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KVM: Document KVM_IOEVENTFD

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Document KVM_IOEVENTFD that can be used to receive
notifications of PIO/MMIO events without triggering
an exit.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Sasha Levin 2011-05-28 14:12:30 +03:00 committed by Avi Kivity
parent 823e396558
commit 55399a02e9
1 changed files with 30 additions and 0 deletions
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30
Documentation/virtual/kvm/api.txt
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@ -1323,6 +1323,36 @@ struct kvm_lapic_state {
Copies the input argument into the the Local APIC registers. The data format
and layout are the same as documented in the architecture manual.
4.56 KVM_IOEVENTFD
Capability: KVM_CAP_IOEVENTFD
Architectures: all
Type: vm ioctl
Parameters: struct kvm_ioeventfd (in)
Returns: 0 on success, !0 on error
This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address
within the guest. A guest write in the registered address will signal the
provided event instead of triggering an exit.
struct kvm_ioeventfd {
__u64 datamatch;
__u64 addr; /* legal pio/mmio address */
__u32 len; /* 1, 2, 4, or 8 bytes */
__s32 fd;
__u32 flags;
__u8 pad[36];
};
The following flags are defined:
#define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
#define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
#define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
If datamatch flag is set, the event will be signaled only if the written value
to the registered address is equal to datamatch in struct kvm_ioeventfd.
5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by