* [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host
@ 2012-02-07 21:28 Eric B Munson
2012-02-07 21:28 ` Eric B Munson
` (5 more replies)
0 siblings, 6 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
Changes from V11:
Re-add asm-generic stub
Correct api.txt typo
add kvm_make_request() call after setting PVCLOCK_GUEST_STOPPED
Changes from V10:
Return ioctl to per vcpu instead of per vm
Changes from V9:
Use kvm_for_each_vcpu to iterate online vcpu's
Changes from V8:
Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu
Changes from V7:
Define KVM_CAP_GUEST_PAUSED and support check
Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED
Changes from V6:
Use __this_cpu_and when clearing the PVCLOCK_GUEST_STOPPED flag
Changes from V5:
Collapse generic check_and_clear_guest_stopped into patch 2
Include check_and_clear_guest_stopped defintion to ia64, s390, and powerpc
Change check_and_clear_guest_stopped to use __get_cpu_var instead of taking the
cpuid arg.
Protect check_and_clear_guest_stopped declaration with CONFIG_KVM_CLOCK check
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add description of KVMCLOCK_GUEST_PAUSED ioctl to api.txt
Changes from V3:
Include CC's on patch 3
Drop clear flag ioctl and have the watchdog clear the flag when it is reset
Changes from V2:
A new kvm functions defined in kvm_para.h, the only change to pvclock is the
initial flag definition
Changes from V1:
(Thanks Marcelo)
Host code has all been moved to arch/x86/kvm/x86.c
KVM_PAUSE_GUEST was renamed to KVM_GUEST_PAUSED
When a guest kernel is stopped by the host hypervisor it can look like a soft
lockup to the guest kernel. This false warning can mask later soft lockup
warnings which may be real. This patch series adds a method for a host
hypervisor to communicate to a guest kernel that it is being stopped. The
final patch in the series has the watchdog check this flag when it goes to
issue a soft lockup warning and skip the warning if the guest knows it was
stopped.
It was attempted to solve this in Qemu, but the side effects of saving and
restoring the clock and tsc for each vcpu put the wall clock of the guest behind
by the amount of time of the pause. This forces a guest to have ntp running
in order to keep the wall clock accurate.
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Eric B Munson (4):
Add flag to indicate that a vm was stopped by the host
Add functions to check if the host has stopped the vm
Add ioctl for KVMCLOCK_GUEST_STOPPED
Add check for suspended vm in softlockup detector
arch/ia64/include/asm/kvm_para.h | 5 +++++
arch/powerpc/include/asm/kvm_para.h | 5 +++++
arch/s390/include/asm/kvm_para.h | 5 +++++
arch/x86/include/asm/kvm_para.h | 8 ++++++++
arch/x86/include/asm/pvclock-abi.h | 1 +
arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++
include/asm-generic/kvm_para.h | 14 ++++++++++++++
include/linux/kvm.h | 3 +++
kernel/watchdog.c | 12 ++++++++++++
9 files changed, 74 insertions(+), 0 deletions(-)
create mode 100644 include/asm-generic/kvm_para.h
--
1.7.5.4
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 1/4 V12] Add flag to indicate that a vm was stopped by the host Eric B Munson
` (4 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
Changes from V11:
Re-add asm-generic stub
Correct api.txt typo
add kvm_make_request() call after setting PVCLOCK_GUEST_STOPPED
Changes from V10:
Return ioctl to per vcpu instead of per vm
Changes from V9:
Use kvm_for_each_vcpu to iterate online vcpu's
Changes from V8:
Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu
Changes from V7:
Define KVM_CAP_GUEST_PAUSED and support check
Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED
Changes from V6:
Use __this_cpu_and when clearing the PVCLOCK_GUEST_STOPPED flag
Changes from V5:
Collapse generic check_and_clear_guest_stopped into patch 2
Include check_and_clear_guest_stopped defintion to ia64, s390, and powerpc
Change check_and_clear_guest_stopped to use __get_cpu_var instead of taking the
cpuid arg.
Protect check_and_clear_guest_stopped declaration with CONFIG_KVM_CLOCK check
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add description of KVMCLOCK_GUEST_PAUSED ioctl to api.txt
Changes from V3:
Include CC's on patch 3
Drop clear flag ioctl and have the watchdog clear the flag when it is reset
Changes from V2:
A new kvm functions defined in kvm_para.h, the only change to pvclock is the
initial flag definition
Changes from V1:
(Thanks Marcelo)
Host code has all been moved to arch/x86/kvm/x86.c
KVM_PAUSE_GUEST was renamed to KVM_GUEST_PAUSED
When a guest kernel is stopped by the host hypervisor it can look like a soft
lockup to the guest kernel. This false warning can mask later soft lockup
warnings which may be real. This patch series adds a method for a host
hypervisor to communicate to a guest kernel that it is being stopped. The
final patch in the series has the watchdog check this flag when it goes to
issue a soft lockup warning and skip the warning if the guest knows it was
stopped.
It was attempted to solve this in Qemu, but the side effects of saving and
restoring the clock and tsc for each vcpu put the wall clock of the guest behind
by the amount of time of the pause. This forces a guest to have ntp running
in order to keep the wall clock accurate.
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Eric B Munson (4):
Add flag to indicate that a vm was stopped by the host
Add functions to check if the host has stopped the vm
Add ioctl for KVMCLOCK_GUEST_STOPPED
Add check for suspended vm in softlockup detector
arch/ia64/include/asm/kvm_para.h | 5 +++++
arch/powerpc/include/asm/kvm_para.h | 5 +++++
arch/s390/include/asm/kvm_para.h | 5 +++++
arch/x86/include/asm/kvm_para.h | 8 ++++++++
arch/x86/include/asm/pvclock-abi.h | 1 +
arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++
include/asm-generic/kvm_para.h | 14 ++++++++++++++
include/linux/kvm.h | 3 +++
kernel/watchdog.c | 12 ++++++++++++
9 files changed, 74 insertions(+), 0 deletions(-)
create mode 100644 include/asm-generic/kvm_para.h
--
1.7.5.4
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/4 V12] Add flag to indicate that a vm was stopped by the host
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
2012-02-07 21:28 ` Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 2/4 V12] Add functions to check if the host has stopped the vm Eric B Munson
` (3 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
This flag will be used to check if the vm was stopped by the host when a soft
lockup was detected. The host will set the flag when it stops the guest. On
resume, the guest will check this flag if a soft lockup is detected and skip
issuing the warning.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
arch/x86/include/asm/pvclock-abi.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/pvclock-abi.h b/arch/x86/include/asm/pvclock-abi.h
index 35f2d19..6167fd7 100644
--- a/arch/x86/include/asm/pvclock-abi.h
+++ b/arch/x86/include/asm/pvclock-abi.h
@@ -40,5 +40,6 @@ struct pvclock_wall_clock {
} __attribute__((__packed__));
#define PVCLOCK_TSC_STABLE_BIT (1 << 0)
+#define PVCLOCK_GUEST_STOPPED (1 << 1)
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_PVCLOCK_ABI_H */
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/4 V12] Add functions to check if the host has stopped the vm
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 1/4 V12] Add flag to indicate that a vm was stopped by the host Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED Eric B Munson
` (2 subsequent siblings)
5 siblings, 1 reply; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
When a host stops or suspends a VM it will set a flag to show this. The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
asm-generic changes Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from V11:
Re-add the missing asm-generic stub for check_and_clear_guest_stopped()
Changes from V6:
Use __this_cpu_and when clearing the PVCLOCK_GUEST_STOPPED flag
Changes from V5:
Collapse generic stubs into this patch
check_and_clear_guest_stopped() takes no args and uses __get_cpu_var()
Include individual definitions in ia64, s390, and powerpc
arch/ia64/include/asm/kvm_para.h | 5 +++++
arch/powerpc/include/asm/kvm_para.h | 5 +++++
arch/s390/include/asm/kvm_para.h | 5 +++++
arch/x86/include/asm/kvm_para.h | 8 ++++++++
arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++
include/asm-generic/kvm_para.h | 14 ++++++++++++++
6 files changed, 58 insertions(+), 0 deletions(-)
create mode 100644 include/asm-generic/kvm_para.h
diff --git a/arch/ia64/include/asm/kvm_para.h b/arch/ia64/include/asm/kvm_para.h
index 1588aee..2019cb9 100644
--- a/arch/ia64/include/asm/kvm_para.h
+++ b/arch/ia64/include/asm/kvm_para.h
@@ -26,6 +26,11 @@ static inline unsigned int kvm_arch_para_features(void)
return 0;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif
#endif
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index 50533f9..1f80293 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -169,6 +169,11 @@ static inline unsigned int kvm_arch_para_features(void)
return r;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif /* __KERNEL__ */
#endif /* __POWERPC_KVM_PARA_H__ */
diff --git a/arch/s390/include/asm/kvm_para.h b/arch/s390/include/asm/kvm_para.h
index 6964db2..a988329 100644
--- a/arch/s390/include/asm/kvm_para.h
+++ b/arch/s390/include/asm/kvm_para.h
@@ -149,6 +149,11 @@ static inline unsigned int kvm_arch_para_features(void)
return 0;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif
#endif /* __S390_KVM_PARA_H */
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 734c376..99c4bbe 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -95,6 +95,14 @@ struct kvm_vcpu_pv_apf_data {
extern void kvmclock_init(void);
extern int kvm_register_clock(char *txt);
+#ifdef CONFIG_KVM_CLOCK
+bool kvm_check_and_clear_guest_paused(void);
+#else
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+#endif /* CONFIG_KVMCLOCK */
/* This instruction is vmcall. On non-VT architectures, it will generate a
* trap that we will then rewrite to the appropriate instruction.
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 44842d7..bdf6423 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -22,6 +22,7 @@
#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
+#include <linux/hardirq.h>
#include <asm/x86_init.h>
#include <asm/reboot.h>
@@ -114,6 +115,26 @@ static void kvm_get_preset_lpj(void)
preset_lpj = lpj;
}
+bool kvm_check_and_clear_guest_paused(void)
+{
+ bool ret = false;
+ struct pvclock_vcpu_time_info *src;
+
+ /*
+ * per_cpu() is safe here because this function is only called from
+ * timer functions where preemption is already disabled.
+ */
+ WARN_ON(!in_atomic());
+ src = &__get_cpu_var(hv_clock);
+ if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
+ __this_cpu_and(hv_clock.flags, ~PVCLOCK_GUEST_STOPPED);
+ ret = true;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_check_and_clear_guest_paused);
+
static struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
diff --git a/include/asm-generic/kvm_para.h b/include/asm-generic/kvm_para.h
new file mode 100644
index 0000000..05ef7e7
--- /dev/null
+++ b/include/asm-generic/kvm_para.h
@@ -0,0 +1,14 @@
+#ifndef _ASM_GENERIC_KVM_PARA_H
+#define _ASM_GENERIC_KVM_PARA_H
+
+
+/*
+ * This function is used by architectures that support kvm to avoid issuing
+ * false soft lockup messages.
+ */
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
+#endif
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/4 V12] Add functions to check if the host has stopped the vm
2012-02-07 21:28 ` [PATCH 2/4 V12] Add functions to check if the host has stopped the vm Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
0 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
When a host stops or suspends a VM it will set a flag to show this. The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
asm-generic changes Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from V11:
Re-add the missing asm-generic stub for check_and_clear_guest_stopped()
Changes from V6:
Use __this_cpu_and when clearing the PVCLOCK_GUEST_STOPPED flag
Changes from V5:
Collapse generic stubs into this patch
check_and_clear_guest_stopped() takes no args and uses __get_cpu_var()
Include individual definitions in ia64, s390, and powerpc
arch/ia64/include/asm/kvm_para.h | 5 +++++
arch/powerpc/include/asm/kvm_para.h | 5 +++++
arch/s390/include/asm/kvm_para.h | 5 +++++
arch/x86/include/asm/kvm_para.h | 8 ++++++++
arch/x86/kernel/kvmclock.c | 21 +++++++++++++++++++++
include/asm-generic/kvm_para.h | 14 ++++++++++++++
6 files changed, 58 insertions(+), 0 deletions(-)
create mode 100644 include/asm-generic/kvm_para.h
diff --git a/arch/ia64/include/asm/kvm_para.h b/arch/ia64/include/asm/kvm_para.h
index 1588aee..2019cb9 100644
--- a/arch/ia64/include/asm/kvm_para.h
+++ b/arch/ia64/include/asm/kvm_para.h
@@ -26,6 +26,11 @@ static inline unsigned int kvm_arch_para_features(void)
return 0;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif
#endif
diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h
index 50533f9..1f80293 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -169,6 +169,11 @@ static inline unsigned int kvm_arch_para_features(void)
return r;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif /* __KERNEL__ */
#endif /* __POWERPC_KVM_PARA_H__ */
diff --git a/arch/s390/include/asm/kvm_para.h b/arch/s390/include/asm/kvm_para.h
index 6964db2..a988329 100644
--- a/arch/s390/include/asm/kvm_para.h
+++ b/arch/s390/include/asm/kvm_para.h
@@ -149,6 +149,11 @@ static inline unsigned int kvm_arch_para_features(void)
return 0;
}
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
#endif
#endif /* __S390_KVM_PARA_H */
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index 734c376..99c4bbe 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -95,6 +95,14 @@ struct kvm_vcpu_pv_apf_data {
extern void kvmclock_init(void);
extern int kvm_register_clock(char *txt);
+#ifdef CONFIG_KVM_CLOCK
+bool kvm_check_and_clear_guest_paused(void);
+#else
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+#endif /* CONFIG_KVMCLOCK */
/* This instruction is vmcall. On non-VT architectures, it will generate a
* trap that we will then rewrite to the appropriate instruction.
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 44842d7..bdf6423 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -22,6 +22,7 @@
#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
+#include <linux/hardirq.h>
#include <asm/x86_init.h>
#include <asm/reboot.h>
@@ -114,6 +115,26 @@ static void kvm_get_preset_lpj(void)
preset_lpj = lpj;
}
+bool kvm_check_and_clear_guest_paused(void)
+{
+ bool ret = false;
+ struct pvclock_vcpu_time_info *src;
+
+ /*
+ * per_cpu() is safe here because this function is only called from
+ * timer functions where preemption is already disabled.
+ */
+ WARN_ON(!in_atomic());
+ src = &__get_cpu_var(hv_clock);
+ if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
+ __this_cpu_and(hv_clock.flags, ~PVCLOCK_GUEST_STOPPED);
+ ret = true;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kvm_check_and_clear_guest_paused);
+
static struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
diff --git a/include/asm-generic/kvm_para.h b/include/asm-generic/kvm_para.h
new file mode 100644
index 0000000..05ef7e7
--- /dev/null
+++ b/include/asm-generic/kvm_para.h
@@ -0,0 +1,14 @@
+#ifndef _ASM_GENERIC_KVM_PARA_H
+#define _ASM_GENERIC_KVM_PARA_H
+
+
+/*
+ * This function is used by architectures that support kvm to avoid issuing
+ * false soft lockup messages.
+ */
+static inline bool kvm_check_and_clear_guest_paused(void)
+{
+ return false;
+}
+
+#endif
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
` (2 preceding siblings ...)
2012-02-07 21:28 ` [PATCH 2/4 V12] Add functions to check if the host has stopped the vm Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 4/4] Add check for suspended vm in softlockup detector Eric B Munson
2012-02-07 23:04 ` [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
5 siblings, 1 reply; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
Now that we have a flag that will tell the guest it was suspended, create an
interface for that communication using a KVM ioctl.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from V11:
Correct typo in api.txt
Add kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu) call to kvm_set_guest_paused()
Changes from V10:
Return the ioctl to per vcpu instead of per vm
Changes from V9:
Use kvm_for_each_vcpu to iterate online vcpu's
Changes from V8:
Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu
Changes from V7:
Define KVM_CAP_GUEST_PAUSED and support check
Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add new ioctl description to api.txt
include/linux/kvm.h | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c3892fc..dbfc4f8 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -557,6 +557,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_MAX_VCPUS 66 /* returns max vcpus per vm */
#define KVM_CAP_PPC_PAPR 68
#define KVM_CAP_S390_GMAP 71
+#define KVM_CAP_GUEST_PAUSED 72
#ifdef KVM_CAP_IRQ_ROUTING
@@ -762,6 +763,8 @@ struct kvm_clock_data {
#define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce)
/* Available with KVM_CAP_RMA */
#define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
+/* VM is being stopped by host */
+#define KVMCLOCK_GUEST_PAUSED _IO(KVMIO, 0xaa)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED
2012-02-07 21:28 ` [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
0 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
Now that we have a flag that will tell the guest it was suspended, create an
interface for that communication using a KVM ioctl.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from V11:
Correct typo in api.txt
Add kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu) call to kvm_set_guest_paused()
Changes from V10:
Return the ioctl to per vcpu instead of per vm
Changes from V9:
Use kvm_for_each_vcpu to iterate online vcpu's
Changes from V8:
Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu
Changes from V7:
Define KVM_CAP_GUEST_PAUSED and support check
Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add new ioctl description to api.txt
include/linux/kvm.h | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c3892fc..dbfc4f8 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -557,6 +557,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_MAX_VCPUS 66 /* returns max vcpus per vm */
#define KVM_CAP_PPC_PAPR 68
#define KVM_CAP_S390_GMAP 71
+#define KVM_CAP_GUEST_PAUSED 72
#ifdef KVM_CAP_IRQ_ROUTING
@@ -762,6 +763,8 @@ struct kvm_clock_data {
#define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce)
/* Available with KVM_CAP_RMA */
#define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
+/* VM is being stopped by host */
+#define KVMCLOCK_GUEST_PAUSED _IO(KVMIO, 0xaa)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 4/4] Add check for suspended vm in softlockup detector
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
` (3 preceding siblings ...)
2012-02-07 21:28 ` [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED Eric B Munson
@ 2012-02-07 21:28 ` Eric B Munson
2012-02-07 23:04 ` [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
5 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 21:28 UTC (permalink / raw)
To: avi
Cc: Eric B Munson, mingo, hpa, ryanh, aliguori, mtosatti, kvm,
linux-arch, x86, linux-kernel
A suspended VM can cause spurious soft lockup warnings. To avoid these, the
watchdog now checks if the kernel knows it was stopped by the host and skips
the warning if so. When the watchdog is reset successfully, clear the guest
paused flag.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: ryanh@linux.vnet.ibm.com
Cc: aliguori@us.ibm.com
Cc: mtosatti@redhat.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from V3:
Clear the PAUSED flag when the watchdog is reset
kernel/watchdog.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 1d7bca7..91485e5 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -25,6 +25,7 @@
#include <linux/sysctl.h>
#include <asm/irq_regs.h>
+#include <linux/kvm_para.h>
#include <linux/perf_event.h>
int watchdog_enabled = 1;
@@ -280,6 +281,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
__this_cpu_write(softlockup_touch_sync, false);
sched_clock_tick();
}
+
+ /* Clear the guest paused flag on watchdog reset */
+ kvm_check_and_clear_guest_paused();
__touch_watchdog();
return HRTIMER_RESTART;
}
@@ -292,6 +296,14 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
*/
duration = is_softlockup(touch_ts);
if (unlikely(duration)) {
+ /*
+ * If a virtual machine is stopped by the host it can look to
+ * the watchdog like a soft lockup, check to see if the host
+ * stopped the vm before we issue the warning
+ */
+ if (kvm_check_and_clear_guest_paused())
+ return HRTIMER_RESTART;
+
/* only warn once */
if (__this_cpu_read(soft_watchdog_warn) == true)
return HRTIMER_RESTART;
--
1.7.5.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host
2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
` (4 preceding siblings ...)
2012-02-07 21:28 ` [PATCH 4/4] Add check for suspended vm in softlockup detector Eric B Munson
@ 2012-02-07 23:04 ` Eric B Munson
5 siblings, 0 replies; 9+ messages in thread
From: Eric B Munson @ 2012-02-07 23:04 UTC (permalink / raw)
To: avi
Cc: mingo, hpa, ryanh, aliguori, mtosatti, kvm, linux-arch, x86,
linux-kernel
I managed to miss the discussion from the V11 thread, I will work those
comments in tomorrow and send V13 as soon as that is done.
Eric
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2012-02-07 23:04 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2012-02-07 21:28 [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 1/4 V12] Add flag to indicate that a vm was stopped by the host Eric B Munson
2012-02-07 21:28 ` [PATCH 2/4 V12] Add functions to check if the host has stopped the vm Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 3/4 V12] Add ioctl for KVMCLOCK_GUEST_STOPPED Eric B Munson
2012-02-07 21:28 ` Eric B Munson
2012-02-07 21:28 ` [PATCH 4/4] Add check for suspended vm in softlockup detector Eric B Munson
2012-02-07 23:04 ` [PATCH 0/4 V12] Avoid soft lockup message when KVM is stopped by host Eric B Munson
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