Re: [PATCH v6 18/18] MAINTAINERS: add proc sysctl KUnit test to PROC SYSCTL section
On Wed, Jul 03, 2019 at 05:36:15PM -0700, Brendan Higgins wrote: > Add entry for the new proc sysctl KUnit test to the PROC SYSCTL section. > > Signed-off-by: Brendan Higgins > Reviewed-by: Greg Kroah-Hartman > Reviewed-by: Logan Gunthorpe > Acked-by: Luis Chamberlain Come to think of it, I'd welcome Iurii to be added as a maintainer, with the hope Iurii would be up to review only the kunit changes. Of course if Iurii would be up to also help review future proc changes, even better. 3 pair of eyeballs is better than 2 pairs. Luis ___ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
Re: [PATCH v6 17/18] kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
On Wed, Jul 03, 2019 at 05:36:14PM -0700, Brendan Higgins wrote: > From: Iurii Zaikin > > KUnit tests for initialized data behavior of proc_dointvec that is > explicitly checked in the code. Includes basic parsing tests including > int min/max overflow. > > Signed-off-by: Iurii Zaikin > Signed-off-by: Brendan Higgins > Reviewed-by: Greg Kroah-Hartman > Reviewed-by: Logan Gunthorpe Acked-by: Luis Chamberlain Luis ___ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
Re: [PATCH v6 02/18] kunit: test: add test resource management API
On Wed, Jul 03, 2019 at 05:35:59PM -0700, Brendan Higgins wrote:
> diff --git a/kunit/test.c b/kunit/test.c
> index c030ba5a43e40..a70fbe449e922 100644
> --- a/kunit/test.c
> +++ b/kunit/test.c
> @@ -122,7 +122,8 @@ static void kunit_print_test_case_ok_not_ok(struct
> kunit_case *test_case,
>
> void kunit_init_test(struct kunit *test, const char *name)
> {
> - spin_lock_init(>lock);
Once you re-spin, this above line should be removed.
> + mutex_init(>lock);
> + INIT_LIST_HEAD(>resources);
> test->name = name;
> test->success = true;
> }
Luis
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Re: [PATCH v6 01/18] kunit: test: add KUnit test runner core
On Wed, Jul 03, 2019 at 05:35:58PM -0700, Brendan Higgins wrote:
> +struct kunit {
> + void *priv;
> +
> + /* private: internal use only. */
> + const char *name; /* Read only after initialization! */
> + bool success; /* Read only after test_case finishes! */
> +};
No lock attribute above.
> +void kunit_init_test(struct kunit *test, const char *name)
> +{
> + spin_lock_init(>lock);
> + test->name = name;
> + test->success = true;
> +}
And yet here you initialize a spin lock... This won't compile. Seems
you forgot to remove this line. So I guess a re-spin is better.
Luis
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Re: [PATCH] dax: Fix missed PMD wakeups
On Thu, Jul 04, 2019 at 04:27:14PM -0700, Dan Williams wrote: > On Thu, Jul 4, 2019 at 12:14 PM Matthew Wilcox wrote: > > > > On Thu, Jul 04, 2019 at 06:54:50PM +0200, Jan Kara wrote: > > > On Wed 03-07-19 20:27:28, Matthew Wilcox wrote: > > > > So I think we're good for all current users. > > > > > > Agreed but it is an ugly trap. As I already said, I'd rather pay the > > > unnecessary cost of waiting for pte entry and have an easy to understand > > > interface. If we ever have a real world use case that would care for this > > > optimization, we will need to refactor functions to make this possible and > > > still keep the interfaces sane. For example get_unlocked_entry() could > > > return special "error code" indicating that there's no entry with matching > > > order in xarray but there's a conflict with it. That would be much less > > > error-prone interface. > > > > This is an internal interface. I think it's already a pretty gnarly > > interface to use by definition -- it's going to sleep and might return > > almost anything. There's not much scope for returning an error indicator > > either; value entries occupy half of the range (all odd numbers between 1 > > and ULONG_MAX inclusive), plus NULL. We could use an internal entry, but > > I don't think that makes the interface any easier to use than returning > > a locked entry. > > > > I think this iteration of the patch makes it a little clearer. What do you > > think? > > > > Not much clearer to me. get_unlocked_entry() is now misnamed and this misnamed? You'd rather it was called "try_get_unlocked_entry()"? > arrangement allows for mismatches of @order argument vs @xas > configuration. > Can you describe, or even better demonstrate with > numbers, why it's better to carry this complication than just > converging the waitqueues between the types? You've got the reproducer ;-) It seems quite wrong to make a page fault stall just because another task is working on a different page in the same 2MB chunk. ___ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
[PATCH v15 7/7] xfs: disable map_sync for async flush
Dont support 'MAP_SYNC' with non-DAX files and DAX files
with asynchronous dax_device. Virtio pmem provides
asynchronous host page cache flush mechanism. We don't
support 'MAP_SYNC' with virtio pmem and xfs.
Signed-off-by: Pankaj Gupta
Reviewed-by: Darrick J. Wong
---
fs/xfs/xfs_file.c | 9 ++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index a7ceae90110e..f17652cca5ff 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1203,11 +1203,14 @@ xfs_file_mmap(
struct file *filp,
struct vm_area_struct *vma)
{
+ struct dax_device *dax_dev;
+
+ dax_dev = xfs_find_daxdev_for_inode(file_inode(filp));
/*
-* We don't support synchronous mappings for non-DAX files. At least
-* until someone comes with a sensible use case.
+* We don't support synchronous mappings for non-DAX files and
+* for DAX files if underneath dax_device is not synchronous.
*/
- if (!IS_DAX(file_inode(filp)) && (vma->vm_flags & VM_SYNC))
+ if (!daxdev_mapping_supported(vma, dax_dev))
return -EOPNOTSUPP;
file_accessed(filp);
--
2.20.1
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[PATCH v15 6/7] ext4: disable map_sync for async flush
Dont support 'MAP_SYNC' with non-DAX files and DAX files
with asynchronous dax_device. Virtio pmem provides
asynchronous host page cache flush mechanism. We don't
support 'MAP_SYNC' with virtio pmem and ext4.
Signed-off-by: Pankaj Gupta
Reviewed-by: Jan Kara
---
fs/ext4/file.c | 10 ++
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 98ec11f69cd4..dee549339e13 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -360,15 +360,17 @@ static const struct vm_operations_struct ext4_file_vm_ops
= {
static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *inode = file->f_mapping->host;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct dax_device *dax_dev = sbi->s_daxdev;
- if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb
+ if (unlikely(ext4_forced_shutdown(sbi)))
return -EIO;
/*
-* We don't support synchronous mappings for non-DAX files. At least
-* until someone comes with a sensible use case.
+* We don't support synchronous mappings for non-DAX files and
+* for DAX files if underneath dax_device is not synchronous.
*/
- if (!IS_DAX(file_inode(file)) && (vma->vm_flags & VM_SYNC))
+ if (!daxdev_mapping_supported(vma, dax_dev))
return -EOPNOTSUPP;
file_accessed(file);
--
2.20.1
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[PATCH v15 5/7] dax: check synchronous mapping is supported
This patch introduces 'daxdev_mapping_supported' helper
which checks if 'MAP_SYNC' is supported with filesystem
mapping. It also checks if corresponding dax_device is
synchronous. Virtio pmem device is asynchronous and
does not not support VM_SYNC.
Suggested-by: Jan Kara
Signed-off-by: Pankaj Gupta
Reviewed-by: Jan Kara
---
include/linux/dax.h | 17 +
1 file changed, 17 insertions(+)
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 86fc55c99b58..d1bea3979b5a 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -53,6 +53,18 @@ static inline void set_dax_synchronous(struct dax_device
*dax_dev)
{
__set_dax_synchronous(dax_dev);
}
+/*
+ * Check if given mapping is supported by the file / underlying device.
+ */
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+struct dax_device *dax_dev)
+{
+ if (!(vma->vm_flags & VM_SYNC))
+ return true;
+ if (!IS_DAX(file_inode(vma->vm_file)))
+ return false;
+ return dax_synchronous(dax_dev);
+}
#else
static inline struct dax_device *dax_get_by_host(const char *host)
{
@@ -87,6 +99,11 @@ static inline bool dax_synchronous(struct dax_device
*dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
+static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
+ struct dax_device *dax_dev)
+{
+ return !(vma->vm_flags & VM_SYNC);
+}
#endif
struct writeback_control;
--
2.20.1
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[PATCH v15 4/7] dm: enable synchronous dax
This patch sets dax device 'DAXDEV_SYNC' flag if all the target
devices of device mapper support synchrononous DAX. If device
mapper consists of both synchronous and asynchronous dax devices,
we don't set 'DAXDEV_SYNC' flag.
'dm_table_supports_dax' is refactored to pass 'iterate_devices_fn'
as argument so that the callers can pass the appropriate functions.
Suggested-by: Mike Snitzer
Signed-off-by: Pankaj Gupta
Reviewed-by: Mike Snitzer
---
drivers/md/dm-table.c | 24 ++--
drivers/md/dm.c | 2 +-
drivers/md/dm.h | 5 -
3 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 350cf0451456..81c55304c4fa 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -881,7 +881,7 @@ void dm_table_set_type(struct dm_table *t, enum
dm_queue_mode type)
EXPORT_SYMBOL_GPL(dm_table_set_type);
/* validate the dax capability of the target device span */
-static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
+int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
int blocksize = *(int *) data;
@@ -890,7 +890,15 @@ static int device_supports_dax(struct dm_target *ti,
struct dm_dev *dev,
start, len);
}
-bool dm_table_supports_dax(struct dm_table *t, int blocksize)
+/* Check devices support synchronous DAX */
+static int device_synchronous(struct dm_target *ti, struct dm_dev *dev,
+ sector_t start, sector_t len, void *data)
+{
+ return dax_synchronous(dev->dax_dev);
+}
+
+bool dm_table_supports_dax(struct dm_table *t,
+ iterate_devices_callout_fn iterate_fn, int *blocksize)
{
struct dm_target *ti;
unsigned i;
@@ -903,8 +911,7 @@ bool dm_table_supports_dax(struct dm_table *t, int
blocksize)
return false;
if (!ti->type->iterate_devices ||
- !ti->type->iterate_devices(ti, device_supports_dax,
- ))
+ !ti->type->iterate_devices(ti, iterate_fn, blocksize))
return false;
}
@@ -940,6 +947,7 @@ static int dm_table_determine_type(struct dm_table *t)
struct dm_target *tgt;
struct list_head *devices = dm_table_get_devices(t);
enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
+ int page_size = PAGE_SIZE;
if (t->type != DM_TYPE_NONE) {
/* target already set the table's type */
@@ -984,7 +992,7 @@ static int dm_table_determine_type(struct dm_table *t)
verify_bio_based:
/* We must use this table as bio-based */
t->type = DM_TYPE_BIO_BASED;
- if (dm_table_supports_dax(t, PAGE_SIZE) ||
+ if (dm_table_supports_dax(t, device_supports_dax, _size) ||
(list_empty(devices) && live_md_type ==
DM_TYPE_DAX_BIO_BASED)) {
t->type = DM_TYPE_DAX_BIO_BASED;
} else {
@@ -1883,6 +1891,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct
request_queue *q,
struct queue_limits *limits)
{
bool wc = false, fua = false;
+ int page_size = PAGE_SIZE;
/*
* Copy table's limits to the DM device's request_queue
@@ -1910,8 +1919,11 @@ void dm_table_set_restrictions(struct dm_table *t,
struct request_queue *q,
}
blk_queue_write_cache(q, wc, fua);
- if (dm_table_supports_dax(t, PAGE_SIZE))
+ if (dm_table_supports_dax(t, device_supports_dax, _size)) {
blk_queue_flag_set(QUEUE_FLAG_DAX, q);
+ if (dm_table_supports_dax(t, device_synchronous, NULL))
+ set_dax_synchronous(t->md->dax_dev);
+ }
else
blk_queue_flag_clear(QUEUE_FLAG_DAX, q);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b1caa7188209..b92c42a72ad4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1119,7 +1119,7 @@ static bool dm_dax_supported(struct dax_device *dax_dev,
struct block_device *bd
if (!map)
return false;
- ret = dm_table_supports_dax(map, blocksize);
+ ret = dm_table_supports_dax(map, device_supports_dax, );
dm_put_live_table(md, srcu_idx);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 17e3db54404c..0475673337f3 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -72,7 +72,10 @@ bool dm_table_bio_based(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
-bool dm_table_supports_dax(struct dm_table *t, int blocksize);
+bool dm_table_supports_dax(struct dm_table *t, iterate_devices_callout_fn fn,
+ int *blocksize);
+int
[PATCH v15 3/7] libnvdimm: add dax_dev sync flag
This patch adds 'DAXDEV_SYNC' flag which is set
for nd_region doing synchronous flush. This later
is used to disable MAP_SYNC functionality for
ext4 & xfs filesystem for devices don't support
synchronous flush.
Signed-off-by: Pankaj Gupta
---
drivers/dax/bus.c| 2 +-
drivers/dax/super.c | 19 ++-
drivers/md/dm.c | 3 ++-
drivers/nvdimm/pmem.c| 5 -
drivers/nvdimm/region_devs.c | 7 +++
drivers/s390/block/dcssblk.c | 2 +-
include/linux/dax.h | 24 ++--
include/linux/libnvdimm.h| 1 +
8 files changed, 56 insertions(+), 7 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 2109cfe80219..5f184e751c82 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -388,7 +388,7 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region
*dax_region, int id,
* No 'host' or dax_operations since there is no access to this
* device outside of mmap of the resulting character device.
*/
- dax_dev = alloc_dax(dev_dax, NULL, NULL);
+ dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
if (!dax_dev)
goto err;
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 4e5ae7e8b557..8ab12068eea3 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -195,6 +195,8 @@ enum dax_device_flags {
DAXDEV_ALIVE,
/* gate whether dax_flush() calls the low level flush routine */
DAXDEV_WRITE_CACHE,
+ /* flag to check if device supports synchronous flush */
+ DAXDEV_SYNC,
};
/**
@@ -372,6 +374,18 @@ bool dax_write_cache_enabled(struct dax_device *dax_dev)
}
EXPORT_SYMBOL_GPL(dax_write_cache_enabled);
+bool __dax_synchronous(struct dax_device *dax_dev)
+{
+ return test_bit(DAXDEV_SYNC, _dev->flags);
+}
+EXPORT_SYMBOL_GPL(__dax_synchronous);
+
+void __set_dax_synchronous(struct dax_device *dax_dev)
+{
+ set_bit(DAXDEV_SYNC, _dev->flags);
+}
+EXPORT_SYMBOL_GPL(__set_dax_synchronous);
+
bool dax_alive(struct dax_device *dax_dev)
{
lockdep_assert_held(_srcu);
@@ -526,7 +540,7 @@ static void dax_add_host(struct dax_device *dax_dev, const
char *host)
}
struct dax_device *alloc_dax(void *private, const char *__host,
- const struct dax_operations *ops)
+ const struct dax_operations *ops, unsigned long flags)
{
struct dax_device *dax_dev;
const char *host;
@@ -549,6 +563,9 @@ struct dax_device *alloc_dax(void *private, const char
*__host,
dax_add_host(dax_dev, host);
dax_dev->ops = ops;
dax_dev->private = private;
+ if (flags & DAXDEV_F_SYNC)
+ set_dax_synchronous(dax_dev);
+
return dax_dev;
err_dev:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 5475081dcbd6..b1caa7188209 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1991,7 +1991,8 @@ static struct mapped_device *alloc_dev(int minor)
sprintf(md->disk->disk_name, "dm-%d", minor);
if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
- md->dax_dev = alloc_dax(md, md->disk->disk_name, _dax_ops);
+ md->dax_dev = alloc_dax(md, md->disk->disk_name,
+ _dax_ops, 0);
if (!md->dax_dev)
goto bad;
}
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 223da63d1bd7..8be868e2a18b 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -376,6 +376,7 @@ static int pmem_attach_disk(struct device *dev,
struct gendisk *disk;
void *addr;
int rc;
+ unsigned long flags = 0UL;
pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
if (!pmem)
@@ -474,7 +475,9 @@ static int pmem_attach_disk(struct device *dev,
nvdimm_badblocks_populate(nd_region, >bb, _res);
disk->bb = >bb;
- dax_dev = alloc_dax(pmem, disk->disk_name, _dax_ops);
+ if (is_nvdimm_sync(nd_region))
+ flags = DAXDEV_F_SYNC;
+ dax_dev = alloc_dax(pmem, disk->disk_name, _dax_ops, flags);
if (!dax_dev) {
put_disk(disk);
return -ENOMEM;
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index eca2e62af134..56f2227f192a 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1211,6 +1211,13 @@ int nvdimm_has_cache(struct nd_region *nd_region)
}
EXPORT_SYMBOL_GPL(nvdimm_has_cache);
+bool is_nvdimm_sync(struct nd_region *nd_region)
+{
+ return is_nd_pmem(_region->dev) &&
+ !test_bit(ND_REGION_ASYNC, _region->flags);
+}
+EXPORT_SYMBOL_GPL(is_nvdimm_sync);
+
struct conflict_context {
struct nd_region *nd_region;
resource_size_t start, size;
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index d04d4378ca50..63502ca537eb 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@
[PATCH v15 2/7] virtio-pmem: Add virtio pmem driver
This patch adds virtio-pmem driver for KVM guest.
Guest reads the persistent memory range information from
Qemu over VIRTIO and registers it on nvdimm_bus. It also
creates a nd_region object with the persistent memory
range information so that existing 'nvdimm/pmem' driver
can reserve this into system memory map. This way
'virtio-pmem' driver uses existing functionality of pmem
driver to register persistent memory compatible for DAX
capable filesystems.
This also provides function to perform guest flush over
VIRTIO from 'pmem' driver when userspace performs flush
on DAX memory range.
Signed-off-by: Pankaj Gupta
Reviewed-by: Yuval Shaia
Acked-by: Michael S. Tsirkin
Acked-by: Jakub Staron
Tested-by: Jakub Staron
Reviewed-by: Cornelia Huck
---
drivers/nvdimm/Makefile | 1 +
drivers/nvdimm/nd_virtio.c | 125 +++
drivers/nvdimm/virtio_pmem.c | 122 ++
drivers/nvdimm/virtio_pmem.h | 55 ++
drivers/virtio/Kconfig | 11 +++
include/uapi/linux/virtio_ids.h | 1 +
include/uapi/linux/virtio_pmem.h | 34 +
7 files changed, 349 insertions(+)
create mode 100644 drivers/nvdimm/nd_virtio.c
create mode 100644 drivers/nvdimm/virtio_pmem.c
create mode 100644 drivers/nvdimm/virtio_pmem.h
create mode 100644 include/uapi/linux/virtio_pmem.h
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 6f2a088afad6..cefe233e0b52 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ND_BTT) += nd_btt.o
obj-$(CONFIG_ND_BLK) += nd_blk.o
obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
obj-$(CONFIG_OF_PMEM) += of_pmem.o
+obj-$(CONFIG_VIRTIO_PMEM) += virtio_pmem.o nd_virtio.o
nd_pmem-y := pmem.o
diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c
new file mode 100644
index ..8645275c08c2
--- /dev/null
+++ b/drivers/nvdimm/nd_virtio.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * virtio_pmem.c: Virtio pmem Driver
+ *
+ * Discovers persistent memory range information
+ * from host and provides a virtio based flushing
+ * interface.
+ */
+#include "virtio_pmem.h"
+#include "nd.h"
+
+ /* The interrupt handler */
+void virtio_pmem_host_ack(struct virtqueue *vq)
+{
+ struct virtio_pmem *vpmem = vq->vdev->priv;
+ struct virtio_pmem_request *req_data, *req_buf;
+ unsigned long flags;
+ unsigned int len;
+
+ spin_lock_irqsave(>pmem_lock, flags);
+ while ((req_data = virtqueue_get_buf(vq, )) != NULL) {
+ req_data->done = true;
+ wake_up(_data->host_acked);
+
+ if (!list_empty(>req_list)) {
+ req_buf = list_first_entry(>req_list,
+ struct virtio_pmem_request, list);
+ req_buf->wq_buf_avail = true;
+ wake_up(_buf->wq_buf);
+ list_del(_buf->list);
+ }
+ }
+ spin_unlock_irqrestore(>pmem_lock, flags);
+}
+EXPORT_SYMBOL_GPL(virtio_pmem_host_ack);
+
+ /* The request submission function */
+static int virtio_pmem_flush(struct nd_region *nd_region)
+{
+ struct virtio_device *vdev = nd_region->provider_data;
+ struct virtio_pmem *vpmem = vdev->priv;
+ struct virtio_pmem_request *req_data;
+ struct scatterlist *sgs[2], sg, ret;
+ unsigned long flags;
+ int err, err1;
+
+ might_sleep();
+ req_data = kmalloc(sizeof(*req_data), GFP_KERNEL);
+ if (!req_data)
+ return -ENOMEM;
+
+ req_data->done = false;
+ init_waitqueue_head(_data->host_acked);
+ init_waitqueue_head(_data->wq_buf);
+ INIT_LIST_HEAD(_data->list);
+ req_data->req.type = cpu_to_virtio32(vdev, VIRTIO_PMEM_REQ_TYPE_FLUSH);
+ sg_init_one(, _data->req, sizeof(req_data->req));
+ sgs[0] =
+ sg_init_one(, _data->resp.ret, sizeof(req_data->resp));
+ sgs[1] =
+
+ spin_lock_irqsave(>pmem_lock, flags);
+/*
+ * If virtqueue_add_sgs returns -ENOSPC then req_vq virtual
+ * queue does not have free descriptor. We add the request
+ * to req_list and wait for host_ack to wake us up when free
+ * slots are available.
+ */
+ while ((err = virtqueue_add_sgs(vpmem->req_vq, sgs, 1, 1, req_data,
+ GFP_ATOMIC)) == -ENOSPC) {
+
+ dev_info(>dev, "failed to send command to virtio pmem
device, no free slots in the virtqueue\n");
+ req_data->wq_buf_avail = false;
+ list_add_tail(_data->list, >req_list);
+ spin_unlock_irqrestore(>pmem_lock, flags);
+
+ /* A host response results in "host_ack" getting called */
+ wait_event(req_data->wq_buf, req_data->wq_buf_avail);
+ spin_lock_irqsave(>pmem_lock, flags);
+ }
+ err1 =
[PATCH v15 1/7] libnvdimm: nd_region flush callback support
This patch adds functionality to perform flush from guest
to host over VIRTIO. We are registering a callback based
on 'nd_region' type. virtio_pmem driver requires this special
flush function. For rest of the region types we are registering
existing flush function. Report error returned by host fsync
failure to userspace.
Signed-off-by: Pankaj Gupta
---
drivers/acpi/nfit/core.c | 4 ++--
drivers/nvdimm/claim.c | 6 --
drivers/nvdimm/nd.h | 1 +
drivers/nvdimm/pmem.c| 13 -
drivers/nvdimm/region_devs.c | 26 --
include/linux/libnvdimm.h| 9 -
6 files changed, 47 insertions(+), 12 deletions(-)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index f1ed0befe303..9ddd8667153e 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2434,7 +2434,7 @@ static void write_blk_ctl(struct nfit_blk *nfit_blk,
unsigned int bw,
offset = to_interleave_offset(offset, mmio);
writeq(cmd, mmio->addr.base + offset);
- nvdimm_flush(nfit_blk->nd_region);
+ nvdimm_flush(nfit_blk->nd_region, NULL);
if (nfit_blk->dimm_flags & NFIT_BLK_DCR_LATCH)
readq(mmio->addr.base + offset);
@@ -2483,7 +2483,7 @@ static int acpi_nfit_blk_single_io(struct nfit_blk
*nfit_blk,
}
if (rw)
- nvdimm_flush(nfit_blk->nd_region);
+ nvdimm_flush(nfit_blk->nd_region, NULL);
rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
return rc;
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index fb667bf469c7..13510bae1e6f 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -263,7 +263,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
struct nd_namespace_io *nsio = to_nd_namespace_io(>dev);
unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
sector_t sector = offset >> 9;
- int rc = 0;
+ int rc = 0, ret = 0;
if (unlikely(!size))
return 0;
@@ -301,7 +301,9 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
}
memcpy_flushcache(nsio->addr + offset, buf, size);
- nvdimm_flush(to_nd_region(ndns->dev.parent));
+ ret = nvdimm_flush(to_nd_region(ndns->dev.parent), NULL);
+ if (ret)
+ rc = ret;
return rc;
}
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index a5ac3b240293..0c74d2428bd7 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -159,6 +159,7 @@ struct nd_region {
struct badblocks bb;
struct nd_interleave_set *nd_set;
struct nd_percpu_lane __percpu *lane;
+ int (*flush)(struct nd_region *nd_region, struct bio *bio);
struct nd_mapping mapping[0];
};
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 0279eb1da3ef..c757a47183b8 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -192,6 +192,7 @@ static blk_status_t pmem_do_bvec(struct pmem_device *pmem,
struct page *page,
static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
{
+ int ret = 0;
blk_status_t rc = 0;
bool do_acct;
unsigned long start;
@@ -201,7 +202,7 @@ static blk_qc_t pmem_make_request(struct request_queue *q,
struct bio *bio)
struct nd_region *nd_region = to_region(pmem);
if (bio->bi_opf & REQ_PREFLUSH)
- nvdimm_flush(nd_region);
+ ret = nvdimm_flush(nd_region, bio);
do_acct = nd_iostat_start(bio, );
bio_for_each_segment(bvec, bio, iter) {
@@ -216,7 +217,10 @@ static blk_qc_t pmem_make_request(struct request_queue *q,
struct bio *bio)
nd_iostat_end(bio, start);
if (bio->bi_opf & REQ_FUA)
- nvdimm_flush(nd_region);
+ ret = nvdimm_flush(nd_region, bio);
+
+ if (ret)
+ bio->bi_status = errno_to_blk_status(ret);
bio_endio(bio);
return BLK_QC_T_NONE;
@@ -469,7 +473,6 @@ static int pmem_attach_disk(struct device *dev,
}
dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
pmem->dax_dev = dax_dev;
-
gendev = disk_to_dev(disk);
gendev->groups = pmem_attribute_groups;
@@ -527,14 +530,14 @@ static int nd_pmem_remove(struct device *dev)
sysfs_put(pmem->bb_state);
pmem->bb_state = NULL;
}
- nvdimm_flush(to_nd_region(dev->parent));
+ nvdimm_flush(to_nd_region(dev->parent), NULL);
return 0;
}
static void nd_pmem_shutdown(struct device *dev)
{
- nvdimm_flush(to_nd_region(dev->parent));
+ nvdimm_flush(to_nd_region(dev->parent), NULL);
}
static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index b4ef7d9ff22e..e5b59708865e 100644
--- a/drivers/nvdimm/region_devs.c
+++
[PATCH v15 0/7] virtio pmem driver
Hi Dan, This series has only change in patch 2 for linux-next build failure. There is no functional change. Keeping all the existing review/acks and reposting the patch series for merging via libnvdimm tree. --- This patch series has implementation for "virtio pmem". "virtio pmem" is fake persistent memory(nvdimm) in guest which allows to bypass the guest page cache. This also implements a VIRTIO based asynchronous flush mechanism. Sharing guest kernel driver in this patchset with the changes suggested in v4. Tested with Qemu side device emulation [5] for virtio-pmem. Documented the impact of possible page cache side channel attacks with suggested countermeasures. Details of project idea for 'virtio pmem' flushing interface is shared [3] & [4]. Implementation is divided into two parts: New virtio pmem guest driver and qemu code changes for new virtio pmem paravirtualized device. 1. Guest virtio-pmem kernel driver - - Reads persistent memory range from paravirt device and registers with 'nvdimm_bus'. - 'nvdimm/pmem' driver uses this information to allocate persistent memory region and setup filesystem operations to the allocated memory. - virtio pmem driver implements asynchronous flushing interface to flush from guest to host. 2. Qemu virtio-pmem device - - Creates virtio pmem device and exposes a memory range to KVM guest. - At host side this is file backed memory which acts as persistent memory. - Qemu side flush uses aio thread pool API's and virtio for asynchronous guest multi request handling. Virtio-pmem security implications and countermeasures: - In previous posting of kernel driver, there was discussion [7] on possible implications of page cache side channel attacks with virtio pmem. After thorough analysis of details of known side channel attacks, below are the suggestions: - Depends entirely on how host backing image file is mapped into guest address space. - virtio-pmem device emulation, by default shared mapping is used to map host backing file. It is recommended to use separate backing file at host side for every guest. This will prevent any possibility of executing common code from multiple guests and any chance of inferring guest local data based based on execution time. - If backing file is required to be shared among multiple guests it is recommended to don't support host page cache eviction commands from the guest driver. This will avoid any possibility of inferring guest local data or host data from another guest. - Proposed device specification [6] for virtio-pmem device with details of possible security implications and suggested countermeasures for device emulation. Virtio-pmem errors handling: Checked behaviour of virtio-pmem for below types of errors Need suggestions on expected behaviour for handling these errors? - Hardware Errors: Uncorrectable recoverable Errors: a] virtio-pmem: - As per current logic if error page belongs to Qemu process, host MCE handler isolates(hwpoison) that page and send SIGBUS. Qemu SIGBUS handler injects exception to KVM guest. - KVM guest then isolates the page and send SIGBUS to guest userspace process which has mapped the page. b] Existing implementation for ACPI pmem driver: - Handles such errors with MCE notifier and creates a list of bad blocks. Read/direct access DAX operation return EIO if accessed memory page fall in bad block list. - It also starts backgound scrubbing. - Similar functionality can be reused in virtio-pmem with MCE notifier but without scrubbing(no ACPI/ARS)? Need inputs to confirm if this behaviour is ok or needs any change? Changes from PATCH v13: [1] - Rebase to Linux-5.2-rc7 - Fix Linux-next build failure for undefined type Changes from PATCH v13: [2] - Rebased to Linux-5.2-rc5 - Fix S390x build failure in patch 3 - Fix for !CONFIG_DAX with dax_synchronous - Fix sparse warning in virtio patch 2 Changes from PATCH v12: - Minor changes(function name, dev_err -> dev_info & make function static in virtio patch - [Cornelia] - Added r-o-b of Mike in patch 4 Changes from PATCH v11: - Change implmentation for setting of synchronous DAX type for device mapper - [Mike] Changes from PATCH v10: - Rebased on Linux-5.2-rc4 Changes from PATCH v9: - Kconfig help text add two spaces - Randy - Fixed libnvdimm 'bio' include warning - Dan - virtio-pmem, separate request/resp struct and move to uapi file with updated license - DavidH - Use virtio32* type for req/resp endianess - DavidH - Added tested-by & ack-by of Jakob - Rebased to 5.2-rc1 Changes from PATCH v8: - Set device mapper synchronous if all
