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SubjectRe: [PATCH V2 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio
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Added Jiang,Dave,

Ping for further review, comments.

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(-)
>

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