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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 Copies the input argument into the the Local APIC registers. The data format
and layout are the same as documented in the architecture manual. 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 5. The kvm_run structure
Application code obtains a pointer to the kvm_run structure by Application code obtains a pointer to the kvm_run structure by