[PATCH 3/4 V11] Add ioctl for KVMCLOCK_GUEST_STOPPED
From: Eric B Munson <hidden>
Date: 2012-01-31 15:35:47
Also in:
kvm, lkml
Subsystem:
documentation, kernel virtual machine (kvm), kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Jonathan Corbet, Paolo Bonzini, Sean Christopherson, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <redacted> Cc: mingo@redhat.com Cc: hpa@zytor.com Cc: ryanh@linux.vnet.ibm.com Cc: aliguori@us.ibm.com Cc: mtosatti@redhat.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from V10: Return the ioctl to per vcpu instead of per vm Changes from V9: Use kvm_for_each_vcpu to iterate online vcpu's Changes from V8: Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu 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 14d6cad..c9cabba 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)
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1.7.5.4