* [PATCH 0/3] Fix kvm misconceives NVDIMM pages as reserved mmio @ 2018-07-04 15:30 Zhang Yi 2018-07-04 15:30 ` [PATCH 1/3] kvm: remove redundant reserved page check Zhang Yi ` (2 more replies) 0 siblings, 3 replies; 11+ messages in thread From: Zhang Yi @ 2018-07-04 15:30 UTC (permalink / raw) To: kvm, linux-kernel, linux-nvdimm, pbonzini, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar 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. Zhang Yi (3): kvm: remove redundant reserved page check mm: introduce memory type MEMORY_DEVICE_DEV_DAX kvm: add a function to check if page is from NVDIMM pmem. drivers/dax/pmem.c | 1 + include/linux/memremap.h | 1 + virt/kvm/kvm_main.c | 25 +++++++++++++++++-------- 3 files changed, 19 insertions(+), 8 deletions(-) -- 2.7.4 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 1/3] kvm: remove redundant reserved page check 2018-07-04 15:30 [PATCH 0/3] Fix kvm misconceives NVDIMM pages as reserved mmio Zhang Yi @ 2018-07-04 15:30 ` Zhang Yi 2018-07-04 15:30 ` [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Zhang Yi 2018-07-04 15:30 ` [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem Zhang Yi 2 siblings, 0 replies; 11+ messages in thread From: Zhang Yi @ 2018-07-04 15:30 UTC (permalink / raw) To: kvm, linux-kernel, linux-nvdimm, pbonzini, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar PageReserved() is already checked inside kvm_is_reserved_pfn(), remove it from kvm_set_pfn_dirty(). Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> --- virt/kvm/kvm_main.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c7b2e92..afb2e6e 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1673,12 +1673,8 @@ EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty); void kvm_set_pfn_dirty(kvm_pfn_t pfn) { - if (!kvm_is_reserved_pfn(pfn)) { - struct page *page = pfn_to_page(pfn); - - if (!PageReserved(page)) - SetPageDirty(page); - } + if (!kvm_is_reserved_pfn(pfn)) + SetPageDirty(pfn_to_page(pfn)); } EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty); -- 2.7.4 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX 2018-07-04 15:30 [PATCH 0/3] Fix kvm misconceives NVDIMM pages as reserved mmio Zhang Yi 2018-07-04 15:30 ` [PATCH 1/3] kvm: remove redundant reserved page check Zhang Yi @ 2018-07-04 15:30 ` Zhang Yi 2018-07-04 14:50 ` Dan Williams 2018-07-04 15:30 ` [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem Zhang Yi 2 siblings, 1 reply; 11+ messages in thread From: Zhang Yi @ 2018-07-04 15:30 UTC (permalink / raw) To: kvm, linux-kernel, linux-nvdimm, pbonzini, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar Currently, NVDIMM pages will be marked 'PageReserved'. However, unlike other reserved PFNs, pages on NVDIMM shall still behave like normal ones in many cases, i.e. when used as backend memory of KVM guest. This patch introduces a new memory type, MEMORY_DEVICE_DEV_DAX. Together with the existing type MEMORY_DEVICE_FS_DAX, we can differentiate the pages on NVDIMM with the normal reserved pages. Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> --- drivers/dax/pmem.c | 1 + include/linux/memremap.h | 1 + 2 files changed, 2 insertions(+) diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index fd49b24..fb3f363 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -111,6 +111,7 @@ static int dax_pmem_probe(struct device *dev) return rc; dax_pmem->pgmap.ref = &dax_pmem->ref; + dax_pmem->pgmap.type = MEMORY_DEVICE_DEV_DAX; addr = devm_memremap_pages(dev, &dax_pmem->pgmap); if (IS_ERR(addr)) return PTR_ERR(addr); diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 5ebfff6..4127bf7 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -58,6 +58,7 @@ enum memory_type { MEMORY_DEVICE_PRIVATE = 1, MEMORY_DEVICE_PUBLIC, MEMORY_DEVICE_FS_DAX, + MEMORY_DEVICE_DEV_DAX, }; /* -- 2.7.4 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX 2018-07-04 15:30 ` [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Zhang Yi @ 2018-07-04 14:50 ` Dan Williams 2018-07-05 13:20 ` zhangyi6 0 siblings, 1 reply; 11+ messages in thread From: Dan Williams @ 2018-07-04 14:50 UTC (permalink / raw) To: Zhang Yi Cc: Jan Kara, Zhang, Yu C, KVM list, linux-nvdimm, rkrcmar, Linux Kernel Mailing List, Linux MM, Paolo Bonzini, Christoph Hellwig, Zhang, Yi Z On Wed, Jul 4, 2018 at 8:30 AM, Zhang Yi <yi.z.zhang@linux.intel.com> wrote: > Currently, NVDIMM pages will be marked 'PageReserved'. However, unlike > other reserved PFNs, pages on NVDIMM shall still behave like normal ones > in many cases, i.e. when used as backend memory of KVM guest. This patch > introduces a new memory type, MEMORY_DEVICE_DEV_DAX. Together with the > existing type MEMORY_DEVICE_FS_DAX, we can differentiate the pages on > NVDIMM with the normal reserved pages. > > Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> > Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> > --- > drivers/dax/pmem.c | 1 + > include/linux/memremap.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c > index fd49b24..fb3f363 100644 > --- a/drivers/dax/pmem.c > +++ b/drivers/dax/pmem.c > @@ -111,6 +111,7 @@ static int dax_pmem_probe(struct device *dev) > return rc; > > dax_pmem->pgmap.ref = &dax_pmem->ref; > + dax_pmem->pgmap.type = MEMORY_DEVICE_DEV_DAX; > addr = devm_memremap_pages(dev, &dax_pmem->pgmap); > if (IS_ERR(addr)) > return PTR_ERR(addr); > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 5ebfff6..4127bf7 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -58,6 +58,7 @@ enum memory_type { > MEMORY_DEVICE_PRIVATE = 1, > MEMORY_DEVICE_PUBLIC, > MEMORY_DEVICE_FS_DAX, > + MEMORY_DEVICE_DEV_DAX, Please add documentation for this new type to the comment block about this definition. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX 2018-07-04 14:50 ` Dan Williams @ 2018-07-05 13:20 ` zhangyi6 0 siblings, 0 replies; 11+ messages in thread From: zhangyi6 @ 2018-07-05 13:20 UTC (permalink / raw) To: Dan Williams, Zhang Yi Cc: Jan Kara, Zhang, Yu C, KVM list, linux-nvdimm, rkrcmar, Linux Kernel Mailing List, Linux MM, Paolo Bonzini, Christoph Hellwig On 2018年07月04日 22:50, Dan Williams wrote: > On Wed, Jul 4, 2018 at 8:30 AM, Zhang Yi <yi.z.zhang@linux.intel.com> wrote: >> Currently, NVDIMM pages will be marked 'PageReserved'. However, unlike >> other reserved PFNs, pages on NVDIMM shall still behave like normal ones >> in many cases, i.e. when used as backend memory of KVM guest. This patch >> introduces a new memory type, MEMORY_DEVICE_DEV_DAX. Together with the >> existing type MEMORY_DEVICE_FS_DAX, we can differentiate the pages on >> NVDIMM with the normal reserved pages. >> >> Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> >> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> >> --- >> drivers/dax/pmem.c | 1 + >> include/linux/memremap.h | 1 + >> 2 files changed, 2 insertions(+) >> >> diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c >> index fd49b24..fb3f363 100644 >> --- a/drivers/dax/pmem.c >> +++ b/drivers/dax/pmem.c >> @@ -111,6 +111,7 @@ static int dax_pmem_probe(struct device *dev) >> return rc; >> >> dax_pmem->pgmap.ref = &dax_pmem->ref; >> + dax_pmem->pgmap.type = MEMORY_DEVICE_DEV_DAX; >> addr = devm_memremap_pages(dev, &dax_pmem->pgmap); >> if (IS_ERR(addr)) >> return PTR_ERR(addr); >> diff --git a/include/linux/memremap.h b/include/linux/memremap.h >> index 5ebfff6..4127bf7 100644 >> --- a/include/linux/memremap.h >> +++ b/include/linux/memremap.h >> @@ -58,6 +58,7 @@ enum memory_type { >> MEMORY_DEVICE_PRIVATE = 1, >> MEMORY_DEVICE_PUBLIC, >> MEMORY_DEVICE_FS_DAX, >> + MEMORY_DEVICE_DEV_DAX, > Please add documentation for this new type to the comment block about > this definition. Thanks for your comments Dan, Will add it in next version, Regards Yi. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-04 15:30 [PATCH 0/3] Fix kvm misconceives NVDIMM pages as reserved mmio Zhang Yi 2018-07-04 15:30 ` [PATCH 1/3] kvm: remove redundant reserved page check Zhang Yi 2018-07-04 15:30 ` [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Zhang Yi @ 2018-07-04 15:30 ` Zhang Yi 2018-07-04 14:50 ` Dan Williams 2018-07-04 15:25 ` Paolo Bonzini 2 siblings, 2 replies; 11+ messages in thread From: Zhang Yi @ 2018-07-04 15:30 UTC (permalink / raw) To: kvm, linux-kernel, linux-nvdimm, pbonzini, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar 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. Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> --- virt/kvm/kvm_main.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index afb2e6e..1365d18 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, { } +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) +{ + struct page *page = pfn_to_page(pfn); + + return is_zone_device_page(page) && + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); +} + bool kvm_is_reserved_pfn(kvm_pfn_t pfn) { - if (pfn_valid(pfn)) - return PageReserved(pfn_to_page(pfn)); + struct page *page; + + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + return kvm_is_nd_pfn(pfn) ? false : PageReserved(page); + } return true; } -- 2.7.4 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-04 15:30 ` [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem Zhang Yi @ 2018-07-04 14:50 ` Dan Williams 2018-07-04 15:27 ` Paolo Bonzini 2018-07-04 15:25 ` Paolo Bonzini 1 sibling, 1 reply; 11+ messages in thread From: Dan Williams @ 2018-07-04 14:50 UTC (permalink / raw) To: Zhang Yi Cc: Jan Kara, Zhang, Yu C, KVM list, linux-nvdimm, rkrcmar, Linux Kernel Mailing List, Linux MM, Jérôme Glisse, Paolo Bonzini, Christoph Hellwig [ adding Jerome ] On Wed, Jul 4, 2018 at 8:30 AM, Zhang Yi <yi.z.zhang@linux.intel.com> 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. > > Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> > Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> > --- > virt/kvm/kvm_main.c | 17 +++++++++++++++-- > 1 file changed, 15 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index afb2e6e..1365d18 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, > { > } > > +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) > +{ > + struct page *page = pfn_to_page(pfn); > + > + return is_zone_device_page(page) && > + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || > + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); Jerome, might there be any use case to pass MEMORY_DEVICE_PUBLIC memory to a guest vm? > +} > + > bool kvm_is_reserved_pfn(kvm_pfn_t pfn) > { > - if (pfn_valid(pfn)) > - return PageReserved(pfn_to_page(pfn)); > + struct page *page; > + > + if (pfn_valid(pfn)) { > + page = pfn_to_page(pfn); > + return kvm_is_nd_pfn(pfn) ? false : PageReserved(page); > + } > > return true; > } > -- > 2.7.4 > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-04 14:50 ` Dan Williams @ 2018-07-04 15:27 ` Paolo Bonzini 0 siblings, 0 replies; 11+ messages in thread From: Paolo Bonzini @ 2018-07-04 15:27 UTC (permalink / raw) To: Dan Williams, Zhang Yi; +Cc: Jan Kara, KVM list On 04/07/2018 16:50, Dan Williams wrote: >> + return is_zone_device_page(page) && >> + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || >> + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); > Jerome, might there be any use case to pass MEMORY_DEVICE_PUBLIC > memory to a guest vm? > An even better reason to place this in mm.h. :) There should be an function to tell you if a reserved page has accessed/dirty bits etc., that's all that KVM needs to know. Paolo _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-04 15:30 ` [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem Zhang Yi 2018-07-04 14:50 ` Dan Williams @ 2018-07-04 15:25 ` Paolo Bonzini 2018-07-05 13:19 ` Zhang,Yi 1 sibling, 1 reply; 11+ messages in thread From: Paolo Bonzini @ 2018-07-04 15:25 UTC (permalink / raw) To: Zhang Yi, kvm, linux-kernel, linux-nvdimm, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar On 04/07/2018 17:30, 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. > > Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> > Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> > --- > virt/kvm/kvm_main.c | 17 +++++++++++++++-- > 1 file changed, 15 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index afb2e6e..1365d18 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, > { > } > > +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) > +{ > + struct page *page = pfn_to_page(pfn); > + > + return is_zone_device_page(page) && > + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || > + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); > +} If the mm people agree, I'd prefer something that takes a struct page * and is exported by include/linux/mm.h. Then KVM can just do something like struct page *page; if (!pfn_valid(pfn)) return true; page = pfn_to_page(pfn); return PageReserved(page) && !is_dax_page(page); Thanks, Paolo _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-04 15:25 ` Paolo Bonzini @ 2018-07-05 13:19 ` Zhang,Yi 2018-07-09 12:36 ` Jan Kara 0 siblings, 1 reply; 11+ messages in thread From: Zhang,Yi @ 2018-07-05 13:19 UTC (permalink / raw) To: Paolo Bonzini, kvm, linux-kernel, linux-nvdimm, dan.j.williams, jack, hch, yu.c.zhang Cc: linux-mm, yi.z.zhang, rkrcmar On 2018年07月04日 23:25, Paolo Bonzini wrote: > On 04/07/2018 17:30, 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. >> >> Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> >> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> >> --- >> virt/kvm/kvm_main.c | 17 +++++++++++++++-- >> 1 file changed, 15 insertions(+), 2 deletions(-) >> >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index afb2e6e..1365d18 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, >> { >> } >> >> +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) >> +{ >> + struct page *page = pfn_to_page(pfn); >> + >> + return is_zone_device_page(page) && >> + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || >> + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); >> +} > If the mm people agree, I'd prefer something that takes a struct page * > and is exported by include/linux/mm.h. Then KVM can just do something like > > struct page *page; > if (!pfn_valid(pfn)) > return true; > > page = pfn_to_page(pfn); > return PageReserved(page) && !is_dax_page(page); > > Thanks, > > Paolo Yeah, that could be much better. Thanks for your comments Paolo. Hi Kara, Do u have Any opinions/ideas to add such definition in mm? Regards, Yi _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem. 2018-07-05 13:19 ` Zhang,Yi @ 2018-07-09 12:36 ` Jan Kara 0 siblings, 0 replies; 11+ messages in thread From: Jan Kara @ 2018-07-09 12:36 UTC (permalink / raw) To: Zhang,Yi Cc: jack, yu.c.zhang, kvm, linux-nvdimm, rkrcmar, linux-kernel, linux-mm, Paolo Bonzini, hch, yi.z.zhang On Thu 05-07-18 21:19:30, Zhang,Yi wrote: > > > On 2018年07月04日 23:25, Paolo Bonzini wrote: > > On 04/07/2018 17:30, 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. > >> > >> Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com> > >> Signed-off-by: Zhang Yu <yu.c.zhang@linux.intel.com> > >> --- > >> virt/kvm/kvm_main.c | 17 +++++++++++++++-- > >> 1 file changed, 15 insertions(+), 2 deletions(-) > >> > >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > >> index afb2e6e..1365d18 100644 > >> --- a/virt/kvm/kvm_main.c > >> +++ b/virt/kvm/kvm_main.c > >> @@ -140,10 +140,23 @@ __weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm, > >> { > >> } > >> > >> +static bool kvm_is_nd_pfn(kvm_pfn_t pfn) > >> +{ > >> + struct page *page = pfn_to_page(pfn); > >> + > >> + return is_zone_device_page(page) && > >> + ((page->pgmap->type == MEMORY_DEVICE_FS_DAX) || > >> + (page->pgmap->type == MEMORY_DEVICE_DEV_DAX)); > >> +} > > If the mm people agree, I'd prefer something that takes a struct page * > > and is exported by include/linux/mm.h. Then KVM can just do something like > > > > struct page *page; > > if (!pfn_valid(pfn)) > > return true; > > > > page = pfn_to_page(pfn); > > return PageReserved(page) && !is_dax_page(page); > > > > Thanks, > > > > Paolo > Yeah, that could be much better. Thanks for your comments Paolo. > > Hi Kara, Do u have Any opinions/ideas to add such definition in mm? What Paolo suggests sounds good to me. Honza -- Jan Kara <jack@suse.com> SUSE Labs, CR _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2018-07-09 12:36 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-07-04 15:30 [PATCH 0/3] Fix kvm misconceives NVDIMM pages as reserved mmio Zhang Yi 2018-07-04 15:30 ` [PATCH 1/3] kvm: remove redundant reserved page check Zhang Yi 2018-07-04 15:30 ` [PATCH 2/3] mm: introduce memory type MEMORY_DEVICE_DEV_DAX Zhang Yi 2018-07-04 14:50 ` Dan Williams 2018-07-05 13:20 ` zhangyi6 2018-07-04 15:30 ` [PATCH 3/3] kvm: add a function to check if page is from NVDIMM pmem Zhang Yi 2018-07-04 14:50 ` Dan Williams 2018-07-04 15:27 ` Paolo Bonzini 2018-07-04 15:25 ` Paolo Bonzini 2018-07-05 13:19 ` Zhang,Yi 2018-07-09 12:36 ` Jan Kara
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