summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorJoerg Roedel <joerg.roedel@amd.com>2011-03-25 09:44:51 +0100
committerAvi Kivity <avi@redhat.com>2011-05-11 07:57:06 -0400
commit92a1f12d2598f429bd8639e21d89305e787115c5 (patch)
tree48a6b7d6c50b5583b5163185dd097db100a471c6 /Documentation
parent857e40999e35906baa367a79137019912cfb5434 (diff)
downloadop-kernel-dev-92a1f12d2598f429bd8639e21d89305e787115c5.zip
op-kernel-dev-92a1f12d2598f429bd8639e21d89305e787115c5.tar.gz
KVM: X86: Implement userspace interface to set virtual_tsc_khz
This patch implements two new vm-ioctls to get and set the virtual_tsc_khz if the machine supports tsc-scaling. Setting the tsc-frequency is only possible before userspace creates any vcpu. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kvm/api.txt23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 9bef4e4..1b9eaa7 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -1263,6 +1263,29 @@ struct kvm_assigned_msix_entry {
__u16 padding[3];
};
+4.54 KVM_SET_TSC_KHZ
+
+Capability: KVM_CAP_TSC_CONTROL
+Architectures: x86
+Type: vcpu ioctl
+Parameters: virtual tsc_khz
+Returns: 0 on success, -1 on error
+
+Specifies the tsc frequency for the virtual machine. The unit of the
+frequency is KHz.
+
+4.55 KVM_GET_TSC_KHZ
+
+Capability: KVM_CAP_GET_TSC_KHZ
+Architectures: x86
+Type: vcpu ioctl
+Parameters: none
+Returns: virtual tsc-khz on success, negative value on error
+
+Returns the tsc frequency of the guest. The unit of the return value is
+KHz. If the host has unstable tsc this ioctl returns -EIO instead as an
+error.
+
5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by
OpenPOWER on IntegriCloud