[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6 0/2] add new p2m type class and new p2m type
Hi Tim & Jan, Thank you very much for your review.And could you please also help me about how to get an ACK? I'm not sure what's the next action I need to take. :-) B.R. Yu On 12/6/2014 11:55 AM, Yu Zhang wrote: XenGT (Intel Graphics Virtualization technology, please refer to https://01.org/xen/blogs/srclarkx/2013/graphics-virtualization- xengt) driver runs inside Dom0 as a virtual graphics device model, and needs to trap and emulate the guest's write operations to some specific memory pages, like memory pages used by guest graphics driver as PPGTT(per-process graphics translation table). We added a new p2m type, p2m_mmio_write_dm, to trap and emulate the write operations on these graphic page tables. Handling of this new p2m type are similar with existing p2m_ram_ro in most condition checks, with only difference on final policy of emulation vs. drop. For p2m_ram_ro types, write operations will not trigger the device model, and will be discarded later in __hvm_copy(); while for the p2m_mmio_write_dm type pages, writes will go to the device model via ioreq-server. Previously, the conclusion in our v3 patch review is to provide a more generalized HVMOP_map_io_range_to_ioreq_server hypercall, by seperating rangesets inside a ioreq server to read-protected/write- protected/both-prtected. Yet, after offline discussion with Paul, we believe a more simplified solution may suffice. We can keep the existing HVMOP_map_io_range_to_ioreq_server hypercall, and let the user decide whether or not a p2m type change is necessary, because in most cases the emulator will already use the p2m_mmio_dm type. Changes from v5: - Stricter type checks for p2m type transitions; - One code style change. Changes from v4: - A new p2m type class, P2M_DISCARD_WRITE_TYPES, is added; - A new predicate, p2m_is_discard_write, is used in __hvm_copy()/ __hvm_clear()/emulate_gva_to_mfn()/hvm_hap_nested_page_fault(), to discard the write operations; - The new p2m type, p2m_mmio_write_dm, is added to P2M_RO_TYPES; - Coding style changes; Changes from v3: - Use the existing HVMOP_map_io_range_to_ioreq_server hypercall to add write protected range; - Modify the HVMOP_set_mem_type hypercall to support the new p2m type for this range. Changes from v2: - Remove excute attribute of the new p2m type p2m_mmio_write_dm; - Use existing rangeset for keeping the write protection page range instead of introducing hash table; - Some code style fix. Changes from v1: - Changes the new p2m type name from p2m_ram_wp to p2m_mmio_write_dm. This means that we treat the pages as a special mmio range instead of ram; - Move macros to c file since only this file is using them. - Address various comments from Jan. Yu Zhang (2): Add a new p2m type class - P2M_DISCARD_WRITE_TYPES add a new p2m type - p2m_mmio_write_dm xen/arch/x86/hvm/hvm.c | 25 ++++++++++--------------- xen/arch/x86/mm/p2m-ept.c | 1 + xen/arch/x86/mm/p2m-pt.c | 1 + xen/arch/x86/mm/shadow/multi.c | 2 +- xen/include/asm-x86/p2m.h | 9 ++++++++- xen/include/public/hvm/hvm_op.h | 1 + 6 files changed, 22 insertions(+), 17 deletions(-) _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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