From: Zengruan Ye <yezengruan@huawei.com>
To: <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>,
<linux-doc@vger.kernel.org>,
<virtualization@lists.linux-foundation.org>
Cc: <yezengruan@huawei.com>, <maz@kernel.org>, <james.morse@arm.com>,
<linux@armlinux.org.uk>, <suzuki.poulose@arm.com>,
<julien.thierry.kdev@gmail.com>, <catalin.marinas@arm.com>,
<mark.rutland@arm.com>, <will@kernel.org>, <steven.price@arm.com>,
<daniel.lezcano@linaro.org>
Subject: [PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check
Date: Thu, 26 Dec 2019 21:58:32 +0800 [thread overview]
Message-ID: <20191226135833.1052-6-yezengruan@huawei.com> (raw)
In-Reply-To: <20191226135833.1052-1-yezengruan@huawei.com>
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 <yezengruan@huawei.com>
---
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 <asm/qrwlock.h>
#include <asm/qspinlock.h>
+#include <asm/paravirt.h>
/* 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 000000000000..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 <yezengruan@huawei.com>
+ */
+
+#include <linux/spinlock.h>
+#include <asm/paravirt.h>
+
+__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
next prev parent reply other threads:[~2019-12-26 13:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-26 13:58 [PATCH v2 0/6] KVM: arm64: VCPU preempted check support Zengruan Ye
2019-12-26 13:58 ` [PATCH v2 1/6] KVM: arm64: Document PV-lock interface Zengruan Ye
2020-01-09 14:53 ` Steven Price
2020-01-11 6:51 ` yezengruan
2019-12-26 13:58 ` [PATCH v2 2/6] KVM: arm64: Add SMCCC paravirtualised lock calls Zengruan Ye
2019-12-26 13:58 ` [PATCH v2 3/6] KVM: arm64: Support pvlock preempted via shared structure Zengruan Ye
2020-01-09 15:02 ` Steven Price
2020-01-11 7:30 ` yezengruan
2020-01-13 10:31 ` Steven Price
2019-12-26 13:58 ` [PATCH v2 4/6] KVM: arm64: Provide VCPU attributes for PV lock Zengruan Ye
2019-12-26 13:58 ` Zengruan Ye [this message]
2019-12-26 18:51 ` [PATCH v2 5/6] KVM: arm64: Add interface to support VCPU preempted check kbuild test robot
2019-12-27 6:52 ` yezengruan
2019-12-26 13:58 ` [PATCH v2 6/6] KVM: arm64: Support the VCPU preemption check Zengruan Ye
2020-01-09 15:09 ` Steven Price
2020-01-11 7:33 ` yezengruan
2020-01-13 12:12 ` [PATCH v2 0/6] KVM: arm64: VCPU preempted check support Will Deacon
2020-01-15 14:14 ` Marc Zyngier
2020-12-29 8:50 ` yezengruan
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