Re: [RFC 2/2] KVM: add initial support for ioregionfd blocking read/write operations

[Jason Wang <jasowang@xxxxxxxxxx>]

On 2020/12/29 下午6:02, Elena Afanasova wrote:
> Signed-off-by: Elena Afanasova<eafanasova@xxxxxxxxx>
> ---
>   virt/kvm/ioregion.c | 157 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 157 insertions(+)
>
> diff --git a/virt/kvm/ioregion.c b/virt/kvm/ioregion.c
> index a200c3761343..8523f4126337 100644
> --- a/virt/kvm/ioregion.c
> +++ b/virt/kvm/ioregion.c
> @@ -4,6 +4,33 @@
>   #include <kvm/iodev.h>
>   #include "eventfd.h"
>   
> +/* Wire protocol */
> +struct ioregionfd_cmd {
> +	__u32 info;
> +	__u32 padding;
> +	__u64 user_data;
> +	__u64 offset;
> +	__u64 data;
> +};
> +


I wonder do we need a seq in the protocol. It might be useful if we 
allow a pair of file descriptors to be used for multiple different ranges.

Thanks


> +struct ioregionfd_resp {
> +	__u64 data;
> +	__u8 pad[24];
> +};