path: root/Documentation
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authorAlexander Graf <agraf@suse.de>2014-07-14 18:33:08 +0200
committerChristoffer Dall <christoffer.dall@linaro.org>2014-10-02 17:19:06 +0200
commitc509fab667c6a02b0763a4343c73d134c6a09328 (patch)
tree1a318327cf3054ff33757d242bc237b17db04deb /Documentation
parent7b6de249336851f2fb8515b2f428bc9e56a8dbb1 (diff)
KVM: Allow KVM_CHECK_EXTENSION on the vm fd
The KVM_CHECK_EXTENSION is only available on the kvm fd today. Unfortunately on PPC some of the capabilities change depending on the way a VM was created. So instead we need a way to expose capabilities as VM ioctl, so that we can see which VM type we're using (HV or PR). To enable this, add the KVM_CHECK_EXTENSION ioctl to our vm ioctl portfolio. Signed-off-by: Alexander Graf <agraf@suse.de> Acked-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit 92b591a4c46b103ebd3fc0d03a084e1efd331253) Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'Documentation')
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 8d135672b69a..257a1f1eecc7 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -148,9 +148,9 @@ of banks, as set via the KVM_X86_SETUP_MCE ioctl.
-Capability: basic
+Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl
Architectures: all
-Type: system ioctl
+Type: system ioctl, vm ioctl
Parameters: extension identifier (KVM_CAP_*)
Returns: 0 if unsupported; 1 (or some other positive integer) if supported
@@ -160,6 +160,9 @@ receives an integer that describes the extension availability.
Generally 0 means no and 1 means yes, but some extensions may report
additional information in the integer return value.
+Based on their initialization different VMs may have different capabilities.
+It is thus encouraged to use the vm ioctl to query for capabilities (available
+with KVM_CAP_CHECK_EXTENSION_VM on the vm fd)