[PATCH V7 17/18] nvdimm/pmem: Enable stray access protection
From: <hidden>
Date: 2021-08-04 04:33:47
Also in:
lkml, nvdimm
Subsystem:
libnvdimm pmem: persistent memory driver, libnvdimm: non-volatile memory device subsystem, the rest · Maintainers:
Dan Williams, Vishal Verma, Dave Jiang, Alison Schofield, Linus Torvalds
From: Ira Weiny <redacted>
Now that all potential / valid kernel initiated access' to PMEM have
been annotated with {__}pgmap_mk_{readwrite,noaccess}(), turn on
PGMAP_PROTECTION.
Implement the dax_protected which communicates this memory has extra
protection. Also implement pmem_mk_{readwrite,noaccess}() to relax
those protections for valid users.
Internally, the pmem driver uses a cached virtual address,
pmem->virt_addr (pmem_addr).
Call __pgmap_mk_{readwrite,noaccess}() directly when PGMAP_PROTECTION is
active on the device.
Signed-off-by: Ira Weiny <redacted>
---
Changes for V7
Remove global param
Add internal structure which uses the pmem device and pgmap
device directly in the *_mk_*() calls.
Add pmem dax ops callbacks
Use pgmap_protection_enabled()
s/PGMAP_PKEY_PROTECT/PGMAP_PROTECTION
---
drivers/nvdimm/pmem.c | 55 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 54 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 1e0615b8565e..6e924b907264 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c@@ -138,6 +138,18 @@ static blk_status_t read_pmem(struct page *page, unsigned int off, return BLK_STS_OK; } +static void __pmem_mk_readwrite(struct pmem_device *pmem) +{ + if (pmem->pgmap.flags & PGMAP_PROTECTION) + __pgmap_mk_readwrite(&pmem->pgmap); +} + +static void __pmem_mk_noaccess(struct pmem_device *pmem) +{ + if (pmem->pgmap.flags & PGMAP_PROTECTION) + __pgmap_mk_noaccess(&pmem->pgmap); +} + static blk_status_t pmem_do_read(struct pmem_device *pmem, struct page *page, unsigned int page_off, sector_t sector, unsigned int len)
@@ -149,7 +161,10 @@ static blk_status_t pmem_do_read(struct pmem_device *pmem, if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) return BLK_STS_IOERR; + __pmem_mk_readwrite(pmem); rc = read_pmem(page, page_off, pmem_addr, len); + __pmem_mk_noaccess(pmem); + flush_dcache_page(page); return rc; }
@@ -181,11 +196,14 @@ static blk_status_t pmem_do_write(struct pmem_device *pmem, * after clear poison. */ flush_dcache_page(page); + + __pmem_mk_readwrite(pmem); write_pmem(pmem_addr, page, page_off, len); if (unlikely(bad_pmem)) { rc = pmem_clear_poison(pmem, pmem_off, len); write_pmem(pmem_addr, page, page_off, len); } + __pmem_mk_noaccess(pmem); return rc; }
@@ -320,6 +338,23 @@ static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, return _copy_mc_to_iter(addr, bytes, i); } +static bool pmem_map_protected(struct dax_device *dax_dev) +{ + struct pmem_device *pmem = dax_get_private(dax_dev); + + return (pmem->pgmap.flags & PGMAP_PROTECTION); +} + +static void pmem_mk_readwrite(struct dax_device *dax_dev) +{ + __pmem_mk_readwrite(dax_get_private(dax_dev)); +} + +static void pmem_mk_noaccess(struct dax_device *dax_dev) +{ + __pmem_mk_noaccess(dax_get_private(dax_dev)); +} + static const struct dax_operations pmem_dax_ops = { .direct_access = pmem_dax_direct_access, .dax_supported = generic_fsdax_supported,
@@ -328,6 +363,17 @@ static const struct dax_operations pmem_dax_ops = { .zero_page_range = pmem_dax_zero_page_range, }; +static const struct dax_operations pmem_protected_dax_ops = { + .direct_access = pmem_dax_direct_access, + .dax_supported = generic_fsdax_supported, + .copy_from_iter = pmem_copy_from_iter, + .copy_to_iter = pmem_copy_to_iter, + .zero_page_range = pmem_dax_zero_page_range, + .map_protected = pmem_map_protected, + .mk_readwrite = pmem_mk_readwrite, + .mk_noaccess = pmem_mk_noaccess, +}; + static const struct attribute_group *pmem_attribute_groups[] = { &dax_attribute_group, NULL,
@@ -432,6 +478,8 @@ static int pmem_attach_disk(struct device *dev, if (is_nd_pfn(dev)) { pmem->pgmap.type = MEMORY_DEVICE_FS_DAX; pmem->pgmap.ops = &fsdax_pagemap_ops; + if (pgmap_protection_enabled()) + pmem->pgmap.flags |= PGMAP_PROTECTION; addr = devm_memremap_pages(dev, &pmem->pgmap); pfn_sb = nd_pfn->pfn_sb; pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
@@ -446,6 +494,8 @@ static int pmem_attach_disk(struct device *dev, pmem->pgmap.nr_range = 1; pmem->pgmap.type = MEMORY_DEVICE_FS_DAX; pmem->pgmap.ops = &fsdax_pagemap_ops; + if (pgmap_protection_enabled()) + pmem->pgmap.flags |= PGMAP_PROTECTION; addr = devm_memremap_pages(dev, &pmem->pgmap); pmem->pfn_flags |= PFN_MAP; bb_range = pmem->pgmap.range;
@@ -483,7 +533,10 @@ static int pmem_attach_disk(struct device *dev, if (is_nvdimm_sync(nd_region)) flags = DAXDEV_F_SYNC; - dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags); + if (pmem->pgmap.flags & PGMAP_PROTECTION) + dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_protected_dax_ops, flags); + else + dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags); if (IS_ERR(dax_dev)) { return PTR_ERR(dax_dev); }
--
2.28.0.rc0.12.gb6a658bd00c9