From ce9add0587211ddca1969e24d91f2fd23fdb2473 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Tue, 1 Jun 2021 22:18:32 +0800
Subject: [PATCH] cpuidle-haltpoll: disable host side polling when kvm
virtualized
mainline inclusion
from mainline-5.4
commit a1c4423b02b2121108e3ea9580741e0f26309a48
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=34
CVE: NA
When performing guest side polling, it is not necessary to
also perform host side polling.
So disable host side polling, via the new MSR interface,
when loading cpuidle-haltpoll driver.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Yubo Miao <miaoyubo@huawei.com>
Signed-off-by: Xiangyou Xie <xiexiangyou@huawei.com>
Reviewed-by: Hailiang Zhang <zhang.zhanghailiang@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jiajun Chen <chenjiajun8@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
arch/x86/Kconfig | 10 ++++++
arch/x86/include/asm/cpuidle_haltpoll.h | 8 +++++
arch/x86/kernel/kvm.c | 42 +++++++++++++++++++++++++
drivers/cpuidle/cpuidle-haltpoll.c | 9 +++++-
include/linux/cpuidle_haltpoll.h | 16 ++++++++++
5 files changed, 84 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/include/asm/cpuidle_haltpoll.h
create mode 100644 include/linux/cpuidle_haltpoll.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2e9c5bb959e9..e8d2ca2009d8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -786,6 +786,7 @@ config KVM_GUEST
bool "KVM Guest support (including kvmclock)"
depends on PARAVIRT
select PARAVIRT_CLOCK
+ select ARCH_CPUIDLE_HALTPOLL
default y
---help---
This option enables various optimizations for running under the KVM
@@ -794,6 +795,15 @@ config KVM_GUEST
underlying device model, the host provides the guest with
timing infrastructure such as time of day, and system time
+config ARCH_CPUIDLE_HALTPOLL
+ def_bool n
+ prompt "Disable host haltpoll when loading haltpoll driver"
+ help
+ If virtualized under KVM, disable host haltpoll. When loading
+ haltpoll driver, It allows the guest vcpus to poll for a
+ specified amount of time before halting, The execution of
+ haltpoll on the host is redundant.
+
config KVM_DEBUG_FS
bool "Enable debug information for KVM Guests in debugfs"
depends on KVM_GUEST && DEBUG_FS
diff --git a/arch/x86/include/asm/cpuidle_haltpoll.h b/arch/x86/include/asm/cpuidle_haltpoll.h
new file mode 100644
index 000000000000..ff8607d81526
--- /dev/null
+++ b/arch/x86/include/asm/cpuidle_haltpoll.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ARCH_HALTPOLL_H
+#define _ARCH_HALTPOLL_H
+
+void arch_haltpoll_enable(void);
+void arch_haltpoll_disable(void);
+
+#endif
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index cee45d46e67d..40f40bd08ab7 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -866,3 +866,45 @@ void __init kvm_spinlock_init(void)
}
#endif /* CONFIG_PARAVIRT_SPINLOCKS */
+
+#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
+
+static void kvm_disable_host_haltpoll(void *i)
+{
+ wrmsrl(MSR_KVM_POLL_CONTROL, 0);
+}
+
+static void kvm_enable_host_haltpoll(void *i)
+{
+ wrmsrl(MSR_KVM_POLL_CONTROL, 1);
+}
+
+void arch_haltpoll_enable(void)
+{
+ if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
+ pr_err_once("kvm: host does not support poll control\n");
+ pr_err_once("kvm: host upgrade recommended\n");
+ return;
+ }
+
+ preempt_disable();
+ /* Enable guest halt poll disables host halt poll */
+ kvm_disable_host_haltpoll(NULL);
+ smp_call_function(kvm_disable_host_haltpoll, NULL, 1);
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
+
+void arch_haltpoll_disable(void)
+{
+ if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
+ return;
+
+ preempt_disable();
+ /* Enable guest halt poll disables host halt poll */
+ kvm_enable_host_haltpoll(NULL);
+ smp_call_function(kvm_enable_host_haltpoll, NULL, 1);
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
+#endif
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 35cfb53e9287..9ac093dcbb01 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/sched/idle.h>
#include <linux/kvm_para.h>
+#include <linux/cpuidle_haltpoll.h>
static int default_enter_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
@@ -47,6 +48,7 @@ static struct cpuidle_driver haltpoll_driver = {
static int __init haltpoll_init(void)
{
+ int ret;
struct cpuidle_driver *drv = &haltpoll_driver;
cpuidle_poll_state_init(drv);
@@ -54,11 +56,16 @@ static int __init haltpoll_init(void)
if (!kvm_para_available())
return 0;
- return cpuidle_register(&haltpoll_driver, NULL);
+ ret = cpuidle_register(&haltpoll_driver, NULL);
+ if (ret == 0)
+ arch_haltpoll_enable();
+
+ return ret;
}
static void __exit haltpoll_exit(void)
{
+ arch_haltpoll_disable();
cpuidle_unregister(&haltpoll_driver);
}
diff --git a/include/linux/cpuidle_haltpoll.h b/include/linux/cpuidle_haltpoll.h
new file mode 100644
index 000000000000..fe5954c2409e
--- /dev/null
+++ b/include/linux/cpuidle_haltpoll.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CPUIDLE_HALTPOLL_H
+#define _CPUIDLE_HALTPOLL_H
+
+#ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
+#include <asm/cpuidle_haltpoll.h>
+#else
+static inline void arch_haltpoll_enable(void)
+{
+}
+
+static inline void arch_haltpoll_disable(void)
+{
+}
+#endif
+#endif
--
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