Introduce a handler for the PCI status register, with ability to mask
the capabilities bit. The status register contains RsvdZ bits,
read-only bits, and write-1-to-clear bits. Additionally, we use RsvdP to
mask the capabilities bit. Introduce bitmasks to handle these in vPCI.
If a bit in the bitmask is set, then the special meaning applies:
ro_mask: read normal, guest write ignore (preserve on write to hardware)
rw1c_mask: read normal, write 1 to clear
rsvdp_mask: read as zero, guest write ignore (preserve on write to hardware)
rsvdz_mask: read as zero, guest write ignore (write zero to hardware)
The RO/RW1C/RsvdP/RsvdZ naming and definitions were borrowed from the
PCI Express Base 6.1 specification. RsvdP/RsvdZ bits help Xen enforce
our view of the world. Xen preserves the value of read-only bits on
write to hardware, discarding the guests write value. This is done in
case hardware wrongly implements R/O bits as R/W.
The mask_cap_list flag will be set in a follow-on change.
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
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@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
[IO parts]
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
[ARM]
Acked-by: Julien Grall <julien.grall@arm.com>
[Tools]
Acked-by: Wei Liu <wei.liu2@citrix.com>
Stewart Hildebrand
Roger Pau Monne