Re: [RFC PATCH v1 11/25] hw/xen: Pass grant ref to gnttab unmap operation

[Paul Durrant <xadimgnik@gmail.com>]

On 02/03/2023 15:34, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> The previous commit introduced redirectable gnttab operations fairly
> much like-for-like, with the exception of the extra arguments to the
> ->open() call which were always NULL/0 anyway.
> 
> This *changes* the arguments to the ->unmap() operation to include the
> original ref# that was mapped. Under real Xen it isn't necessary; all we
> need to do from QEMU is munmap(), then the kernel will release the grant,
> and Xen does the tracking/refcounting for the guest.
> 
> When we have emulated grant tables though, we need to do all that for
> ourselves. So let's have the back ends keep track of what they mapped
> and pass it in to the ->unmap() method for us.
> 
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   hw/9pfs/xen-9p-backend.c            |  7 ++++---
>   hw/block/dataplane/xen-block.c      |  1 +
>   hw/char/xen_console.c               |  2 +-
>   hw/net/xen_nic.c                    | 13 ++++++++-----
>   hw/usb/xen-usb.c                    | 21 ++++++++++++++++-----
>   hw/xen/xen-bus.c                    |  4 ++--
>   hw/xen/xen-legacy-backend.c         |  4 ++--
>   hw/xen/xen-operations.c             |  9 ++++++++-
>   include/hw/xen/xen-bus.h            |  2 +-
>   include/hw/xen/xen-legacy-backend.h |  6 +++---
>   include/hw/xen/xen_backend_ops.h    |  7 ++++---
>   11 files changed, 50 insertions(+), 26 deletions(-)
> 

Reviewed-by: Paul Durrant <paul@xen.org>