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0021-KVM-arm64-Add-interface-to-support-PV-qspinlock.patch
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0021-KVM-arm64-Add-interface-to-support-PV-qspinlock.patch
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From e0e185e36ea8a9641dd4e5e410b49c423b0b93a0 Mon Sep 17 00:00:00 2001
From: AltArch Kernel <noreply@centos.org>
Date: Wed, 23 Sep 2020 16:56:12 +0800
Subject: [PATCH 21/25] KVM: arm64: Add interface to support PV qspinlock
euleros inclusion
category: feature
bugzilla: NA
DTS: #231
CVE: NA
--------------------------------
As kernel has used this interface, so lets support it.
---
arch/arm64/Kconfig | 14 ++++++++++++++
arch/arm64/include/asm/paravirt.h | 29 +++++++++++++++++++++++++++++
arch/arm64/include/asm/qspinlock.h | 14 +++++++++++---
arch/arm64/include/asm/qspinlock_paravirt.h | 12 ++++++++++++
arch/arm64/include/asm/spinlock.h | 3 +++
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/alternative.c | 1 +
arch/arm64/kernel/paravirt-spinlocks.c | 5 +++++
arch/arm64/kernel/paravirt.c | 4 ++++
9 files changed, 80 insertions(+), 3 deletions(-)
create mode 100644 arch/arm64/include/asm/qspinlock_paravirt.h
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e2b6212..5810e1c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -698,6 +698,7 @@ config NODES_SHIFT
config NUMA_AWARE_SPINLOCKS
bool "Numa-aware spinlocks"
depends on NUMA && QUEUED_SPINLOCKS
+ depends on PARAVIRT_SPINLOCKS
default n
help
Introduce NUMA (Non Uniform Memory Access) awareness into
@@ -782,6 +783,19 @@ config PARAVIRT
under a hypervisor, potentially improving performance significantly
over full virtualization.
+config PARAVIRT_SPINLOCKS
+ bool "Paravirtualization layer for spinlocks"
+ depends on PARAVIRT && SMP
+ help
+ Paravirtualized spinlocks allow a pvops backend to replace the
+ spinlock implementation with something virtualization-friendly
+ (for example, block the virtual CPU rather than spinning).
+
+ It has a minimal impact on native kernels and gives a nice performance
+ benefit on paravirtualized KVM kernels.
+
+ If you are unsure how to answer this question, answer Y.
+
config PARAVIRT_TIME_ACCOUNTING
bool "Paravirtual steal time accounting"
select PARAVIRT
diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h
index 62e9ba7..256e3f9 100644
--- a/arch/arm64/include/asm/paravirt.h
+++ b/arch/arm64/include/asm/paravirt.h
@@ -12,6 +12,12 @@ struct pv_time_ops {
};
struct pv_sched_ops {
+ void (*queued_spin_lock_slowpath)(struct qspinlock *lock, u32 val);
+ void (*queued_spin_unlock)(struct qspinlock *lock);
+
+ void (*wait)(u8 *ptr, u8 val);
+ void (*kick)(int cpu);
+
bool (*vcpu_is_preempted)(int cpu);
};
@@ -35,6 +41,29 @@ static inline bool pv_vcpu_is_preempted(int cpu)
return pv_ops.sched.vcpu_is_preempted(cpu);
}
+#if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS)
+bool pv_is_native_spin_unlock(void);
+static inline void pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
+{
+ return pv_ops.sched.queued_spin_lock_slowpath(lock, val);
+}
+
+static inline void pv_queued_spin_unlock(struct qspinlock *lock)
+{
+ return pv_ops.sched.queued_spin_unlock(lock);
+}
+
+static inline void pv_wait(u8 *ptr, u8 val)
+{
+ return pv_ops.sched.wait(ptr, val);
+}
+
+static inline void pv_kick(int cpu)
+{
+ return pv_ops.sched.kick(cpu);
+}
+#endif /* SMP && PARAVIRT_SPINLOCKS */
+
#else
#define pv_sched_init() do {} while (0)
diff --git a/arch/arm64/include/asm/qspinlock.h b/arch/arm64/include/asm/qspinlock.h
index 1d35bc7..23aff07 100644
--- a/arch/arm64/include/asm/qspinlock.h
+++ b/arch/arm64/include/asm/qspinlock.h
@@ -2,11 +2,19 @@
#ifndef _ASM_ARM64_QSPINLOCK_H
#define _ASM_ARM64_QSPINLOCK_H
-#ifdef CONFIG_NUMA_AWARE_SPINLOCKS
#include <asm-generic/qspinlock_types.h>
+#include <asm/paravirt.h>
+
+#define _Q_PENDING_LOOPS (1 << 9)
+#ifdef CONFIG_NUMA_AWARE_SPINLOCKS
extern void __cna_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+#endif
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_init_lock_hash(void);
+extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
#define queued_spin_unlock queued_spin_unlock
/**
@@ -22,12 +30,12 @@ static inline void native_queued_spin_unlock(struct qspinlock *lock)
static inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
{
- __cna_queued_spin_lock_slowpath(lock, val);
+ pv_queued_spin_lock_slowpath(lock, val);
}
static inline void queued_spin_unlock(struct qspinlock *lock)
{
- native_queued_spin_unlock(lock);
+ pv_queued_spin_unlock(lock);
}
#endif
diff --git a/arch/arm64/include/asm/qspinlock_paravirt.h b/arch/arm64/include/asm/qspinlock_paravirt.h
new file mode 100644
index 0000000..eba4be2
--- /dev/null
+++ b/arch/arm64/include/asm/qspinlock_paravirt.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ * Author: Zengruan Ye <yezengruan@huawei.com>
+ */
+
+#ifndef __ASM_QSPINLOCK_PARAVIRT_H
+#define __ASM_QSPINLOCK_PARAVIRT_H
+
+extern void __pv_queued_spin_unlock(struct qspinlock *lock);
+
+#endif
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h
index 6e8db57..4fb3eda 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -27,6 +27,9 @@
#define arch_read_relax(lock) cpu_relax()
#define arch_write_relax(lock) cpu_relax()
+/* How long a lock should spin before we consider blocking */
+#define SPIN_THRESHOLD (1 << 15)
+
/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index e1a562a..661b070 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -47,6 +47,7 @@ arm64-obj-$(CONFIG_ACPI) += acpi.o
arm64-obj-$(CONFIG_ACPI_NUMA) += acpi_numa.o
arm64-obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL) += acpi_parking_protocol.o
arm64-obj-$(CONFIG_PARAVIRT) += paravirt.o paravirt-spinlocks.o
+arm64-obj-$(CONFIG_PARAVIRT_SPINLOCKS) += paravirt.o paravirt-spinlocks.o
arm64-obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
arm64-obj-$(CONFIG_HIBERNATION) += hibernate.o hibernate-asm.o
arm64-obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o \
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index 5c4bce4..d2a019b 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -26,6 +26,7 @@
#include <asm/cpufeature.h>
#include <asm/insn.h>
#include <asm/sections.h>
+#include <asm/paravirt.h>
#include <linux/stop_machine.h>
#define __ALT_PTR(a,f) ((void *)&(a)->f + (a)->f)
diff --git a/arch/arm64/kernel/paravirt-spinlocks.c b/arch/arm64/kernel/paravirt-spinlocks.c
index fd733eb..3cb43f9 100644
--- a/arch/arm64/kernel/paravirt-spinlocks.c
+++ b/arch/arm64/kernel/paravirt-spinlocks.c
@@ -11,3 +11,8 @@ __visible bool __native_vcpu_is_preempted(int cpu)
{
return false;
}
+
+bool pv_is_native_spin_unlock(void)
+{
+ return false;
+}
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index 2370908..3edbcf8 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -30,6 +30,10 @@
struct static_key paravirt_steal_rq_enabled;
struct paravirt_patch_template pv_ops = {
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+ .sched.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
+ .sched.queued_spin_unlock = native_queued_spin_unlock,
+#endif
.sched.vcpu_is_preempted = __native_vcpu_is_preempted,
};
EXPORT_SYMBOL_GPL(pv_ops);
--
1.8.3.1