Re: [PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check
Hi,
On 2019/12/27 2:51, kbuild test robot wrote:
> Hi Zengruan,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on kvmarm/next]
> [also build test ERROR on kvm/linux-next linus/master v5.5-rc3 next-20191220]
> [cannot apply to arm64/for-next/core]
> [if your patch is applied to the wrong git tree, please drop us a note to help
> improve the system. BTW, we also suggest to use '--base' option to specify the
> base tree in git format-patch, please see
> https://stackoverflow.com/a/37406982]
>
> url:
> https://github.com/0day-ci/linux/commits/Zengruan-Ye/KVM-arm64-VCPU-preempted-check-support/20191227-000637
> base: https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
> config: arm64-alldefconfig (attached as .config)
> compiler: aarch64-linux-gcc (GCC) 7.5.0
> reproduce:
> wget
> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
> ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> GCC_VERSION=7.5.0 make.cross ARCH=arm64
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot
>
> All errors (new ones prefixed by >>):
>
>In file included from include/linux/spinlock.h:89:0,
> from include/linux/radix-tree.h:16,
> from include/linux/idr.h:15,
> from include/linux/kernfs.h:13,
> from include/linux/sysfs.h:16,
> from include/linux/kobject.h:20,
> from include/linux/of.h:17,
> from include/linux/irqdomain.h:35,
> from include/linux/acpi.h:13,
> from include/acpi/apei.h:9,
> from include/acpi/ghes.h:5,
> from include/linux/arm_sdei.h:8,
> from arch/arm64/kernel/asm-offsets.c:10:
>arch/arm64/include/asm/spinlock.h: In function 'vcpu_is_preempted':
>>> arch/arm64/include/asm/spinlock.h:18:9: error: implicit declaration of
>>> function 'pv_vcpu_is_preempted'; did you mean 'vcpu_is_preempted'?
>>> [-Werror=implicit-function-declaration]
> return pv_vcpu_is_preempted(cpu);
> ^~~~
> vcpu_is_preempted
>cc1: some warnings being treated as errors
>make[2]: *** [arch/arm64/kernel/asm-offsets.s] Error 1
>make[2]: Target '__build' not remade because of errors.
>make[1]: *** [prepare0] Error 2
>make[1]: Target 'prepare' not remade because of errors.
>make: *** [sub-make] Error 2
>27 real 5 user 7 sys 48.63% cpu make prepare
>
> vim +18 arch/arm64/include/asm/spinlock.h
>
> 14
> 15#define vcpu_is_preempted vcpu_is_preempted
> 16static inline bool vcpu_is_preempted(long cpu)
> 17{
> > 18return pv_vcpu_is_preempted(cpu);
> 19}
> 20
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org Intel Corporation
>
Thanks for posting this, I'll update the code to fix this issue.
Thanks,
Zengruan
---
arch/arm64/include/asm/spinlock.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/include/asm/spinlock.h
b/arch/arm64/include/asm/spinlock.h
index 45ff1b2949a6..b5d1982414c5 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -12,10 +12,12 @@
/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
+#ifdef CONFIG_PARAVIRT
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(long cpu)
{
return pv_vcpu_is_preempted(cpu);
}
+#endif // CONFIG_PARAVIRT
#endif /* __ASM_SPINLOCK_H */
--
2.19.1
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Re: [PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check
Hi Zengruan,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on kvmarm/next]
[also build test ERROR on kvm/linux-next linus/master v5.5-rc3 next-20191220]
[cannot apply to arm64/for-next/core]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url:
https://github.com/0day-ci/linux/commits/Zengruan-Ye/KVM-arm64-VCPU-preempted-check-support/20191227-000637
base: https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
config: arm64-alldefconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 7.5.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.5.0 make.cross ARCH=arm64
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot
All errors (new ones prefixed by >>):
In file included from include/linux/spinlock.h:89:0,
from include/linux/radix-tree.h:16,
from include/linux/idr.h:15,
from include/linux/kernfs.h:13,
from include/linux/sysfs.h:16,
from include/linux/kobject.h:20,
from include/linux/of.h:17,
from include/linux/irqdomain.h:35,
from include/linux/acpi.h:13,
from include/acpi/apei.h:9,
from include/acpi/ghes.h:5,
from include/linux/arm_sdei.h:8,
from arch/arm64/kernel/asm-offsets.c:10:
arch/arm64/include/asm/spinlock.h: In function 'vcpu_is_preempted':
>> arch/arm64/include/asm/spinlock.h:18:9: error: implicit declaration of
>> function 'pv_vcpu_is_preempted'; did you mean 'vcpu_is_preempted'?
>> [-Werror=implicit-function-declaration]
return pv_vcpu_is_preempted(cpu);
^~~~
vcpu_is_preempted
cc1: some warnings being treated as errors
make[2]: *** [arch/arm64/kernel/asm-offsets.s] Error 1
make[2]: Target '__build' not remade because of errors.
make[1]: *** [prepare0] Error 2
make[1]: Target 'prepare' not remade because of errors.
make: *** [sub-make] Error 2
27 real 5 user 7 sys 48.63% cpu make prepare
vim +18 arch/arm64/include/asm/spinlock.h
14
15 #define vcpu_is_preempted vcpu_is_preempted
16 static inline bool vcpu_is_preempted(long cpu)
17 {
> 18 return pv_vcpu_is_preempted(cpu);
19 }
20
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org Intel Corporation
.config.gz
Description: application/gzip
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[PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the CPU as parameter and return true if the CPU is preempted.
Then kernel can break the spin loops upon the retval of vcpu_is_preempted.
As kernel has used this interface, So lets support it.
Signed-off-by: Zengruan Ye
---
arch/arm64/include/asm/paravirt.h | 12
arch/arm64/include/asm/spinlock.h | 7 +++
arch/arm64/kernel/Makefile | 2 +-
arch/arm64/kernel/paravirt-spinlocks.c | 13 +
arch/arm64/kernel/paravirt.c | 4 +++-
5 files changed, 36 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/kernel/paravirt-spinlocks.c
diff --git a/arch/arm64/include/asm/paravirt.h
b/arch/arm64/include/asm/paravirt.h
index cf3a0fd7c1a7..7b1c81b544bb 100644
--- a/arch/arm64/include/asm/paravirt.h
+++ b/arch/arm64/include/asm/paravirt.h
@@ -11,8 +11,13 @@ struct pv_time_ops {
unsigned long long (*steal_clock)(int cpu);
};
+struct pv_lock_ops {
+ bool (*vcpu_is_preempted)(int cpu);
+};
+
struct paravirt_patch_template {
struct pv_time_ops time;
+ struct pv_lock_ops lock;
};
extern struct paravirt_patch_template pv_ops;
@@ -24,6 +29,13 @@ static inline u64 paravirt_steal_clock(int cpu)
int __init pv_time_init(void);
+__visible bool __native_vcpu_is_preempted(int cpu);
+
+static inline bool pv_vcpu_is_preempted(int cpu)
+{
+ return pv_ops.lock.vcpu_is_preempted(cpu);
+}
+
#else
#define pv_time_init() do {} while (0)
diff --git a/arch/arm64/include/asm/spinlock.h
b/arch/arm64/include/asm/spinlock.h
index b093b287babf..45ff1b2949a6 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -7,8 +7,15 @@
#include
#include
+#include
/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(long cpu)
+{
+ return pv_vcpu_is_preempted(cpu);
+}
+
#endif /* __ASM_SPINLOCK_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index fc6488660f64..b23cdae433a4 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -50,7 +50,7 @@ obj-$(CONFIG_ARMV8_DEPRECATED)+=
armv8_deprecated.o
obj-$(CONFIG_ACPI) += acpi.o
obj-$(CONFIG_ACPI_NUMA)+= acpi_numa.o
obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
-obj-$(CONFIG_PARAVIRT) += paravirt.o
+obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt-spinlocks.o
obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o
\
diff --git a/arch/arm64/kernel/paravirt-spinlocks.c
b/arch/arm64/kernel/paravirt-spinlocks.c
new file mode 100644
index ..718aa773d45c
--- /dev/null
+++ b/arch/arm64/kernel/paravirt-spinlocks.c
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye
+ */
+
+#include
+#include
+
+__visible bool __native_vcpu_is_preempted(int cpu)
+{
+ return false;
+}
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index 1ef702b0be2d..d8f1ba8c22ce 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -26,7 +26,9 @@
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
-struct paravirt_patch_template pv_ops;
+struct paravirt_patch_template pv_ops = {
+ .lock.vcpu_is_preempted = __native_vcpu_is_preempted,
+};
EXPORT_SYMBOL_GPL(pv_ops);
struct pv_time_stolen_time_region {
--
2.19.1
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