From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH v9 2/2] kvm: x86: hyperv: guest->host event signaling via
 eventfd
Date: Thu, 1 Feb 2018 15:56:45 +0100
Message-ID: <20180201145645.GC26932@flask>
References: <20180201134832.17259-1-rkagan@virtuozzo.com>
 <20180201134832.17259-3-rkagan@virtuozzo.com>
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Cc: Roman Kagan <rkagan@virtuozzo.com>, kvm@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        "Denis V. Lunev" <den@openvz.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        David Hildenbrand <david@redhat.com>
To: "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>
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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@virtuozzo.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
>  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.