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| author | Michael S. Tsirkin <mst@redhat.com> | 2014-03-31 22:50:38 +0400 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2014-04-17 21:01:42 +0400 |
| commit | f848a5a8dcb655553423f77cc98909a04e64173d (patch) | |
| tree | 02e212c8eeeb52e74876408bb5e7e5d2febae379 /include/uapi | |
| parent | cd9ae5fe47dfb9820976c3c38c70f4b07a5a1c36 (diff) | |
| download | linux-f848a5a8dcb655553423f77cc98909a04e64173d.tar.xz | |
KVM: support any-length wildcard ioeventfd
It is sometimes benefitial to ignore IO size, and only match on address.
In hindsight this would have been a better default than matching length
when KVM_IOEVENTFD_FLAG_DATAMATCH is not set, In particular, this kind
of access can be optimized on VMX: there no need to do page lookups.
This can currently be done with many ioeventfds but in a suboptimal way.
However we can't change kernel/userspace ABI without risk of breaking
some applications.
Use len = 0 to mean "ignore length for matching" in a more optimal way.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/kvm.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a8f4ee5d2e82..39098a61f41c 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -529,7 +529,7 @@ enum { struct kvm_ioeventfd { __u64 datamatch; __u64 addr; /* legal pio/mmio address */ - __u32 len; /* 1, 2, 4, or 8 bytes */ + __u32 len; /* 1, 2, 4, or 8 bytes; or 0 to ignore length */ __s32 fd; __u32 flags; __u8 pad[36]; @@ -743,6 +743,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_IOAPIC_POLARITY_IGNORED 97 #define KVM_CAP_ENABLE_CAP_VM 98 #define KVM_CAP_S390_IRQCHIP 99 +#define KVM_CAP_IOEVENTFD_NO_LENGTH 100 #ifdef KVM_CAP_IRQ_ROUTING |