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nvdimm/region: Move cache management to the region driver

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Now that cpu_cache_invalidate_memregion() is generically available, use
it to centralize CPU cache management in the nvdimm region driver.

This trades off removing redundant per-dimm CPU cache flushing with an
opportunistic flush on every region disable event to cover the case of
sensitive dirty data in the cache being written back to media after a
secure erase / overwrite event.

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166993221550.1995348.16843505129579060258.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2022-12-01 14:03:35 -08:00
parent 07cb5f705b
commit dc370b28c8
5 changed files with 71 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/acpi/nfit/intel.c
View File

@ -212,9 +212,6 @@ static int __maybe_unused intel_security_unlock(struct nvdimm *nvdimm,
if (!test_bit(NVDIMM_INTEL_UNLOCK_UNIT, &nfit_mem->dsm_mask))
return -ENOTTY;
if (!cpu_cache_has_invalidate_memregion())
return -EINVAL;
memcpy(nd_cmd.cmd.passphrase, key_data->data,
sizeof(nd_cmd.cmd.passphrase));
rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
@ -229,9 +226,6 @@ static int __maybe_unused intel_security_unlock(struct nvdimm *nvdimm,
return -EIO;
}
/* DIMM unlocked, invalidate all CPU caches before we read it */
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
return 0;
}
@ -299,11 +293,6 @@ static int __maybe_unused intel_security_erase(struct nvdimm *nvdimm,
if (!test_bit(cmd, &nfit_mem->dsm_mask))
return -ENOTTY;
if (!cpu_cache_has_invalidate_memregion())
return -EINVAL;
/* flush all cache before we erase DIMM */
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
memcpy(nd_cmd.cmd.passphrase, key->data,
sizeof(nd_cmd.cmd.passphrase));
rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
@ -322,8 +311,6 @@ static int __maybe_unused intel_security_erase(struct nvdimm *nvdimm,
return -ENXIO;
}
/* DIMM erased, invalidate all CPU caches before we read it */
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
return 0;
}
@ -346,9 +333,6 @@ static int __maybe_unused intel_security_query_overwrite(struct nvdimm *nvdimm)
if (!test_bit(NVDIMM_INTEL_QUERY_OVERWRITE, &nfit_mem->dsm_mask))
return -ENOTTY;
if (!cpu_cache_has_invalidate_memregion())
return -EINVAL;
rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
if (rc < 0)
return rc;
@ -362,8 +346,6 @@ static int __maybe_unused intel_security_query_overwrite(struct nvdimm *nvdimm)
return -ENXIO;
}
/* flush all cache before we make the nvdimms available */
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
return 0;
}
@ -388,11 +370,6 @@ static int __maybe_unused intel_security_overwrite(struct nvdimm *nvdimm,
if (!test_bit(NVDIMM_INTEL_OVERWRITE, &nfit_mem->dsm_mask))
return -ENOTTY;
if (!cpu_cache_has_invalidate_memregion())
return -EINVAL;
/* flush all cache before we erase DIMM */
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
memcpy(nd_cmd.cmd.passphrase, nkey->data,
sizeof(nd_cmd.cmd.passphrase));
rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
@ -770,5 +747,3 @@ static const struct nvdimm_fw_ops __intel_fw_ops = {
};
const struct nvdimm_fw_ops *intel_fw_ops = &__intel_fw_ops;
MODULE_IMPORT_NS(DEVMEM);

11
drivers/nvdimm/region.c
View File

@ -2,6 +2,7 @@
/*
* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
*/
#include <linux/memregion.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/device.h>
@ -100,6 +101,16 @@ static void nd_region_remove(struct device *dev)
*/
sysfs_put(nd_region->bb_state);
nd_region->bb_state = NULL;
/*
* Try to flush caches here since a disabled region may be subject to
* secure erase while disabled, and previous dirty data should not be
* written back to a new instance of the region. This only matters on
* bare metal where security commands are available, so silent failure
* here is ok.
*/
if (cpu_cache_has_invalidate_memregion())
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
}
static int child_notify(struct device *dev, void *data)

50
drivers/nvdimm/region_devs.c
View File

@ -59,9 +59,51 @@ static int nvdimm_map_flush(struct device *dev, struct nvdimm *nvdimm, int dimm,
return 0;
}
static int nd_region_invalidate_memregion(struct nd_region *nd_region)
{
int i, incoherent = 0;
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm *nvdimm = nd_mapping->nvdimm;
if (test_bit(NDD_INCOHERENT, &nvdimm->flags)) {
incoherent++;
break;
}
}
if (!incoherent)
return 0;
if (!cpu_cache_has_invalidate_memregion()) {
if (IS_ENABLED(CONFIG_NVDIMM_SECURITY_TEST)) {
dev_warn(
&nd_region->dev,
"Bypassing cpu_cache_invalidate_memergion() for testing!\n");
goto out;
} else {
dev_err(&nd_region->dev,
"Failed to synchronize CPU cache state\n");
return -ENXIO;
}
}
cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
out:
for (i = 0; i < nd_region->ndr_mappings; i++) {
struct nd_mapping *nd_mapping = &nd_region->mapping[i];
struct nvdimm *nvdimm = nd_mapping->nvdimm;
clear_bit(NDD_INCOHERENT, &nvdimm->flags);
}
return 0;
}
int nd_region_activate(struct nd_region *nd_region)
{
int i, j, num_flush = 0;
int i, j, rc, num_flush = 0;
struct nd_region_data *ndrd;
struct device *dev = &nd_region->dev;
size_t flush_data_size = sizeof(void *);
@ -85,6 +127,10 @@ int nd_region_activate(struct nd_region *nd_region)
}
nvdimm_bus_unlock(&nd_region->dev);
rc = nd_region_invalidate_memregion(nd_region);
if (rc)
return rc;
ndrd = devm_kzalloc(dev, sizeof(*ndrd) + flush_data_size, GFP_KERNEL);
if (!ndrd)
return -ENOMEM;
@ -1222,3 +1268,5 @@ int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
return device_for_each_child(&nvdimm_bus->dev, &ctx, region_conflict);
}
MODULE_IMPORT_NS(DEVMEM);

6
drivers/nvdimm/security.c
View File

@ -208,6 +208,8 @@ static int __nvdimm_security_unlock(struct nvdimm *nvdimm)
rc = nvdimm->sec.ops->unlock(nvdimm, data);
dev_dbg(dev, "key: %d unlock: %s\n", key_serial(key),
rc == 0 ? "success" : "fail");
if (rc == 0)
set_bit(NDD_INCOHERENT, &nvdimm->flags);
nvdimm_put_key(key);
nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
@ -374,6 +376,8 @@ static int security_erase(struct nvdimm *nvdimm, unsigned int keyid,
return -ENOKEY;
rc = nvdimm->sec.ops->erase(nvdimm, data, pass_type);
if (rc == 0)
set_bit(NDD_INCOHERENT, &nvdimm->flags);
dev_dbg(dev, "key: %d erase%s: %s\n", key_serial(key),
pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
rc == 0 ? "success" : "fail");
@ -408,6 +412,8 @@ static int security_overwrite(struct nvdimm *nvdimm, unsigned int keyid)
return -ENOKEY;
rc = nvdimm->sec.ops->overwrite(nvdimm, data);
if (rc == 0)
set_bit(NDD_INCOHERENT, &nvdimm->flags);
dev_dbg(dev, "key: %d overwrite submission: %s\n", key_serial(key),
rc == 0 ? "success" : "fail");

5
include/linux/libnvdimm.h
View File

@ -35,6 +35,11 @@ enum {
NDD_WORK_PENDING = 4,
/* dimm supports namespace labels */
NDD_LABELING = 6,
/*
* dimm contents have changed requiring invalidation of CPU caches prior
* to activation of a region that includes this device
*/
NDD_INCOHERENT = 7,
/* need to set a limit somewhere, but yes, this is likely overkill */
ND_IOCTL_MAX_BUFLEN = SZ_4M,