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Message-Id: <20210804043231.2655537-18-ira.weiny@intel.com>
Date: Tue, 3 Aug 2021 21:32:30 -0700
From: ira.weiny@...el.com
To: Dave Hansen <dave.hansen@...ux.intel.com>,
Dan Williams <dan.j.williams@...el.com>
Cc: Ira Weiny <ira.weiny@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Peter Zijlstra <peterz@...radead.org>,
Andy Lutomirski <luto@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>, x86@...nel.org,
linux-kernel@...r.kernel.org, nvdimm@...ts.linux.dev,
linux-mm@...ck.org
Subject: [PATCH V7 17/18] nvdimm/pmem: Enable stray access protection
From: Ira Weiny <ira.weiny@...el.com>
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 <ira.weiny@...el.com>
---
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
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