Re: [Xen-devel] [PATCH v11 01/12] vpci: introduce basic handlers to trap accesses to the PCI config space

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 03/20/2018 03:15 PM, Roger Pau Monne wrote:
> This functionality is going to reside in vpci.c (and the corresponding
> vpci.h header), and should be arch-agnostic. The handlers introduced
> in this patch setup the basic functionality required in order to trap
> accesses to the PCI config space, and allow decoding the address and
> finding the corresponding handler that should handle the access
> (although no handlers are implemented).
>
> Note that the traps to the PCI IO ports registers (0xcf8/0xcfc) are
> setup inside of a x86 HVM file, since that's not shared with other
> arches.
>
> A new XEN_X86_EMU_VPCI x86 domain flag is added in order to signal Xen
> whether a domain should use the newly introduced vPCI handlers, this
> is only enabled for PVH Dom0 at the moment.
>
> A very simple user-space test is also provided, so that the basic
> functionality of the vPCI traps can be asserted. This has been proven
> quite helpful during development, since the logic to handle partial
> accesses or accesses that expand across multiple registers is not
> trivial.
>
> The handlers for the registers are added to a linked list that's keep
> sorted at all times. Both the read and write handlers support accesses
> that expand across multiple emulated registers and contain gaps not
> emulated.
>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
> [IO parts]
> Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

--
Julien Grall

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