kvm: x86: implement KVM PM-notifier

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>
Message-Id: <20210606021045.14159-2-senozhatsky@chromium.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index f6b93a3..7a78b88 100644 (file)
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -46,6 +46,7 @@ config KVM
        select KVM_GENERIC_DIRTYLOG_READ_PROTECT
        select KVM_VFIO
        select SRCU
+       select HAVE_KVM_PM_NOTIFIER if PM
        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 d1fdbaa..3c5a33a 100644 (file)
--- 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>
 
@@ -5701,6 +5702,41 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
        return 0;
 }
 
+#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
+static int kvm_arch_suspend_notifier(struct kvm *kvm)
+{
+       struct kvm_vcpu *vcpu;
+       int i, ret = 0;
+
+       mutex_lock(&kvm->lock);
+       kvm_for_each_vcpu(i, vcpu, kvm) {
+               if (!vcpu->arch.pv_time_enabled)
+                       continue;
+
+               ret = kvm_set_guest_paused(vcpu);
+               if (ret) {
+                       kvm_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_HAVE_KVM_PM_NOTIFIER */
+
 long kvm_arch_vm_ioctl(struct file *filp,
                       unsigned int ioctl, unsigned long arg)
 {