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| author | Roman Kagan <rkagan@virtuozzo.com> | 2018-02-01 16:48:32 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2018-03-06 18:40:36 +0100 |
| commit | faeb7833eee0d6afe0ecb6bdfa6042556c2c352e (patch) | |
| tree | 894003ec025273ac159e9a57f9fc98c2dac180e0 /include | |
| parent | cbc0236a4b3e6a64f5b8bee27b530c7f8bee8d56 (diff) | |
| download | linux-faeb7833eee0d6afe0ecb6bdfa6042556c2c352e.tar.gz linux-faeb7833eee0d6afe0ecb6bdfa6042556c2c352e.tar.bz2 linux-faeb7833eee0d6afe0ecb6bdfa6042556c2c352e.zip | |
kvm: x86: hyperv: guest->host event signaling via eventfd
In Hyper-V, the fast guest->host notification mechanism is the
SIGNAL_EVENT hypercall, with a single parameter of the connection ID to
signal.
Currently this hypercall incurs a user exit and requires the userspace
to decode the parameters and trigger the notification of the potentially
different I/O context.
To avoid the costly user exit, process this hypercall and signal the
corresponding eventfd in KVM, similar to ioeventfd. The association
between the connection id and the eventfd is established via the newly
introduced KVM_HYPERV_EVENTFD ioctl, and maintained in an
(srcu-protected) IDR.
Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[asm/hyperv.h changes approved by KY Srinivasan. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/kvm.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 7b26d4b0b052..2d2d926113ba 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -936,6 +936,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_PPC_GET_CPU_CHAR 151 #define KVM_CAP_S390_BPB 152 #define KVM_CAP_GET_MSR_FEATURES 153 +#define KVM_CAP_HYPERV_EVENTFD 154 #ifdef KVM_CAP_IRQ_ROUTING @@ -1375,6 +1376,10 @@ struct kvm_enc_region { #define KVM_MEMORY_ENCRYPT_REG_REGION _IOR(KVMIO, 0xbb, struct kvm_enc_region) #define KVM_MEMORY_ENCRYPT_UNREG_REGION _IOR(KVMIO, 0xbc, struct kvm_enc_region) +/* Available with KVM_CAP_HYPERV_EVENTFD */ +#define KVM_HYPERV_EVENTFD _IOW(KVMIO, 0xbd, struct kvm_hyperv_eventfd) + + /* Secure Encrypted Virtualization command */ enum sev_cmd_id { /* Guest initialization commands */ @@ -1515,4 +1520,14 @@ struct kvm_assigned_msix_entry { #define KVM_ARM_DEV_EL1_PTIMER (1 << 1) #define KVM_ARM_DEV_PMU (1 << 2) +struct kvm_hyperv_eventfd { + __u32 conn_id; + __s32 fd; + __u32 flags; + __u32 padding[3]; +}; + +#define KVM_HYPERV_CONN_ID_MASK 0x00ffffff +#define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) + #endif /* __LINUX_KVM_H */ |