diff options
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 20 | ||||
| -rw-r--r-- | Documentation/virtual/kvm/msr.txt | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 22 | ||||
| -rw-r--r-- | include/linux/kvm.h | 3 |
4 files changed, 49 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 6386f8c0482e..81ff39f6248d 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -1669,6 +1669,26 @@ at the memory location pointed to by "addr". The list of registers accessible using this interface is identical to the list in 4.64. +4.70 KVM_KVMCLOCK_CTRL + +Capability: KVM_CAP_KVMCLOCK_CTRL +Architectures: 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. The flag is part of the pvclock structure that +is shared between guest and host, specifically the second bit of the flags +field of the pvclock_vcpu_time_info structure. It will be set exclusively by +the host and read/cleared exclusively by the guest. The guest operation of +checking and clearing the flag must an atomic operation so +load-link/store-conditional, or equivalent must be used. There are two cases +where the guest will clear the flag: when the soft lockup watchdog timer resets +itself or when a soft lockup is detected. This ioctl can be called any time +after pausing the vcpu, but before it is resumed. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/Documentation/virtual/kvm/msr.txt b/Documentation/virtual/kvm/msr.txt index 50317809113d..96b41bd97523 100644 --- a/Documentation/virtual/kvm/msr.txt +++ b/Documentation/virtual/kvm/msr.txt @@ -109,6 +109,10 @@ MSR_KVM_SYSTEM_TIME_NEW: 0x4b564d01 0 | 24 | multiple cpus are guaranteed to | | be monotonic ------------------------------------------------------------- + | | guest vcpu has been paused by + 1 | N/A | the host + | | See 4.70 in api.txt + ------------------------------------------------------------- Availability of this MSR must be checked via bit 3 in 0x4000001 cpuid leaf prior to usage. diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 511031dcb9cc..99b738028fc0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2147,6 +2147,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_ASYNC_PF: case KVM_CAP_GET_TSC_KHZ: case KVM_CAP_PCI_2_3: + case KVM_CAP_KVMCLOCK_CTRL: r = 1; break; case KVM_CAP_COALESCED_MMIO: @@ -2597,6 +2598,23 @@ 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); + kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); + return 0; +} + long kvm_arch_vcpu_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { @@ -2873,6 +2891,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = vcpu->arch.virtual_tsc_khz; goto out; } + case KVM_KVMCLOCK_CTRL: { + r = kvm_set_guest_paused(vcpu); + goto out; + } default: r = -EINVAL; } diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 6c322a90b92f..7a9dd4b3dede 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -589,6 +589,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_S390_UCONTROL 73 #define KVM_CAP_SYNC_REGS 74 #define KVM_CAP_PCI_2_3 75 +#define KVM_CAP_KVMCLOCK_CTRL 76 #ifdef KVM_CAP_IRQ_ROUTING @@ -859,6 +860,8 @@ struct kvm_s390_ucas_mapping { /* Available with KVM_CAP_ONE_REG */ #define KVM_GET_ONE_REG _IOW(KVMIO, 0xab, struct kvm_one_reg) #define KVM_SET_ONE_REG _IOW(KVMIO, 0xac, struct kvm_one_reg) +/* VM is being stopped by host */ +#define KVM_KVMCLOCK_CTRL _IO(KVMIO, 0xad) #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0) #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1) |