From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: [PATCH v2 6/6] Describe KVM_MSR_STEAL_TIME Date: Fri, 28 Jan 2011 14:52:20 -0500 Message-ID: <1296244340-15173-7-git-send-email-glommer@redhat.com> References: <1296244340-15173-1-git-send-email-glommer@redhat.com> Cc: linux-kernel@vger.kernel.org, aliguori@us.ibm.com To: kvm@vger.kernel.org Return-path: In-Reply-To: <1296244340-15173-1-git-send-email-glommer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org This patch adds documentation about usage of the newly introduced KVM_MSR_STEAL_TIME. Signed-off-by: Glauber Costa --- Documentation/kvm/msr.txt | 32 ++++++++++++++++++++++++++++++++ 1 files changed, 32 insertions(+), 0 deletions(-) diff --git a/Documentation/kvm/msr.txt b/Documentation/kvm/msr.txt index d079aed..7a2d223 100644 --- a/Documentation/kvm/msr.txt +++ b/Documentation/kvm/msr.txt @@ -185,3 +185,35 @@ MSR_KVM_ASYNC_PF_EN: 0x4b564d02 Currently type 2 APF will be always delivered on the same vcpu as type 1 was, but guest should not rely on that. + +MSR_KVM_STEAL_TIME: 0x4b564d03 + + data: 4-byte alignment physical address of a memory area which must be + in guest RAM, plus an enable bit in bit 0. This memory is expected to + hold a copy of the following structure: + + struct kvm_steal_time { + __u64 steal; + __u32 version; + __u32 flags; + __u32 pad[6]; + } + + whose data will be filled in by the hypervisor periodically. Only one + write, or registration, is needed for each VCPU. The interval between + updates of this structure is arbitrary and implementation-dependent. + The hypervisor may update this structure at any time it sees fit until + anything with bit0 == 0 is written to it. + + Fields have the following meanings: + + version: guest has to check version before and after grabbing + time information and check that they are both equal and even. + An odd version indicates an in-progress update. + + flags: At this point, always zero. May be used to indicate + changes in this structure in the future. + + steal: the amount of time in which this vCPU did not run, in + nanoseconds. + -- 1.7.2.3