[PATCHv2 2/2] kvm: x86: implement KVM PM-notifier

Sergey Senozhatsky
2021-06-05T02:32:09Z

Implement PM hibernation/suspend prepare notifiers so that KVM
can reliably set PVCLOCK_GUEST_STOPPED on VCPUs and properly
suspend VMs.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
arch/x86/kvm/Kconfig | 1 +
arch/x86/kvm/x86.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index fb8efb387aff..f8e6689f490b 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -43,6 +43,7 @@ config KVM
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_VFIO
select SRCU
+ select HAVE_KVM_PM_NOTIFIER
help
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b594275d49b5..533d3d010a21 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -58,6 +58,7 @@
#include <linux/sched/isolation.h>
#include <linux/mem_encrypt.h>
#include <linux/entry-kvm.h>
+#include <linux/suspend.h>

#include <trace/events/kvm.h>

@@ -5615,6 +5616,38 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
return 0;
}

+#if defined(CONFIG_PM) && defined(CONFIG_HAVE_KVM_PM_NOTIFIER)
+static int kvm_arch_suspend_notifier(struct kvm *kvm)
+{
+ struct kvm_vcpu *vcpu;
+ int i, ret;
+
+ mutex_lock(&kvm->lock);
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ ret = kvm_set_guest_paused(vcpu);
+ if (ret) {
+ pr_err("Failed to pause guest VCPU%d: %d\n",
+ vcpu->vcpu_id, ret);
+ break;
+ }
+ }
+ mutex_unlock(&kvm->lock);
+
+ return ret ? NOTIFY_BAD : NOTIFY_DONE;
+}
+
+int kvm_arch_pm_notifier(struct kvm *kvm, unsigned long state)
+{
+ switch (state) {
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ return kvm_arch_suspend_notifier(kvm);
+ }
+
+ return NOTIFY_DONE;
+}
+#endif /* CONFIG_PM && CONFIG_HAVE_KVM_PM_NOTIFIER */
+
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
--
2.32.0.rc1.229.g3e70b5a671-goog