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: arnd@xxxxxxxx
Cc: ryanh@xxxxxxxxxxxxxxxxxx
Cc: aliguori@xxxxxxxxxx
Cc: mtosatti@xxxxxxxxxx
Cc: jeremy.fitzhardinge@xxxxxxxxxx
Cc: levinsasha928@xxxxxxxxx
Cc: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
Changes from V4:
Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED
Add new ioctl description to api.txt
Documentation/virtual/kvm/api.txt | 12 ++++++++++++
arch/x86/include/asm/kvm_host.h | 2 ++
arch/x86/kvm/x86.c | 20 ++++++++++++++++++++
include/linux/kvm.h | 2 ++
4 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 7945b0b..0f7dd99 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1450,6 +1450,18 @@ is supported; 2 if the processor requires all virtual machines to have
an RMA, or 1 if the processor can use an RMA but doesn't require it,
because it supports the Virtual RMA (VRMA) facility.
+4.64 KVMCLOCK_GUEST_PAUSED
+
+Capability: basic
+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.
+
5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b4973f4..beb94c6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -672,6 +672,8 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
gpa_t addr, unsigned long *ret);
u8 kvm_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn);
+int kvm_set_guest_paused(struct kvm_vcpu *vcpu);
+
extern bool tdp_enabled;
u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c38efd7..1dab5fd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3295,6 +3295,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
goto out;
}
+ case KVMCLOCK_GUEST_PAUSED: {
+ r = kvm_set_guest_paused(vcpu);
+ break;
+ }
default:
r = -EINVAL;
}
@@ -6117,6 +6121,22 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
}
EXPORT_SYMBOL_GPL(kvm_task_switch);
+/*
+ * 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.
+ */
+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;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_set_guest_paused);
+
int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
struct kvm_sregs *sregs)
{
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index c3892fc..1d1ddef 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -762,6 +762,8 @@ 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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