On 20/07/2018 16:11, Zhang,Yi wrote: > Added Jiang,Dave, > > Ping for further review, comments. I need an Acked-by from the MM people to merge this. Jan, Dan? Paolo > > Thanks All > > Regards > Yi. > > > On 2018年07月11日 01:01, Zhang Yi wrote: >> For device specific memory space, when we move these area of pfn to >> memory zone, we will set the page reserved flag at that time, some of >> these reserved for device mmio, and some of these are not, such as >> NVDIMM pmem. >> >> Now, we map these dev_dax or fs_dax pages to kvm for DIMM/NVDIMM >> backend, since these pages are reserved. the check of >> kvm_is_reserved_pfn() misconceives those pages as MMIO. Therefor, we >> introduce 2 page map types, MEMORY_DEVICE_FS_DAX/MEMORY_DEVICE_DEV_DAX, >> to indentify these pages are from NVDIMM pmem. and let kvm treat these >> as normal pages. >> >> Without this patch, Many operations will be missed due to this >> mistreatment to pmem pages. For example, a page may not have chance to >> be unpinned for KVM guest(in kvm_release_pfn_clean); not able to be >> marked as dirty/accessed(in kvm_set_pfn_dirty/accessed) etc. >> >> V1: >> https://lkml.org/lkml/2018/7/4/91 >> >> V2: >> *Add documentation for MEMORY_DEVICE_DEV_DAX memory type in comment block >> *Add is_dax_page() in mm.h to differentiate the pages is from DAX device. >> *Remove the function kvm_is_nd_pfn(). >> >> Zhang Yi (4): >> kvm: remove redundant reserved page check >> mm: introduce memory type MEMORY_DEVICE_DEV_DAX >> mm: add a function to differentiate the pages is from DAX device >> memory >> kvm: add a check if pfn is from NVDIMM pmem. >> >> drivers/dax/pmem.c | 1 + >> include/linux/memremap.h | 9 +++++++++ >> include/linux/mm.h | 12 ++++++++++++ >> virt/kvm/kvm_main.c | 16 ++++++++-------- >> 4 files changed, 30 insertions(+), 8 deletions(-) >> > >
