Now that we have a flag that will tell the guest it was suspended, create an
interface for that communication using a KVM ioctl.
Signed-off-by: Eric B Munson <emunson@xxxxxxxxx>
Cc: mingo@xxxxxxxxxx
Cc: hpa@xxxxxxxxx
Cc: ryanh@xxxxxxxxxxxxxxxxxx
Cc: aliguori@xxxxxxxxxx
Cc: mtosatti@xxxxxxxxxx
Cc: jeremy.fitzhardinge@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Changes from V7:
Define KVM_CAP_GUEST_PAUSED and support check
Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add new ioctl description to api.txt
Documentation/virtual/kvm/api.txt | 13 +++++++++++++
arch/x86/kvm/x86.c | 21 +++++++++++++++++++++
include/linux/kvm.h | 3 +++
3 files changed, 37 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index e1d94bf..1931e5c 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1491,6 +1491,19 @@ following algorithm:
Some guests configure the LINT1 NMI input to cause a panic, aiding in
debugging.
+4.65 KVMCLOCK_GUEST_PAUSED
+
+Capability: KVM_CAP_GUEST_PAUSED
+Architechtures: Any that implement pvclocks (currently x86 only)
+Type: vcpu ioctl
+Parameters: None
+Returns: 0 on success, -1 on error
+
+This signals to the host kernel that the specified guest is being paused by
+userspace. The host will set a flag in the pvclock structure that is checked
+from the soft lockup watchdog. This ioctl can be called during pause or
+unpause.
+
5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1171def..b0b51cb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2056,6 +2056,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_X86_ROBUST_SINGLESTEP:
case KVM_CAP_XSAVE:
case KVM_CAP_ASYNC_PF:
+ case KVM_CAP_GUEST_PAUSED:
case KVM_CAP_GET_TSC_KHZ:
r = 1;
break;
@@ -2503,6 +2504,22 @@ static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu,
return r;
}
+/*
+ * kvm_set_guest_paused() indicates to the guest kernel that it has been
+ * stopped by the hypervisor. This function will be called from the host only.
+ * EINVAL is returned when the host attempts to set the flag for a guest that
+ * does not support pv clocks.
+ */
+static int kvm_set_guest_paused(struct kvm_vcpu *vcpu)
+{
+ struct pvclock_vcpu_time_info *src = &vcpu->arch.hv_clock;
+ if (!vcpu->arch.time_page)
+ return -EINVAL;
+ src->flags |= PVCLOCK_GUEST_STOPPED;
+ mark_page_dirty(vcpu->kvm, vcpu->arch.time >> PAGE_SHIFT);
+ return 0;
+}
+
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -2784,6 +2801,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
goto out;
}
+ case KVMCLOCK_GUEST_PAUSED: {
+ r = kvm_set_guest_paused(vcpu);
+ break;
+ }
default:
r = -EINVAL;
}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 68e67e5..4ffe0df 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -558,6 +558,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_PPC_PAPR 68
#define KVM_CAP_S390_GMAP 71
#define KVM_CAP_TSC_DEADLINE_TIMER 72
+#define KVM_CAP_GUEST_PAUSED 73
#ifdef KVM_CAP_IRQ_ROUTING
@@ -763,6 +764,8 @@ struct kvm_clock_data {
#define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce)
/* Available with KVM_CAP_RMA */
#define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma)
+/* VM is being stopped by host */
+#define KVMCLOCK_GUEST_PAUSED _IO(KVMIO, 0xaa)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
--
1.7.5.4
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