Re: [Xen-devel] [PATCH v2] pci: clear {host/guest}_maskall field on assign

[Chao Gao <chao.gao@xxxxxxxxx>]

On Wed, Oct 09, 2019 at 10:33:21AM +0200, Roger Pau Monne wrote:
>The current implementation of host_maskall makes it sticky across
>assign and deassign calls, which means that once a guest forces Xen to
>set host_maskall the maskall bit is not going to be cleared until a
>call to PHYSDEVOP_prepare_msix is performed. Such call however
>shouldn't be part of the normal flow when doing PCI passthrough, and
>hence the flag needs to be cleared when assigning in order to prevent
>host_maskall being carried over from previous assignations.
>
>Note that the entry maskbit is reset when the msix capability is
>initialized, and the guest_maskall field is also cleared so that the
>hardware value matches Xen's internal state (hardware maskall =
>host_maskall | guest_maskall).
>
>Also note that doing the reset of host_maskall there would allow the
>guest to reset such field by enabling and disabling MSIX, which is not
>intended.
>
>Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
>---
>Cc: Chao Gao <chao.gao@xxxxxxxxx>
>Cc: "Spassov, Stanislav" <stanspas@xxxxxxxxx>
>Cc: Pasi Kärkkäinen <pasik@xxxxxx>
>---
>Chao, Stanislav, can you please check if this patch fixes your
>issues?

Tested-by: Chao Gao <chao.gao@xxxxxxxxx>

I got the assertion failure below when starting xencommons with the
newest staging:

Setting domain 0 name, domid and JSON config...
xen-init-dom0: _libxl_types.c:2163: libxl_domain_build_info_init_type: 
Assertion `p->type == LIBXL_DOMAIN_TYPE_INVALID' failed.
/etc/init.d/xencommons: line 54:  2006 Aborted                 (core dumped) 
${LIBEXEC_BIN}/xen-init-dom0 ${XEN_DOM0_UUID}

It should be irrelated to this patch. So I apply this patch on
cd93953538aac and it works.

Thanks
Chao

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel