From f848a5a8dcb655553423f77cc98909a04e64173d Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 31 Mar 2014 21:50:38 +0300 Subject: 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 Signed-off-by: Marcelo Tosatti --- include/uapi/linux/kvm.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/uapi/linux') 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 -- cgit v1.2.3-71-gd317