVC_DRIVER
+ select HVC_IRQ
default y
help
Xen virtual console device driver
Index: kvm/drivers/char/Makefile
===
--- kvm.orig/drivers/char/Makefile
+++ kvm/drivers/char/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_HVC_ISERIES) += hvc_iseries
obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o
obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
+obj-$(CONFIG_HVC_IRQ) += hvc_irq.o
obj-$(CONFIG_HVC_XEN) += hvc_xen.o
obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
Index: kvm/drivers/char/hvc_console.c
===
--- kvm.orig/drivers/char/hvc_console.c
+++ kvm/drivers/char/hvc_console.c
@@ -75,23 +75,6 @@ static int hvc_init(void);
static int sysrq_pressed;
#endif
-struct hvc_struct {
- spinlock_t lock;
- int index;
- struct tty_struct *tty;
- unsigned int count;
- int do_wakeup;
- char *outbuf;
- int outbuf_size;
- int n_outbuf;
- uint32_t vtermno;
- struct hv_ops *ops;
- int irq_requested;
- int irq;
- struct list_head next;
- struct kref kref; /* ref count hvc_struct lifetime */
-};
-
/* dynamic list of hvc_struct instances */
static LIST_HEAD(hvc_structs);
@@ -300,26 +283,12 @@ int hvc_instantiate(uint32_t vtermno, in
}
/* Wake the sleeping khvcd */
-static void hvc_kick(void)
+void hvc_kick(void)
{
hvc_kicked = 1;
wake_up_process(hvc_task);
}
-static int hvc_poll(struct hvc_struct *hp);
-
-/*
- * NOTE: This API isn't used if the console adapter doesn't support
interrupts.
- * In this case the console is poll driven.
- */
-static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
-{
- /* if hvc_poll request a repoll, then kick the hvcd thread */
- if (hvc_poll(dev_instance))
- hvc_kick();
- return IRQ_HANDLED;
-}
-
static void hvc_unthrottle(struct tty_struct *tty)
{
hvc_kick();
@@ -333,7 +302,6 @@ static int hvc_open(struct tty_struct *t
{
struct hvc_struct *hp;
unsigned long flags;
- int irq = 0;
int rc = 0;
/* Auto increments kref reference if found. */
@@ -352,18 +320,15 @@ static int hvc_open(struct tty_struct *t
tty-low_latency = 1; /* Makes flushes to ldisc synchronous. */
hp-tty = tty;
- /* Save for request_irq outside of spin_lock. */
- irq = hp-irq;
- if (irq)
- hp-irq_requested = 1;
+
+ if (hp-ops-notifier_add)
+ rc = hp-ops-notifier_add(hp, hp-data);
[RFC 1/3] hvc_console: rework setup to replace irq functions with callbacks (not word wrapped)
This patch tries to change hvc_console to not use request_irq/free_irq if
the backend does not use irqs. This allows virtio_console to use hvc_console
without having a linker reference to request_irq/free_irq.
The irq specific code is moved to hvc_irq.c and selected by the drivers that
use irqs (System p, System i, XEN).
I replaced irq with the opaque name data. The request_irq and free_irq
calls are replaced with notifier_add and notifier_del. I have also changed
the code a bit to call the notifier_add and notifier_del inside the spinlock
area as the callbacks are found via hp-ops.
Feedback is appreciated.
Signed-off-by: Christian Borntraeger [EMAIL PROTECTED]
CC: Rusty Russell [EMAIL PROTECTED]
CC: Jeremy Fitzhardinge [EMAIL PROTECTED]
CC: LKML [EMAIL PROTECTED]
CC: Virtualization Mailing List [EMAIL PROTECTED]
CC: Linux PPC devel [EMAIL PROTECTED]
---
drivers/char/Kconfig |8
drivers/char/Makefile |1
drivers/char/hvc_console.c | 80 ++---
drivers/char/hvc_console.h | 34 ---
drivers/char/hvc_irq.c | 37
drivers/char/hvc_iseries.c |2 +
drivers/char/hvc_vio.c |2 +
drivers/char/hvc_xen.c |2 +
8 files changed, 100 insertions(+), 66 deletions(-)
Index: kvm/drivers/char/Kconfig
===
--- kvm.orig/drivers/char/Kconfig
+++ kvm/drivers/char/Kconfig
@@ -588,11 +588,17 @@ config HVC_DRIVER
It will automatically be selected if one of the back-end console
drivers
is selected.
+config HVC_IRQ
+ bool
+ help
+ Infrastructure for using the IRQ code for HVC console.
+ It will automatically be selected by the drivers that need it.
config HVC_CONSOLE
bool pSeries Hypervisor Virtual Console support
depends on PPC_PSERIES
select HVC_DRIVER
+ select HVC_IRQ
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
@@ -603,6 +609,7 @@ config HVC_ISERIES
depends on PPC_ISERIES
default y
select HVC_DRIVER
+ select HVC_IRQ
help
iSeries machines support a hypervisor virtual console.
@@ -624,6 +631,7 @@ config HVC_XEN
bool Xen Hypervisor Console support
depends on XEN
select HVC_DRIVER
+ select HVC_IRQ
default y
help
Xen virtual console device driver
Index: kvm/drivers/char/Makefile
===
--- kvm.orig/drivers/char/Makefile
+++ kvm/drivers/char/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_HVC_ISERIES) += hvc_iseries
obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o
obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
+obj-$(CONFIG_HVC_IRQ) += hvc_irq.o
obj-$(CONFIG_HVC_XEN) += hvc_xen.o
obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
Index: kvm/drivers/char/hvc_console.c
===
--- kvm.orig/drivers/char/hvc_console.c
+++ kvm/drivers/char/hvc_console.c
@@ -75,23 +75,6 @@ static int hvc_init(void);
static int sysrq_pressed;
#endif
-struct hvc_struct {
- spinlock_t lock;
- int index;
- struct tty_struct *tty;
- unsigned int count;
- int do_wakeup;
- char *outbuf;
- int outbuf_size;
- int n_outbuf;
- uint32_t vtermno;
- struct hv_ops *ops;
- int irq_requested;
- int irq;
- struct list_head next;
- struct kref kref; /* ref count hvc_struct lifetime */
-};
-
/* dynamic list of hvc_struct instances */
static LIST_HEAD(hvc_structs);
@@ -300,26 +283,12 @@ int hvc_instantiate(uint32_t vtermno, in
}
/* Wake the sleeping khvcd */
-static void hvc_kick(void)
+void hvc_kick(void)
{
hvc_kicked = 1;
wake_up_process(hvc_task);
}
-static int hvc_poll(struct hvc_struct *hp);
-
-/*
- * NOTE: This API isn't used if the console adapter doesn't support interrupts.
- * In this case the console is poll driven.
- */
-static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
-{
- /* if hvc_poll request a repoll, then kick the hvcd thread */
- if (hvc_poll(dev_instance))
- hvc_kick();
- return IRQ_HANDLED;
-}
-
static void hvc_unthrottle(struct tty_struct *tty)
{
hvc_kick();
@@ -333,7 +302,6 @@ static int hvc_open(struct tty_struct *t
{
struct hvc_struct *hp;
unsigned long flags;
- int irq = 0;
int rc = 0;
/* Auto increments kref reference if found. */
@@ -352,18 +320,15 @@ static int hvc_open(struct tty_struct *t
tty-low_latency = 1; /* Makes flushes to ldisc synchronous. */
hp-tty = tty;
- /* Save for request_irq
[RFC 2/3] virtio_console: use virtqueue notification for hvc_console
This patch exploits the new notifier callbacks of the hvc_console. We can
use the virtio callbacks instead of the polling code.
I also added a small Kconfig change that allows the user to specify the
virtio console in menuconfig.
Signed-off-by: Christian Borntraeger [EMAIL PROTECTED]
---
drivers/char/Kconfig |6 +-
drivers/char/virtio_console.c | 27 +--
2 files changed, 30 insertions(+), 3 deletions(-)
Index: kvm/drivers/char/Kconfig
===
--- kvm.orig/drivers/char/Kconfig
+++ kvm/drivers/char/Kconfig
@@ -637,8 +637,12 @@ config HVC_XEN
Xen virtual console device driver
config VIRTIO_CONSOLE
- bool
+ bool Virtio console
+ depends on VIRTIO
select HVC_DRIVER
+ help
+ Virtio console for use with lguest and other hypervisors.
+
config HVCS
tristate IBM Hypervisor Virtual Console Server support
Index: kvm/drivers/char/virtio_console.c
===
--- kvm.orig/drivers/char/virtio_console.c
+++ kvm/drivers/char/virtio_console.c
@@ -46,6 +46,9 @@ static char *in, *inbuf;
/* The operations for our console. */
static struct hv_ops virtio_cons;
+/* The hvc device */
+struct hvc_struct *hvc;
+
/*D:310 The put_chars() callback is pretty straightforward.
*
* We turn the characters into a scatter-gather list, add it to the output
@@ -134,6 +137,25 @@ int __init virtio_cons_early_init(int (*
return hvc_instantiate(0, 0, virtio_cons);
}
+/*
+ * we support only one console, the hvc struct is a global var
+ * There is no need to do anything
+ */
+static int notifier_add_vio(struct hvc_struct *hp, int data)
+{
+ return 0;
+}
+
+static void notifier_del_vio(struct hvc_struct *hp, int data)
+{
+}
+
+static void hvc_handle_input(struct virtqueue *vq)
+{
+ if (hvc_poll(hvc))
+ hvc_kick();
+}
+
/*D:370 Once we're further in boot, we get probed like any other virtio
device.
* At this stage we set up the output virtqueue.
*
@@ -144,7 +166,6 @@ int __init virtio_cons_early_init(int (*
static int __devinit virtcons_probe(struct virtio_device *dev)
{
int err;
- struct hvc_struct *hvc;
vdev = dev;
@@ -158,7 +179,7 @@ static int __devinit virtcons_probe(stru
/* Find the input queue. */
/* FIXME: This is why we want to wean off hvc: we do nothing
* when input comes in. */
- in_vq = vdev-config-find_vq(vdev, 0, NULL);
+ in_vq = vdev-config-find_vq(vdev, 0, hvc_handle_input);
if (IS_ERR(in_vq)) {
err = PTR_ERR(in_vq);
goto free;
@@ -173,6 +194,8 @@ static int __devinit virtcons_probe(stru
/* Start using the new console output. */
virtio_cons.get_chars = get_chars;
virtio_cons.put_chars = put_chars;
+ virtio_cons.notifier_add = notifier_add_vio;
+ virtio_cons.notifier_del = notifier_del_vio;
/* The first argument of hvc_alloc() is the virtual console number, so
* we use zero. The second argument is the interrupt number; we
___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/virtualization
[PATCH 1/5] Add structs and functions for paravirt clocksource.
This patch adds structs for the paravirt clocksource ABI
used by both xen and kvm (pvclock-abi.h).
It also adds some helper functions to read system time and
wall clock time from a paravirtual clocksource (pvclock.[ch]).
They are based on the xen code. They are enabled using
CONFIG_PARAVIRT_CLOCK.
Subsequent patches of this series will put the code in use.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/Kconfig |4 +
arch/x86/kernel/Makefile |1 +
arch/x86/kernel/pvclock.c | 141 +
include/asm-x86/pvclock-abi.h | 42
include/asm-x86/pvclock.h | 13
5 files changed, 201 insertions(+), 0 deletions(-)
create mode 100644 arch/x86/kernel/pvclock.c
create mode 100644 include/asm-x86/pvclock-abi.h
create mode 100644 include/asm-x86/pvclock.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index dcbec34..5fc46c1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -410,6 +410,10 @@ config PARAVIRT
over full virtualization. However, when run without a hypervisor
the kernel is theoretically slower and slightly larger.
+config PARAVIRT_CLOCK
+ bool
+ default n
+
endif
config MEMTEST_BOOTPARAM
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5e618c3..77807d4 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_VMI) += vmi_32.o vmiclock_32.o
obj-$(CONFIG_KVM_GUEST)+= kvm.o
obj-$(CONFIG_KVM_CLOCK)+= kvmclock.o
obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o
+obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
new file mode 100644
index 000..05fbe9a
--- /dev/null
+++ b/arch/x86/kernel/pvclock.c
@@ -0,0 +1,141 @@
+/* paravirtual clock -- common code used by kvm/xen
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#include linux/kernel.h
+#include linux/percpu.h
+#include asm/pvclock.h
+
+/*
+ * These are perodically updated
+ *xen: magic shared_info page
+ *kvm: gpa registered via msr
+ * and then copied here.
+ */
+struct pvclock_shadow_time {
+ u64 tsc_timestamp; /* TSC at last update of time vals. */
+ u64 system_timestamp; /* Time, in nanosecs, since boot.*/
+ u32 tsc_to_nsec_mul;
+ int tsc_shift;
+ u32 version;
+};
+
+/*
+ * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
+ * yielding a 64-bit result.
+ */
+static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
+{
+ u64 product;
+#ifdef __i386__
+ u32 tmp1, tmp2;
+#endif
+
+ if (shift 0)
+ delta = -shift;
+ else
+ delta = shift;
+
+#ifdef __i386__
+ __asm__ (
+ mul %5 ;
+ mov %4,%%eax ;
+ mov %%edx,%4 ;
+ mul %5 ;
+ xor %5,%5;
+ add %4,%%eax ;
+ adc %5,%%edx ;
+ : =A (product), =r (tmp1), =r (tmp2)
+ : a ((u32)delta), 1 ((u32)(delta 32)), 2 (mul_frac) );
+#elif __x86_64__
+ __asm__ (
+ mul %%rdx ; shrd $32,%%rdx,%%rax
+ : =a (product) : 0 (delta), d ((u64)mul_frac) );
+#else
+#error implement me!
+#endif
+
+ return product;
+}
+
+static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
+{
+ u64 delta = native_read_tsc() - shadow-tsc_timestamp;
+ return scale_delta(delta, shadow-tsc_to_nsec_mul, shadow-tsc_shift);
+}
+
+/*
+ * Reads a consistent set of time-base values from hypervisor,
+ * into a shadow data area.
+ */
+static unsigned pvclock_get_time_values(struct pvclock_shadow_time *dst,
+ struct pvclock_vcpu_time_info *src)
+{
+ do {
+ dst-version = src-version;
+ rmb(); /* fetch version before data */
+ dst-tsc_timestamp = src-tsc_timestamp;
+ dst-system_timestamp = src-system_time;
+ dst-tsc_to_nsec_mul = src-tsc_to_system_mul;
+ dst-tsc_shift = src-tsc_shift;
+
[PATCH 2/5] Make xen use the paravirt clocksource structs and functions.
This patch updates the xen guest to use the pvclock structs
and helper functions.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/xen/Kconfig|1 +
arch/x86/xen/time.c | 130 ---
include/xen/interface/xen.h |5 +-
3 files changed, 14 insertions(+), 122 deletions(-)
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 2e641be..3a4f16a 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -5,6 +5,7 @@
config XEN
bool Xen guest support
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on X86_32
depends on X86_CMPXCHG X86_TSC !(X86_VISWS || X86_VOYAGER)
help
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index c39e1a5..bf31fb5 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -13,6 +13,7 @@
#include linux/clockchips.h
#include linux/kernel_stat.h
+#include asm/pvclock.h
#include asm/xen/hypervisor.h
#include asm/xen/hypercall.h
@@ -30,17 +31,6 @@
static cycle_t xen_clocksource_read(void);
-/* These are perodically updated in shared_info, and then copied here. */
-struct shadow_time_info {
- u64 tsc_timestamp; /* TSC at last update of time vals. */
- u64 system_timestamp; /* Time, in nanosecs, since boot.*/
- u32 tsc_to_nsec_mul;
- int tsc_shift;
- u32 version;
-};
-
-static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
-
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
@@ -230,121 +220,26 @@ unsigned long xen_cpu_khz(void)
return xen_khz;
}
-/*
- * Reads a consistent set of time-base values from Xen, into a shadow data
- * area.
- */
-static unsigned get_time_values_from_xen(void)
-{
- struct vcpu_time_info *src;
- struct shadow_time_info *dst;
-
- /* src is shared memory with the hypervisor, so we need to
- make sure we get a consistent snapshot, even in the face of
- being preempted. */
- src = __get_cpu_var(xen_vcpu)-time;
- dst = __get_cpu_var(shadow_time);
-
- do {
- dst-version = src-version;
- rmb(); /* fetch version before data */
- dst-tsc_timestamp = src-tsc_timestamp;
- dst-system_timestamp = src-system_time;
- dst-tsc_to_nsec_mul = src-tsc_to_system_mul;
- dst-tsc_shift = src-tsc_shift;
- rmb(); /* test version after fetching data */
- } while ((src-version 1) | (dst-version ^ src-version));
-
- return dst-version;
-}
-
-/*
- * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
- * yielding a 64-bit result.
- */
-static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
-{
- u64 product;
-#ifdef __i386__
- u32 tmp1, tmp2;
-#endif
-
- if (shift 0)
- delta = -shift;
- else
- delta = shift;
-
-#ifdef __i386__
- __asm__ (
- mul %5 ;
- mov %4,%%eax ;
- mov %%edx,%4 ;
- mul %5 ;
- xor %5,%5;
- add %4,%%eax ;
- adc %5,%%edx ;
- : =A (product), =r (tmp1), =r (tmp2)
- : a ((u32)delta), 1 ((u32)(delta 32)), 2 (mul_frac) );
-#elif __x86_64__
- __asm__ (
- mul %%rdx ; shrd $32,%%rdx,%%rax
- : =a (product) : 0 (delta), d ((u64)mul_frac) );
-#else
-#error implement me!
-#endif
-
- return product;
-}
-
-static u64 get_nsec_offset(struct shadow_time_info *shadow)
-{
- u64 now, delta;
- now = native_read_tsc();
- delta = now - shadow-tsc_timestamp;
- return scale_delta(delta, shadow-tsc_to_nsec_mul, shadow-tsc_shift);
-}
-
static cycle_t xen_clocksource_read(void)
{
- struct shadow_time_info *shadow = get_cpu_var(shadow_time);
+struct vcpu_time_info *src;
cycle_t ret;
- unsigned version;
-
- do {
- version = get_time_values_from_xen();
- barrier();
- ret = shadow-system_timestamp + get_nsec_offset(shadow);
- barrier();
- } while (version != __get_cpu_var(xen_vcpu)-time.version);
-
- put_cpu_var(shadow_time);
+ src = get_cpu_var(xen_vcpu)-time;
+ ret = pvclock_clocksource_read((void*)src);
+ put_cpu_var(xen_vcpu);
return ret;
}
static void xen_read_wallclock(struct timespec *ts)
{
- const struct shared_info *s = HYPERVISOR_shared_info;
- u32 version;
- u64 delta;
- struct timespec now;
-
- /* get wallclock at system boot */
- do {
- version = s-wc_version;
- rmb(); /* fetch version before time */
- now.tv_sec = s-wc_sec;
- now.tv_nsec = s-wc_nsec;
- rmb(); /* fetch time before
[PATCH 4/5] Make kvm guest use the paravirt clocksource structs and functions.
This patch updates the kvm host code to use the pvclock structs
and functions, thereby making it compatible with Xen.
The patch also fixes an initialization bug: on SMP systems the
per-cpu has two different locations early at boot and after CPU
bringup. kvmclock must take that in account when registering the
physical address within the host.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/Kconfig |1 +
arch/x86/kernel/kvmclock.c | 91 ---
2 files changed, 35 insertions(+), 57 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5fc46c1..b631288 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -383,6 +383,7 @@ config VMI
config KVM_CLOCK
bool KVM paravirtualized clock
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on !(X86_VISWS || X86_VOYAGER)
help
Turning on this option will allow you to run a paravirtualized clock
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 08a3098..927f0c5 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -18,6 +18,7 @@
#include linux/clocksource.h
#include linux/kvm_para.h
+#include asm/pvclock.h
#include asm/arch_hooks.h
#include asm/msr.h
#include asm/apic.h
@@ -36,18 +37,9 @@ static int parse_no_kvmclock(char *arg)
early_param(no-kvmclock, parse_no_kvmclock);
/* The hypervisor will put information about time periodically here */
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct kvm_vcpu_time_info, hv_clock);
-#define get_clock(cpu, field) per_cpu(hv_clock, cpu).field
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock);
+static struct pvclock_wall_clock wall_clock;
-static inline u64 kvm_get_delta(u64 last_tsc)
-{
- int cpu = smp_processor_id();
- u64 delta = native_read_tsc() - last_tsc;
- return (delta * get_clock(cpu, tsc_to_system_mul)) KVM_SCALE;
-}
-
-static struct kvm_wall_clock wall_clock;
-static cycle_t kvm_clock_read(void);
/*
* The wallclock is the time of day when we booted. Since then, some time may
* have elapsed since the hypervisor wrote the data. So we try to account for
@@ -55,64 +47,37 @@ static cycle_t kvm_clock_read(void);
*/
static unsigned long kvm_get_wallclock(void)
{
- u32 wc_sec, wc_nsec;
- u64 delta;
+ struct pvclock_vcpu_time_info *vcpu_time;
struct timespec ts;
- int version, nsec;
int low, high;
low = (int)__pa(wall_clock);
high = ((u64)__pa(wall_clock) 32);
-
- delta = kvm_clock_read();
-
native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
- do {
- version = wall_clock.wc_version;
- rmb();
- wc_sec = wall_clock.wc_sec;
- wc_nsec = wall_clock.wc_nsec;
- rmb();
- } while ((wall_clock.wc_version != version) || (version 1));
-
- delta = kvm_clock_read() - delta;
- delta += wc_nsec;
- nsec = do_div(delta, NSEC_PER_SEC);
- set_normalized_timespec(ts, wc_sec + delta, nsec);
- /*
-* Of all mechanisms of time adjustment I've tested, this one
-* was the champion!
-*/
- return ts.tv_sec + 1;
+
+ vcpu_time = get_cpu_var(hv_clock);
+ pvclock_read_wallclock(wall_clock, vcpu_time, ts);
+ put_cpu_var(hv_clock);
+
+ return ts.tv_sec;
}
static int kvm_set_wallclock(unsigned long now)
{
- return 0;
+ return -1;
}
-/*
- * This is our read_clock function. The host puts an tsc timestamp each time
- * it updates a new time. Without the tsc adjustment, we can have a situation
- * in which a vcpu starts to run earlier (smaller system_time), but probes
- * time later (compared to another vcpu), leading to backwards time
- */
static cycle_t kvm_clock_read(void)
{
- u64 last_tsc, now;
- int cpu;
-
- preempt_disable();
- cpu = smp_processor_id();
-
- last_tsc = get_clock(cpu, tsc_timestamp);
- now = get_clock(cpu, system_time);
+ struct pvclock_vcpu_time_info *src;
+ cycle_t ret;
- now += kvm_get_delta(last_tsc);
- preempt_enable();
-
- return now;
+ src = get_cpu_var(hv_clock);
+ ret = pvclock_clocksource_read(src);
+ put_cpu_var(hv_clock);
+ return ret;
}
+
static struct clocksource kvm_clock = {
.name = kvm-clock,
.read = kvm_clock_read,
@@ -123,13 +88,14 @@ static struct clocksource kvm_clock = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-static int kvm_register_clock(void)
+static int kvm_register_clock(char *txt)
{
int cpu = smp_processor_id();
int low, high;
low = (int)__pa(per_cpu(hv_clock, cpu)) | 1;
high = ((u64)__pa(per_cpu(hv_clock, cpu)) 32);
-
+ printk(KERN_INFO kvm-clock: cpu %d, msr %x:%x, %s\n,
+ cpu, high, low, txt);
return
[PATCH 5/5] Remove now unused structs from kvm_para.h
The kvm_* structs are obsoleted by the pvclock_* ones.
Now all users have been switched over and the old structs
can be dropped.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
include/asm-x86/kvm_para.h | 18 --
1 files changed, 0 insertions(+), 18 deletions(-)
diff --git a/include/asm-x86/kvm_para.h b/include/asm-x86/kvm_para.h
index 5098459..bfd9900 100644
--- a/include/asm-x86/kvm_para.h
+++ b/include/asm-x86/kvm_para.h
@@ -48,24 +48,6 @@ struct kvm_mmu_op_release_pt {
#ifdef __KERNEL__
#include asm/processor.h
-/* xen binary-compatible interface. See xen headers for details */
-struct kvm_vcpu_time_info {
- uint32_t version;
- uint32_t pad0;
- uint64_t tsc_timestamp;
- uint64_t system_time;
- uint32_t tsc_to_system_mul;
- int8_t tsc_shift;
- int8_t pad[3];
-} __attribute__((__packed__)); /* 32 bytes */
-
-struct kvm_wall_clock {
- uint32_t wc_version;
- uint32_t wc_sec;
- uint32_t wc_nsec;
-} __attribute__((__packed__));
-
-
extern void kvmclock_init(void);
--
1.5.4.1
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Re: [PATCH 5/5] Remove now unused structs from kvm_para.h
You sent these patches to kvm-owner, ie. the mailing list owner, and not the list itself which would be plain kvm. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
[PATCH 0/5] paravirt clock source patches, #4
paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. cheers, Gerd ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
[PATCH 3/5] Make kvm host use the paravirt clocksource structs.
This patch updates the kvm host code to use the pvclock structs.
It also makes the paravirt clock compatible with Xen.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/kvm/x86.c | 75 ---
include/asm-x86/kvm_host.h |4 ++-
2 files changed, 65 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 77fb2bd..7a62860 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -499,8 +499,8 @@ static int do_set_msr(struct kvm_vcpu *vcpu, unsigned
index, u64 *data)
static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
static int version;
- struct kvm_wall_clock wc;
- struct timespec wc_ts;
+ struct pvclock_wall_clock wc;
+ struct timespec now, sys, boot;
if (!wall_clock)
return;
@@ -509,10 +509,19 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t
wall_clock)
kvm_write_guest(kvm, wall_clock, version, sizeof(version));
- wc_ts = current_kernel_time();
- wc.wc_sec = wc_ts.tv_sec;
- wc.wc_nsec = wc_ts.tv_nsec;
- wc.wc_version = version;
+ /*
+* The guest calculates current wall clock time by adding
+* system time (updated by kvm_write_guest_time below) to the
+* wall clock specified here. guest system time equals host
+* system time for us, thus we must fill in host boot time here.
+*/
+ now = current_kernel_time();
+ ktime_get_ts(sys);
+ boot = ns_to_timespec(timespec_to_ns(now) - timespec_to_ns(sys));
+
+ wc.sec = boot.tv_sec;
+ wc.nsec = boot.tv_nsec;
+ wc.version = version;
kvm_write_guest(kvm, wall_clock, wc, sizeof(wc));
@@ -520,6 +529,45 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t
wall_clock)
kvm_write_guest(kvm, wall_clock, version, sizeof(version));
}
+static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
+{
+ uint32_t quotient, remainder;
+
+ /* Don't try to replace with do_div(), this one calculates
+* (dividend 32) / divisor */
+ __asm__ ( divl %4
+ : =a (quotient), =d (remainder)
+ : 0 (0), 1 (dividend), r (divisor) );
+ return quotient;
+}
+
+static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info
*hv_clock)
+{
+ uint64_t nsecs = 10LL;
+ int32_t shift = 0;
+ uint64_t tps64;
+ uint32_t tps32;
+
+ tps64 = tsc_khz * 1000LL;
+ while (tps64 nsecs*2) {
+ tps64 = 1;
+ shift--;
+ }
+
+ tps32 = (uint32_t)tps64;
+ while (tps32 = (uint32_t)nsecs) {
+ tps32 = 1;
+ shift++;
+ }
+
+ hv_clock-tsc_shift = shift;
+ hv_clock-tsc_to_system_mul = div_frac(nsecs, tps32);
+
+ pr_debug(%s: tsc_khz %u, tsc_shift %d, tsc_mul %u\n,
+__FUNCTION__, tsc_khz, hv_clock-tsc_shift,
+hv_clock-tsc_to_system_mul);
+}
+
static void kvm_write_guest_time(struct kvm_vcpu *v)
{
struct timespec ts;
@@ -530,6 +578,11 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
if ((!vcpu-time_page))
return;
+ if (unlikely(vcpu-hv_clock_tsc_khz != tsc_khz)) {
+ kvm_set_time_scale(tsc_khz, vcpu-hv_clock);
+ vcpu-hv_clock_tsc_khz = tsc_khz;
+ }
+
/* Keep irq disabled to prevent changes to the clock */
local_irq_save(flags);
kvm_get_msr(v, MSR_IA32_TIME_STAMP_COUNTER,
@@ -544,14 +597,14 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
/*
* The interface expects us to write an even number signaling that the
* update is finished. Since the guest won't see the intermediate
-* state, we just write 2 at the end
+* state, we just increase by 2 at the end.
*/
- vcpu-hv_clock.version = 2;
+ vcpu-hv_clock.version += 2;
shared_kaddr = kmap_atomic(vcpu-time_page, KM_USER0);
memcpy(shared_kaddr + vcpu-time_offset, vcpu-hv_clock,
- sizeof(vcpu-hv_clock));
+ sizeof(vcpu-hv_clock));
kunmap_atomic(shared_kaddr, KM_USER0);
@@ -639,10 +692,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64
data)
/* ...but clean it before doing the actual write */
vcpu-arch.time_offset = data ~(PAGE_MASK | 1);
- vcpu-arch.hv_clock.tsc_to_system_mul =
- clocksource_khz2mult(tsc_khz, 22);
- vcpu-arch.hv_clock.tsc_shift = 22;
-
down_read(current-mm-mmap_sem);
vcpu-arch.time_page =
gfn_to_page(vcpu-kvm, data PAGE_SHIFT);
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index cd50380..459461c 100644
--- a/include/asm-x86/kvm_host.h
+++
Re: [PATCH 0/5] paravirt clock source patches, #4
Gerd Hoffmann wrote: paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. This all looks pretty good. How do you want this to get into the kernel? J ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
Re: [PATCH 0/5] paravirt clock source patches, #4
Jeremy Fitzhardinge wrote: Gerd Hoffmann wrote: paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. This all looks pretty good. How do you want this to get into the kernel? J -- http://kraxel.fedorapeople.org/xenner/ ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
Re: [PATCH 1/5] Add structs and functions for paravirt clocksource.
Gerd Hoffmann wrote:
+/*
+ * These structs MUST NOT be changed.
+ * They are the ABI between hypervisor and guest OS.
+ * Both Xen and KVM are using this.
+ *
+ * pvclock_vcpu_time_info holds the system time and the tsc timestamp
+ * of the last update. So the guest can use the tsc delta to get a
+ * more precise system time.
You should note that these are per-cpu parameters.
+ *
+ * pvclock_wall_clock references the point in time when the system
+ * time was zero (usually boot time), thus the guest calculates the
+ * current wall clock by adding the system time.
+ *
+ * Protocol for the version fields is: hypervisor raises it (making
+ * it uneven) before it starts updating the fields and raises it again
+ * (making it even) when it is done. Thus the guest can make sure the
+ * time values it got are consistent by checking the version before
+ * and after reading them.
+ */
+
+struct pvclock_vcpu_time_info {
+ uint32_t version;
Use the standard u32/u64 I think (or the __u32 forms, maybe).
+ uint32_t pad0;
+ uint64_t tsc_timestamp;
+ uint64_t system_time;
+ uint32_t tsc_to_system_mul;
+ int8_t tsc_shift;
+ int8_t pad[3];
+} __attribute__((__packed__)); /* 32 bytes */
+
+struct pvclock_wall_clock {
+ uint32_t version;
+ uint32_t sec;
+ uint32_t nsec;
+} __attribute__((__packed__));
+
+#endif /* __ASSEMBLY__ */
+#endif /* _ASM_X86_PVCLOCK_ABI_H_ */
diff --git a/include/asm-x86/pvclock.h b/include/asm-x86/pvclock.h
new file mode 100644
index 000..85b1bba
--- /dev/null
+++ b/include/asm-x86/pvclock.h
@@ -0,0 +1,13 @@
+#ifndef _ASM_X86_PVCLOCK_H_
+#define _ASM_X86_PVCLOCK_H_
+
+#include linux/clocksource.h
+#include asm/pvclock-abi.h
+
+/* some helper functions for xen and kvm pv clock sources */
+cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
+void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
+ struct pvclock_vcpu_time_info *vcpu,
+ struct timespec *ts);
+
+#endif /* _ASM_X86_PVCLOCK_H_ */
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Re: [PATCH 2/5] Make xen use the paravirt clocksource structs and functions.
Gerd Hoffmann wrote:
This patch updates the xen guest to use the pvclock structs
and helper functions.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/xen/Kconfig|1 +
arch/x86/xen/time.c | 130
---
include/xen/interface/xen.h |5 +-
3 files changed, 14 insertions(+), 122 deletions(-)
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 2e641be..3a4f16a 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -5,6 +5,7 @@
config XEN
bool Xen guest support
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on X86_32
depends on X86_CMPXCHG X86_TSC !(X86_VISWS || X86_VOYAGER)
help
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index c39e1a5..bf31fb5 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -13,6 +13,7 @@
#include linux/clockchips.h
#include linux/kernel_stat.h
+#include asm/pvclock.h
#include asm/xen/hypervisor.h
#include asm/xen/hypercall.h
@@ -30,17 +31,6 @@
static cycle_t xen_clocksource_read(void);
-/* These are perodically updated in shared_info, and then copied here. */
-struct shadow_time_info {
- u64 tsc_timestamp; /* TSC at last update of time vals. */
- u64 system_timestamp; /* Time, in nanosecs, since boot.*/
- u32 tsc_to_nsec_mul;
- int tsc_shift;
- u32 version;
-};
-
-static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
-
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
@@ -230,121 +220,26 @@ unsigned long xen_cpu_khz(void)
return xen_khz;
}
-/*
- * Reads a consistent set of time-base values from Xen, into a shadow data
- * area.
- */
-static unsigned get_time_values_from_xen(void)
-{
- struct vcpu_time_info *src;
- struct shadow_time_info *dst;
-
- /* src is shared memory with the hypervisor, so we need to
-make sure we get a consistent snapshot, even in the face of
-being preempted. */
- src = __get_cpu_var(xen_vcpu)-time;
- dst = __get_cpu_var(shadow_time);
-
- do {
- dst-version = src-version;
- rmb(); /* fetch version before data */
- dst-tsc_timestamp = src-tsc_timestamp;
- dst-system_timestamp = src-system_time;
- dst-tsc_to_nsec_mul = src-tsc_to_system_mul;
- dst-tsc_shift = src-tsc_shift;
- rmb(); /* test version after fetching data */
- } while ((src-version 1) | (dst-version ^ src-version));
-
- return dst-version;
-}
-
-/*
- * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
- * yielding a 64-bit result.
- */
-static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
-{
- u64 product;
-#ifdef __i386__
- u32 tmp1, tmp2;
-#endif
-
- if (shift 0)
- delta = -shift;
- else
- delta = shift;
-
-#ifdef __i386__
- __asm__ (
- mul %5 ;
- mov %4,%%eax ;
- mov %%edx,%4 ;
- mul %5 ;
- xor %5,%5;
- add %4,%%eax ;
- adc %5,%%edx ;
- : =A (product), =r (tmp1), =r (tmp2)
- : a ((u32)delta), 1 ((u32)(delta 32)), 2 (mul_frac) );
-#elif __x86_64__
- __asm__ (
- mul %%rdx ; shrd $32,%%rdx,%%rax
- : =a (product) : 0 (delta), d ((u64)mul_frac) );
-#else
-#error implement me!
-#endif
-
- return product;
-}
-
-static u64 get_nsec_offset(struct shadow_time_info *shadow)
-{
- u64 now, delta;
- now = native_read_tsc();
- delta = now - shadow-tsc_timestamp;
- return scale_delta(delta, shadow-tsc_to_nsec_mul, shadow-tsc_shift);
-}
-
static cycle_t xen_clocksource_read(void)
{
- struct shadow_time_info *shadow = get_cpu_var(shadow_time);
+struct vcpu_time_info *src;
cycle_t ret;
- unsigned version;
-
- do {
- version = get_time_values_from_xen();
- barrier();
- ret = shadow-system_timestamp + get_nsec_offset(shadow);
- barrier();
- } while (version != __get_cpu_var(xen_vcpu)-time.version);
-
- put_cpu_var(shadow_time);
+ src = get_cpu_var(xen_vcpu)-time;
+ ret = pvclock_clocksource_read((void*)src);
+ put_cpu_var(xen_vcpu);
return ret;
}
static void xen_read_wallclock(struct timespec *ts)
{
- const struct shared_info *s = HYPERVISOR_shared_info;
- u32 version;
- u64 delta;
- struct timespec now;
-
- /* get wallclock at system boot */
- do {
- version = s-wc_version;
- rmb(); /* fetch version before time */
- now.tv_sec = s-wc_sec;
- now.tv_nsec = s-wc_nsec;
- rmb();
Re: [PATCH 0/5] paravirt clock source patches, #4
Jeremy Fitzhardinge wrote: Gerd Hoffmann wrote: paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. This all looks pretty good. How do you want this to get into the kernel? [ note: fixed up kvm list address: s/-owner// ] Good question. The kvm patches have dependencies on not-yet merged bits, so they have to go through the kvm queue. The first two can also go through Ingos x86 tree I guess. cheers, Gerd -- http://kraxel.fedorapeople.org/xenner/ ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
[PATCH 3/5] Make kvm host use the paravirt clocksource structs.
This patch updates the kvm host code to use the pvclock structs.
It also makes the paravirt clock compatible with Xen.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/kvm/x86.c | 75 ---
include/asm-x86/kvm_host.h |4 ++-
2 files changed, 65 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 77fb2bd..7a62860 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -499,8 +499,8 @@ static int do_set_msr(struct kvm_vcpu *vcpu, unsigned
index, u64 *data)
static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
static int version;
- struct kvm_wall_clock wc;
- struct timespec wc_ts;
+ struct pvclock_wall_clock wc;
+ struct timespec now, sys, boot;
if (!wall_clock)
return;
@@ -509,10 +509,19 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t
wall_clock)
kvm_write_guest(kvm, wall_clock, version, sizeof(version));
- wc_ts = current_kernel_time();
- wc.wc_sec = wc_ts.tv_sec;
- wc.wc_nsec = wc_ts.tv_nsec;
- wc.wc_version = version;
+ /*
+* The guest calculates current wall clock time by adding
+* system time (updated by kvm_write_guest_time below) to the
+* wall clock specified here. guest system time equals host
+* system time for us, thus we must fill in host boot time here.
+*/
+ now = current_kernel_time();
+ ktime_get_ts(sys);
+ boot = ns_to_timespec(timespec_to_ns(now) - timespec_to_ns(sys));
+
+ wc.sec = boot.tv_sec;
+ wc.nsec = boot.tv_nsec;
+ wc.version = version;
kvm_write_guest(kvm, wall_clock, wc, sizeof(wc));
@@ -520,6 +529,45 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t
wall_clock)
kvm_write_guest(kvm, wall_clock, version, sizeof(version));
}
+static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
+{
+ uint32_t quotient, remainder;
+
+ /* Don't try to replace with do_div(), this one calculates
+* (dividend 32) / divisor */
+ __asm__ ( divl %4
+ : =a (quotient), =d (remainder)
+ : 0 (0), 1 (dividend), r (divisor) );
+ return quotient;
+}
+
+static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info
*hv_clock)
+{
+ uint64_t nsecs = 10LL;
+ int32_t shift = 0;
+ uint64_t tps64;
+ uint32_t tps32;
+
+ tps64 = tsc_khz * 1000LL;
+ while (tps64 nsecs*2) {
+ tps64 = 1;
+ shift--;
+ }
+
+ tps32 = (uint32_t)tps64;
+ while (tps32 = (uint32_t)nsecs) {
+ tps32 = 1;
+ shift++;
+ }
+
+ hv_clock-tsc_shift = shift;
+ hv_clock-tsc_to_system_mul = div_frac(nsecs, tps32);
+
+ pr_debug(%s: tsc_khz %u, tsc_shift %d, tsc_mul %u\n,
+__FUNCTION__, tsc_khz, hv_clock-tsc_shift,
+hv_clock-tsc_to_system_mul);
+}
+
static void kvm_write_guest_time(struct kvm_vcpu *v)
{
struct timespec ts;
@@ -530,6 +578,11 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
if ((!vcpu-time_page))
return;
+ if (unlikely(vcpu-hv_clock_tsc_khz != tsc_khz)) {
+ kvm_set_time_scale(tsc_khz, vcpu-hv_clock);
+ vcpu-hv_clock_tsc_khz = tsc_khz;
+ }
+
/* Keep irq disabled to prevent changes to the clock */
local_irq_save(flags);
kvm_get_msr(v, MSR_IA32_TIME_STAMP_COUNTER,
@@ -544,14 +597,14 @@ static void kvm_write_guest_time(struct kvm_vcpu *v)
/*
* The interface expects us to write an even number signaling that the
* update is finished. Since the guest won't see the intermediate
-* state, we just write 2 at the end
+* state, we just increase by 2 at the end.
*/
- vcpu-hv_clock.version = 2;
+ vcpu-hv_clock.version += 2;
shared_kaddr = kmap_atomic(vcpu-time_page, KM_USER0);
memcpy(shared_kaddr + vcpu-time_offset, vcpu-hv_clock,
- sizeof(vcpu-hv_clock));
+ sizeof(vcpu-hv_clock));
kunmap_atomic(shared_kaddr, KM_USER0);
@@ -639,10 +692,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64
data)
/* ...but clean it before doing the actual write */
vcpu-arch.time_offset = data ~(PAGE_MASK | 1);
- vcpu-arch.hv_clock.tsc_to_system_mul =
- clocksource_khz2mult(tsc_khz, 22);
- vcpu-arch.hv_clock.tsc_shift = 22;
-
down_read(current-mm-mmap_sem);
vcpu-arch.time_page =
gfn_to_page(vcpu-kvm, data PAGE_SHIFT);
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index cd50380..459461c 100644
--- a/include/asm-x86/kvm_host.h
+++
[PATCH 5/5] Remove now unused structs from kvm_para.h
The kvm_* structs are obsoleted by the pvclock_* ones.
Now all users have been switched over and the old structs
can be dropped.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
include/asm-x86/kvm_para.h | 18 --
1 files changed, 0 insertions(+), 18 deletions(-)
diff --git a/include/asm-x86/kvm_para.h b/include/asm-x86/kvm_para.h
index 5098459..bfd9900 100644
--- a/include/asm-x86/kvm_para.h
+++ b/include/asm-x86/kvm_para.h
@@ -48,24 +48,6 @@ struct kvm_mmu_op_release_pt {
#ifdef __KERNEL__
#include asm/processor.h
-/* xen binary-compatible interface. See xen headers for details */
-struct kvm_vcpu_time_info {
- uint32_t version;
- uint32_t pad0;
- uint64_t tsc_timestamp;
- uint64_t system_time;
- uint32_t tsc_to_system_mul;
- int8_t tsc_shift;
- int8_t pad[3];
-} __attribute__((__packed__)); /* 32 bytes */
-
-struct kvm_wall_clock {
- uint32_t wc_version;
- uint32_t wc_sec;
- uint32_t wc_nsec;
-} __attribute__((__packed__));
-
-
extern void kvmclock_init(void);
--
1.5.4.1
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[PATCH 2/5] Make xen use the paravirt clocksource structs and functions.
This patch updates the xen guest to use the pvclock structs
and helper functions.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/xen/Kconfig|1 +
arch/x86/xen/time.c | 132 ---
include/xen/interface/xen.h |7 +-
3 files changed, 16 insertions(+), 124 deletions(-)
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 2e641be..3a4f16a 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -5,6 +5,7 @@
config XEN
bool Xen guest support
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on X86_32
depends on X86_CMPXCHG X86_TSC !(X86_VISWS || X86_VOYAGER)
help
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index c39e1a5..64f9e00 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -13,6 +13,7 @@
#include linux/clockchips.h
#include linux/kernel_stat.h
+#include asm/pvclock.h
#include asm/xen/hypervisor.h
#include asm/xen/hypercall.h
@@ -30,17 +31,6 @@
static cycle_t xen_clocksource_read(void);
-/* These are perodically updated in shared_info, and then copied here. */
-struct shadow_time_info {
- u64 tsc_timestamp; /* TSC at last update of time vals. */
- u64 system_timestamp; /* Time, in nanosecs, since boot.*/
- u32 tsc_to_nsec_mul;
- int tsc_shift;
- u32 version;
-};
-
-static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
-
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
@@ -218,7 +208,7 @@ unsigned long long xen_sched_clock(void)
unsigned long xen_cpu_khz(void)
{
u64 xen_khz = 100ULL 32;
- const struct vcpu_time_info *info =
+ const struct pvclock_vcpu_time_info *info =
HYPERVISOR_shared_info-vcpu_info[0].time;
do_div(xen_khz, info-tsc_to_system_mul);
@@ -230,121 +220,26 @@ unsigned long xen_cpu_khz(void)
return xen_khz;
}
-/*
- * Reads a consistent set of time-base values from Xen, into a shadow data
- * area.
- */
-static unsigned get_time_values_from_xen(void)
-{
- struct vcpu_time_info *src;
- struct shadow_time_info *dst;
-
- /* src is shared memory with the hypervisor, so we need to
- make sure we get a consistent snapshot, even in the face of
- being preempted. */
- src = __get_cpu_var(xen_vcpu)-time;
- dst = __get_cpu_var(shadow_time);
-
- do {
- dst-version = src-version;
- rmb(); /* fetch version before data */
- dst-tsc_timestamp = src-tsc_timestamp;
- dst-system_timestamp = src-system_time;
- dst-tsc_to_nsec_mul = src-tsc_to_system_mul;
- dst-tsc_shift = src-tsc_shift;
- rmb(); /* test version after fetching data */
- } while ((src-version 1) | (dst-version ^ src-version));
-
- return dst-version;
-}
-
-/*
- * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
- * yielding a 64-bit result.
- */
-static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
-{
- u64 product;
-#ifdef __i386__
- u32 tmp1, tmp2;
-#endif
-
- if (shift 0)
- delta = -shift;
- else
- delta = shift;
-
-#ifdef __i386__
- __asm__ (
- mul %5 ;
- mov %4,%%eax ;
- mov %%edx,%4 ;
- mul %5 ;
- xor %5,%5;
- add %4,%%eax ;
- adc %5,%%edx ;
- : =A (product), =r (tmp1), =r (tmp2)
- : a ((u32)delta), 1 ((u32)(delta 32)), 2 (mul_frac) );
-#elif __x86_64__
- __asm__ (
- mul %%rdx ; shrd $32,%%rdx,%%rax
- : =a (product) : 0 (delta), d ((u64)mul_frac) );
-#else
-#error implement me!
-#endif
-
- return product;
-}
-
-static u64 get_nsec_offset(struct shadow_time_info *shadow)
-{
- u64 now, delta;
- now = native_read_tsc();
- delta = now - shadow-tsc_timestamp;
- return scale_delta(delta, shadow-tsc_to_nsec_mul, shadow-tsc_shift);
-}
-
static cycle_t xen_clocksource_read(void)
{
- struct shadow_time_info *shadow = get_cpu_var(shadow_time);
+struct pvclock_vcpu_time_info *src;
cycle_t ret;
- unsigned version;
-
- do {
- version = get_time_values_from_xen();
- barrier();
- ret = shadow-system_timestamp + get_nsec_offset(shadow);
- barrier();
- } while (version != __get_cpu_var(xen_vcpu)-time.version);
-
- put_cpu_var(shadow_time);
+ src = get_cpu_var(xen_vcpu)-time;
+ ret = pvclock_clocksource_read(src);
+ put_cpu_var(xen_vcpu);
return ret;
}
static void xen_read_wallclock(struct timespec *ts)
{
- const struct shared_info *s = HYPERVISOR_shared_info;
- u32 version;
-
[PATCH 0/5] paravirt clock source patches, #5
paravirt clock source patches, next round. There is now a pvclock-abi.h file with the structs and some longish comments in it and everybody is switched over to use the stuff in there. Some minor tweaks after super-fast review by Jeremy. The queue is on top of the kvm git tree. The first two patches should have no kvm dependencies and should apply to linus tree just fine. cheers, Gerd ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
[PATCH 1/5] Add structs and functions for paravirt clocksource.
This patch adds structs for the paravirt clocksource ABI
used by both xen and kvm (pvclock-abi.h).
It also adds some helper functions to read system time and
wall clock time from a paravirtual clocksource (pvclock.[ch]).
They are based on the xen code. They are enabled using
CONFIG_PARAVIRT_CLOCK.
Subsequent patches of this series will put the code in use.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/Kconfig |4 +
arch/x86/kernel/Makefile |1 +
arch/x86/kernel/pvclock.c | 141 +
include/asm-x86/pvclock-abi.h | 42
include/asm-x86/pvclock.h | 13
5 files changed, 201 insertions(+), 0 deletions(-)
create mode 100644 arch/x86/kernel/pvclock.c
create mode 100644 include/asm-x86/pvclock-abi.h
create mode 100644 include/asm-x86/pvclock.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index dcbec34..5fc46c1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -410,6 +410,10 @@ config PARAVIRT
over full virtualization. However, when run without a hypervisor
the kernel is theoretically slower and slightly larger.
+config PARAVIRT_CLOCK
+ bool
+ default n
+
endif
config MEMTEST_BOOTPARAM
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 5e618c3..77807d4 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_VMI) += vmi_32.o vmiclock_32.o
obj-$(CONFIG_KVM_GUEST)+= kvm.o
obj-$(CONFIG_KVM_CLOCK)+= kvmclock.o
obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt_patch_$(BITS).o
+obj-$(CONFIG_PARAVIRT_CLOCK) += pvclock.o
obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
new file mode 100644
index 000..05fbe9a
--- /dev/null
+++ b/arch/x86/kernel/pvclock.c
@@ -0,0 +1,141 @@
+/* paravirtual clock -- common code used by kvm/xen
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#include linux/kernel.h
+#include linux/percpu.h
+#include asm/pvclock.h
+
+/*
+ * These are perodically updated
+ *xen: magic shared_info page
+ *kvm: gpa registered via msr
+ * and then copied here.
+ */
+struct pvclock_shadow_time {
+ u64 tsc_timestamp; /* TSC at last update of time vals. */
+ u64 system_timestamp; /* Time, in nanosecs, since boot.*/
+ u32 tsc_to_nsec_mul;
+ int tsc_shift;
+ u32 version;
+};
+
+/*
+ * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
+ * yielding a 64-bit result.
+ */
+static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
+{
+ u64 product;
+#ifdef __i386__
+ u32 tmp1, tmp2;
+#endif
+
+ if (shift 0)
+ delta = -shift;
+ else
+ delta = shift;
+
+#ifdef __i386__
+ __asm__ (
+ mul %5 ;
+ mov %4,%%eax ;
+ mov %%edx,%4 ;
+ mul %5 ;
+ xor %5,%5;
+ add %4,%%eax ;
+ adc %5,%%edx ;
+ : =A (product), =r (tmp1), =r (tmp2)
+ : a ((u32)delta), 1 ((u32)(delta 32)), 2 (mul_frac) );
+#elif __x86_64__
+ __asm__ (
+ mul %%rdx ; shrd $32,%%rdx,%%rax
+ : =a (product) : 0 (delta), d ((u64)mul_frac) );
+#else
+#error implement me!
+#endif
+
+ return product;
+}
+
+static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
+{
+ u64 delta = native_read_tsc() - shadow-tsc_timestamp;
+ return scale_delta(delta, shadow-tsc_to_nsec_mul, shadow-tsc_shift);
+}
+
+/*
+ * Reads a consistent set of time-base values from hypervisor,
+ * into a shadow data area.
+ */
+static unsigned pvclock_get_time_values(struct pvclock_shadow_time *dst,
+ struct pvclock_vcpu_time_info *src)
+{
+ do {
+ dst-version = src-version;
+ rmb(); /* fetch version before data */
+ dst-tsc_timestamp = src-tsc_timestamp;
+ dst-system_timestamp = src-system_time;
+ dst-tsc_to_nsec_mul = src-tsc_to_system_mul;
+ dst-tsc_shift = src-tsc_shift;
+
[PATCH 4/5] Make kvm guest use the paravirt clocksource structs and functions.
This patch updates the kvm host code to use the pvclock structs
and functions, thereby making it compatible with Xen.
The patch also fixes an initialization bug: on SMP systems the
per-cpu has two different locations early at boot and after CPU
bringup. kvmclock must take that in account when registering the
physical address within the host.
Signed-off-by: Gerd Hoffmann [EMAIL PROTECTED]
---
arch/x86/Kconfig |1 +
arch/x86/kernel/kvmclock.c | 91 ---
2 files changed, 35 insertions(+), 57 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5fc46c1..b631288 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -383,6 +383,7 @@ config VMI
config KVM_CLOCK
bool KVM paravirtualized clock
select PARAVIRT
+ select PARAVIRT_CLOCK
depends on !(X86_VISWS || X86_VOYAGER)
help
Turning on this option will allow you to run a paravirtualized clock
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 08a3098..927f0c5 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -18,6 +18,7 @@
#include linux/clocksource.h
#include linux/kvm_para.h
+#include asm/pvclock.h
#include asm/arch_hooks.h
#include asm/msr.h
#include asm/apic.h
@@ -36,18 +37,9 @@ static int parse_no_kvmclock(char *arg)
early_param(no-kvmclock, parse_no_kvmclock);
/* The hypervisor will put information about time periodically here */
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct kvm_vcpu_time_info, hv_clock);
-#define get_clock(cpu, field) per_cpu(hv_clock, cpu).field
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock);
+static struct pvclock_wall_clock wall_clock;
-static inline u64 kvm_get_delta(u64 last_tsc)
-{
- int cpu = smp_processor_id();
- u64 delta = native_read_tsc() - last_tsc;
- return (delta * get_clock(cpu, tsc_to_system_mul)) KVM_SCALE;
-}
-
-static struct kvm_wall_clock wall_clock;
-static cycle_t kvm_clock_read(void);
/*
* The wallclock is the time of day when we booted. Since then, some time may
* have elapsed since the hypervisor wrote the data. So we try to account for
@@ -55,64 +47,37 @@ static cycle_t kvm_clock_read(void);
*/
static unsigned long kvm_get_wallclock(void)
{
- u32 wc_sec, wc_nsec;
- u64 delta;
+ struct pvclock_vcpu_time_info *vcpu_time;
struct timespec ts;
- int version, nsec;
int low, high;
low = (int)__pa(wall_clock);
high = ((u64)__pa(wall_clock) 32);
-
- delta = kvm_clock_read();
-
native_write_msr(MSR_KVM_WALL_CLOCK, low, high);
- do {
- version = wall_clock.wc_version;
- rmb();
- wc_sec = wall_clock.wc_sec;
- wc_nsec = wall_clock.wc_nsec;
- rmb();
- } while ((wall_clock.wc_version != version) || (version 1));
-
- delta = kvm_clock_read() - delta;
- delta += wc_nsec;
- nsec = do_div(delta, NSEC_PER_SEC);
- set_normalized_timespec(ts, wc_sec + delta, nsec);
- /*
-* Of all mechanisms of time adjustment I've tested, this one
-* was the champion!
-*/
- return ts.tv_sec + 1;
+
+ vcpu_time = get_cpu_var(hv_clock);
+ pvclock_read_wallclock(wall_clock, vcpu_time, ts);
+ put_cpu_var(hv_clock);
+
+ return ts.tv_sec;
}
static int kvm_set_wallclock(unsigned long now)
{
- return 0;
+ return -1;
}
-/*
- * This is our read_clock function. The host puts an tsc timestamp each time
- * it updates a new time. Without the tsc adjustment, we can have a situation
- * in which a vcpu starts to run earlier (smaller system_time), but probes
- * time later (compared to another vcpu), leading to backwards time
- */
static cycle_t kvm_clock_read(void)
{
- u64 last_tsc, now;
- int cpu;
-
- preempt_disable();
- cpu = smp_processor_id();
-
- last_tsc = get_clock(cpu, tsc_timestamp);
- now = get_clock(cpu, system_time);
+ struct pvclock_vcpu_time_info *src;
+ cycle_t ret;
- now += kvm_get_delta(last_tsc);
- preempt_enable();
-
- return now;
+ src = get_cpu_var(hv_clock);
+ ret = pvclock_clocksource_read(src);
+ put_cpu_var(hv_clock);
+ return ret;
}
+
static struct clocksource kvm_clock = {
.name = kvm-clock,
.read = kvm_clock_read,
@@ -123,13 +88,14 @@ static struct clocksource kvm_clock = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-static int kvm_register_clock(void)
+static int kvm_register_clock(char *txt)
{
int cpu = smp_processor_id();
int low, high;
low = (int)__pa(per_cpu(hv_clock, cpu)) | 1;
high = ((u64)__pa(per_cpu(hv_clock, cpu)) 32);
-
+ printk(KERN_INFO kvm-clock: cpu %d, msr %x:%x, %s\n,
+ cpu, high, low, txt);
return
Re: [RFC 2/3] virtio_console: use virtqueue notification for hvc_console
On Tuesday 03 June 2008, Christian Borntraeger wrote: +/* The hvc device */ +struct hvc_struct *hvc; + I guess this should be static, a three letter identifier for a global variable is not really unique. Arnd ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
Re: [RFC 1/3] hvc_console: rework setup to replace irq functions with callbacks (not word wrapped)
On Tuesday 03 June 2008, Christian Borntraeger wrote:
@@ -42,22 +42,48 @@
*/
#define HVC_ALLOC_TTY_ADAPTERS 8
+struct hvc_struct {
+ spinlock_t lock;
+ int index;
+ struct tty_struct *tty;
+ unsigned int count;
+ int do_wakeup;
+ char *outbuf;
+ int outbuf_size;
+ int n_outbuf;
+ uint32_t vtermno;
+ struct hv_ops *ops;
+ int data;
+ struct list_head next;
+ struct kref kref; /* ref count hvc_struct lifetime */
+};
I don't see a reason to make this data structure known to other files,
so why not leave it in hvc_console.c?
+
+#ifdef CONFIG_HVC_IRQ
+/* default notifier for irq based notification */
+extern int notifier_add_irq(struct hvc_struct *hp, int irq);
+extern void notifier_del_irq(struct hvc_struct *hp, int irq);
+#endif
#endif // HVC_CONSOLE_H
Please remove the #ifdef around the declarations.
h Arnd
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Re: [RFC 1/3] hvc_console: rework setup to replace irq functions with callbacks
On Tuesday 03 June 2008 22:45:22 Christian Borntraeger wrote: This patch tries to change hvc_console to not use request_irq/free_irq if the backend does not use irqs. This allows virtio_console to use hvc_console without having a linker reference to request_irq/free_irq. Two questions. Is it possible to make the timer backoff a third kind of notifier? And is it possible to make the dependency static, rather than dynamic, or does someone need two options at runtime? Thanks, Rusty. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization
