diff options
author | Eric B Munson <emunson@mgebm.net> | 2012-03-10 14:37:27 -0500 |
---|---|---|
committer | Avi Kivity <avi@redhat.com> | 2012-04-08 05:49:01 -0400 |
commit | 1c0b28c2a46d98cd258d96b8c222144b22876c46 (patch) | |
tree | 68c5b4f6a74e3b245dd994752fdc9005075b485c /Documentation/virtual | |
parent | 3b5d56b9317fa7b5407dff1aa7b115bf6cdbd494 (diff) |
KVM: x86: Add ioctl for KVM_KVMCLOCK_CTRL
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@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r-- | Documentation/virtual/kvm/api.txt | 20 | ||||
-rw-r--r-- | Documentation/virtual/kvm/msr.txt | 4 |
2 files changed, 24 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". | |||
1669 | The list of registers accessible using this interface is identical to the | 1669 | The list of registers accessible using this interface is identical to the |
1670 | list in 4.64. | 1670 | list in 4.64. |
1671 | 1671 | ||
1672 | 4.70 KVM_KVMCLOCK_CTRL | ||
1673 | |||
1674 | Capability: KVM_CAP_KVMCLOCK_CTRL | ||
1675 | Architectures: Any that implement pvclocks (currently x86 only) | ||
1676 | Type: vcpu ioctl | ||
1677 | Parameters: None | ||
1678 | Returns: 0 on success, -1 on error | ||
1679 | |||
1680 | This signals to the host kernel that the specified guest is being paused by | ||
1681 | userspace. The host will set a flag in the pvclock structure that is checked | ||
1682 | from the soft lockup watchdog. The flag is part of the pvclock structure that | ||
1683 | is shared between guest and host, specifically the second bit of the flags | ||
1684 | field of the pvclock_vcpu_time_info structure. It will be set exclusively by | ||
1685 | the host and read/cleared exclusively by the guest. The guest operation of | ||
1686 | checking and clearing the flag must an atomic operation so | ||
1687 | load-link/store-conditional, or equivalent must be used. There are two cases | ||
1688 | where the guest will clear the flag: when the soft lockup watchdog timer resets | ||
1689 | itself or when a soft lockup is detected. This ioctl can be called any time | ||
1690 | after pausing the vcpu, but before it is resumed. | ||
1691 | |||
1672 | 5. The kvm_run structure | 1692 | 5. The kvm_run structure |
1673 | 1693 | ||
1674 | Application code obtains a pointer to the kvm_run structure by | 1694 | 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 | |||
109 | 0 | 24 | multiple cpus are guaranteed to | 109 | 0 | 24 | multiple cpus are guaranteed to |
110 | | | be monotonic | 110 | | | be monotonic |
111 | ------------------------------------------------------------- | 111 | ------------------------------------------------------------- |
112 | | | guest vcpu has been paused by | ||
113 | 1 | N/A | the host | ||
114 | | | See 4.70 in api.txt | ||
115 | ------------------------------------------------------------- | ||
112 | 116 | ||
113 | Availability of this MSR must be checked via bit 3 in 0x4000001 cpuid | 117 | Availability of this MSR must be checked via bit 3 in 0x4000001 cpuid |
114 | leaf prior to usage. | 118 | leaf prior to usage. |