Hi Jan,
On 09/26/2018 09:08 AM, Jan Beulich wrote:
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.
I am thinking to introduce p2m_mapping_owned. Or do we have a p2m_type
that we could re-use?
Cheers,
--
Julien Grall
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