> -----Original Message----- > From: Jan Beulich [mailto:jbeul...@suse.com] > Sent: 26 September 2018 09:09 > To: Julien Grall <julien.gr...@arm.com>; Paul Durrant > <paul.durr...@citrix.com> > Cc: Andrew Cooper <andrew.coop...@citrix.com>; Roger Pau Monne > <roger....@citrix.com>; Stefano Stabellini <sstabell...@kernel.org>; xen- > devel <xen-devel@lists.xenproject.org> > Subject: Re: IOREQ server on Arm > > >>> On 26.09.18 at 00:39, <julien.gr...@arm.com> wrote: > > Hi Paul, > > > > I am looking at porting the IOREQ server infrastructure on Arm. I didn't > > need much modification to make it run for Arm. Although, the > > implementation could be simplified over the x86 implementation. > > > > I noticed some issue while trying to implement the hypercall > > XENMEM_acquire_resource. Per my understanding, all the page mapped via > > that hypercall will use the type p2m_mapping_foreign. > > > > This will result to trigger the ASSERT(fdom != dom) in get_page_from_gfn > > (asm-arm/p2m.h) because the IOREQ page has been allocated to the > > emulator domain and mapped to it. AFAICT x86 has the same assert in > > p2m_get_page_from_gfn(...). > > > > IHMO, the ASSERT makes sense because you are only meant to map page > > belonging to other domain with that type. > > > > So I am wondering whether IOREQ server running in PVH Dom0 has been > > tested? What would be the best course of action to fix the issue? > > I think the p2m type needs to be chosen based on > XENMEM_rsrc_acq_caller_owned. >
Yes, that's correct. There is a FIXME clause in acquire_resource so that that only caller owned resources can be mapped by HVM/PVH domains. Thus the new call can be used for IOREQ server pages, but not grant frames. Paul > Jan > _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
