2018-02-01 16:48+0300, Roman Kagan:
> 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@xxxxxxxxxxxxx>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
> Documentation/virtual/kvm/api.txt | 31 +++++++++++
> arch/x86/include/asm/kvm_host.h | 2 +
> arch/x86/include/uapi/asm/hyperv.h | 2 +
> arch/x86/kvm/hyperv.h | 1 +
> include/uapi/linux/kvm.h | 13 +++++
> arch/x86/kvm/hyperv.c | 103 ++++++++++++++++++++++++++++++++++++-
> arch/x86/kvm/x86.c | 10 ++++
> 7 files changed, 161 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
> index 1a5bfead93b4..f9ed479d479c 100644
> --- a/arch/x86/include/uapi/asm/hyperv.h
> +++ b/arch/x86/include/uapi/asm/hyperv.h
> @@ -276,7 +276,9 @@ enum HV_GENERIC_SET_FORMAT {
> #define HV_STATUS_INVALID_HYPERCALL_CODE 2
> #define HV_STATUS_INVALID_HYPERCALL_INPUT 3
> #define HV_STATUS_INVALID_ALIGNMENT 4
> +#define HV_STATUS_INVALID_PARAMETER 5
> #define HV_STATUS_INSUFFICIENT_MEMORY 11
> +#define HV_STATUS_INVALID_PORT_ID 17
> #define HV_STATUS_INVALID_CONNECTION_ID 18
> #define HV_STATUS_INSUFFICIENT_BUFFERS 19
>
x86/hyperv maintainers,
are you ok with this hunk going through the kvm tree?
Thanks.
