From dab4b911a5327859bb8f969249c6978c26cd4853 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Sun, 6 Dec 2009 18:24:15 +0100 Subject: KVM: x86: Extend KVM_SET_VCPU_EVENTS with selective updates User space may not want to overwrite asynchronously changing VCPU event states on write-back. So allow to skip nmi.pending and sipi_vector by setting corresponding bits in the flags field of kvm_vcpu_events. [avi: advertise the bits in KVM_GET_VCPU_EVENTS] Signed-off-by: Jan Kiszka Signed-off-by: Avi Kivity --- Documentation/kvm/api.txt | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index e1a114161027..2811e452f756 100644 --- a/Documentation/kvm/api.txt +++ b/Documentation/kvm/api.txt @@ -685,7 +685,7 @@ struct kvm_vcpu_events { __u8 pad; } nmi; __u32 sipi_vector; - __u32 flags; /* must be zero */ + __u32 flags; }; 4.30 KVM_SET_VCPU_EVENTS @@ -701,6 +701,14 @@ vcpu. See KVM_GET_VCPU_EVENTS for the data structure. +Fields that may be modified asynchronously by running VCPUs can be excluded +from the update. These fields are nmi.pending and sipi_vector. Keep the +corresponding bits in the flags field cleared to suppress overwriting the +current in-kernel state. The bits are: + +KVM_VCPUEVENT_VALID_NMI_PENDING - transfer nmi.pending to the kernel +KVM_VCPUEVENT_VALID_SIPI_VECTOR - transfer sipi_vector + 5. The kvm_run structure -- cgit v1.2.3-59-g8ed1b