* [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device
@ 2017-05-26 2:24 Haozhong Zhang
2017-05-26 2:24 ` [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment Haozhong Zhang
2017-05-30 9:15 ` [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Stefan Hajnoczi
0 siblings, 2 replies; 6+ messages in thread
From: Haozhong Zhang @ 2017-05-26 2:24 UTC (permalink / raw)
To: qemu-devel
Cc: Haozhong Zhang, Michael S. Tsirkin, Igor Mammedov,
Xiao Guangrong, Stefan Hajnoczi, Dan Williams
Applications in Linux guest that use device-dax never trigger flush
that can be trapped by KVM/QEMU. Meanwhile, if the host backend is not
device-dax, QEMU cannot guarantee the persistence of guest writes.
Before solving this flushing problem, QEMU should warn users if the
host backend is not device-dax.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-id: CAPcyv4hV2-ZW8SMCRtD0P_86KgR3DHOvNe+6T5SY2u7wXg3gEg@mail.gmail.com
---
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
---
hw/mem/nvdimm.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index db896b0bb6..c7bb407f33 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -26,6 +26,7 @@
#include "qapi/error.h"
#include "qapi/visitor.h"
#include "hw/mem/nvdimm.h"
+#include "qemu/error-report.h"
static void nvdimm_get_label_size(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
@@ -78,12 +79,48 @@ static MemoryRegion *nvdimm_get_memory_region(PCDIMMDevice *dimm)
return &nvdimm->nvdimm_mr;
}
+static void nvdimm_check_dax(HostMemoryBackend *hostmem)
+{
+ char *mem_path =
+ object_property_get_str(OBJECT(hostmem), "mem-path", NULL);
+ char *dev_name = NULL, *sysfs_path = NULL;
+ bool is_dax = false;
+
+ if (!mem_path) {
+ goto out;
+ }
+
+ if (!g_str_has_prefix(mem_path, "/dev/dax")) {
+ goto out;
+ }
+
+ dev_name = mem_path + strlen("/dev/");
+ sysfs_path = g_strdup_printf("/sys/class/dax/%s", dev_name);
+ if (access(sysfs_path, F_OK)) {
+ goto out;
+ }
+
+ is_dax = true;
+
+ out:
+ if (!is_dax) {
+ error_report("warning: nvdimm backend %s is not DAX device, "
+ "unable to guarantee persistence of guest writes",
+ mem_path ?: "RAM");
+ }
+
+ g_free(sysfs_path);
+ g_free(mem_path);
+}
+
static void nvdimm_realize(PCDIMMDevice *dimm, Error **errp)
{
MemoryRegion *mr = host_memory_backend_get_memory(dimm->hostmem, errp);
NVDIMMDevice *nvdimm = NVDIMM(dimm);
uint64_t align, pmem_size, size = memory_region_size(mr);
+ nvdimm_check_dax(dimm->hostmem);
+
align = memory_region_get_alignment(mr);
pmem_size = size - nvdimm->label_size;
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment
2017-05-26 2:24 [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Haozhong Zhang
@ 2017-05-26 2:24 ` Haozhong Zhang
2017-05-30 9:16 ` Stefan Hajnoczi
2017-05-30 9:15 ` [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Stefan Hajnoczi
1 sibling, 1 reply; 6+ messages in thread
From: Haozhong Zhang @ 2017-05-26 2:24 UTC (permalink / raw)
To: qemu-devel
Cc: Haozhong Zhang, Eduardo Habkost, Igor Mammedov, Paolo Bonzini,
Peter Crosthwaite, Richard Henderson, Xiao Guangrong,
Stefan Hajnoczi, Dan Williams
file_ram_alloc() currently maps the backend file via mmap to a virtual
address aligned to the value returned by qemu_fd_getpagesize(). When a
DAX device (e.g. /dev/dax0.0) is used as the backend file, its kernel
mmap implementation may require an alignment larger than what
qemu_fd_get_pagesize() returns (e.g. 2MB vs. 4KB), and mmap may fail.
This commit adds an attribute 'align' to hostmem-file, so that users
can specify a proper alignment that satisfies the kernel requirement.
If 'align' is not specified or is 0, the value returned by
qemu_fd_get_pagesize() will be used as before.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
---
backends/hostmem-file.c | 41 ++++++++++++++++++++++++++++++++++++++++-
exec.c | 8 +++++++-
include/exec/memory.h | 2 ++
memory.c | 2 ++
numa.c | 2 +-
5 files changed, 52 insertions(+), 3 deletions(-)
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c
index fc4ef46d11..d44fb41b55 100644
--- a/backends/hostmem-file.c
+++ b/backends/hostmem-file.c
@@ -33,6 +33,7 @@ struct HostMemoryBackendFile {
bool share;
char *mem_path;
+ uint64_t align;
};
static void
@@ -57,7 +58,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
path = object_get_canonical_path(OBJECT(backend));
memory_region_init_ram_from_file(&backend->mr, OBJECT(backend),
path,
- backend->size, fb->share,
+ backend->size, fb->align, fb->share,
fb->mem_path, errp);
g_free(path);
}
@@ -104,6 +105,40 @@ static void file_memory_backend_set_share(Object *o, bool value, Error **errp)
}
static void
+file_memory_backend_get_align(Object *o, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
+ uint64_t val = fb->align;
+
+ visit_type_size(v, name, &val, errp);
+}
+
+static void
+file_memory_backend_set_align(Object *o, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ HostMemoryBackend *backend = MEMORY_BACKEND(o);
+ HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
+ Error *local_err = NULL;
+ uint64_t val;
+
+ if (host_memory_backend_mr_inited(backend)) {
+ error_setg(&local_err, "cannot change property value");
+ goto out;
+ }
+
+ visit_type_size(v, name, &val, &local_err);
+ if (local_err) {
+ goto out;
+ }
+ fb->align = val;
+
+ out:
+ error_propagate(errp, local_err);
+}
+
+static void
file_backend_class_init(ObjectClass *oc, void *data)
{
HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
@@ -116,6 +151,10 @@ file_backend_class_init(ObjectClass *oc, void *data)
object_class_property_add_str(oc, "mem-path",
get_mem_path, set_mem_path,
&error_abort);
+ object_class_property_add(oc, "align", "int",
+ file_memory_backend_get_align,
+ file_memory_backend_set_align,
+ NULL, NULL, &error_abort);
}
static void file_backend_instance_finalize(Object *o)
diff --git a/exec.c b/exec.c
index ff16f04f2b..5bb62e2e98 100644
--- a/exec.c
+++ b/exec.c
@@ -1549,7 +1549,13 @@ static void *file_ram_alloc(RAMBlock *block,
}
block->page_size = qemu_fd_getpagesize(fd);
- block->mr->align = block->page_size;
+ if (block->mr->align % block->page_size) {
+ error_setg(errp, "alignment 0x%" PRIx64 " must be "
+ "multiple of page size 0x%" PRIx64,
+ block->mr->align, block->page_size);
+ goto error;
+ }
+ block->mr->align = MAX(block->page_size, block->mr->align);
#if defined(__s390x__)
if (kvm_enabled()) {
block->mr->align = MAX(block->mr->align, QEMU_VMALLOC_ALIGN);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 99e0f54d86..05d3d0da3b 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -441,6 +441,7 @@ void memory_region_init_resizeable_ram(MemoryRegion *mr,
* @name: Region name, becomes part of RAMBlock name used in migration stream
* must be unique within any device
* @size: size of the region.
+ * @align: alignment of the region.
* @share: %true if memory must be mmaped with the MAP_SHARED flag
* @path: the path in which to allocate the RAM.
* @errp: pointer to Error*, to store an error if it happens.
@@ -449,6 +450,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
struct Object *owner,
const char *name,
uint64_t size,
+ uint64_t align,
bool share,
const char *path,
Error **errp);
diff --git a/memory.c b/memory.c
index b727f5ec0e..5165b9aa08 100644
--- a/memory.c
+++ b/memory.c
@@ -1386,6 +1386,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
struct Object *owner,
const char *name,
uint64_t size,
+ uint64_t align,
bool share,
const char *path,
Error **errp)
@@ -1394,6 +1395,7 @@ void memory_region_init_ram_from_file(MemoryRegion *mr,
mr->ram = true;
mr->terminates = true;
mr->destructor = memory_region_destructor_ram;
+ mr->align = align;
mr->ram_block = qemu_ram_alloc_from_file(size, mr, share, path, errp);
mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
}
diff --git a/numa.c b/numa.c
index ca731455e9..39a25aa1d2 100644
--- a/numa.c
+++ b/numa.c
@@ -541,7 +541,7 @@ static void allocate_system_memory_nonnuma(MemoryRegion *mr, Object *owner,
if (mem_path) {
#ifdef __linux__
Error *err = NULL;
- memory_region_init_ram_from_file(mr, owner, name, ram_size, false,
+ memory_region_init_ram_from_file(mr, owner, name, ram_size, 0, false,
mem_path, &err);
if (err) {
error_report_err(err);
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device
2017-05-26 2:24 [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Haozhong Zhang
2017-05-26 2:24 ` [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment Haozhong Zhang
@ 2017-05-30 9:15 ` Stefan Hajnoczi
2017-05-31 6:12 ` Haozhong Zhang
1 sibling, 1 reply; 6+ messages in thread
From: Stefan Hajnoczi @ 2017-05-30 9:15 UTC (permalink / raw)
To: Haozhong Zhang
Cc: qemu-devel, Michael S. Tsirkin, Igor Mammedov, Xiao Guangrong,
Dan Williams
[-- Attachment #1: Type: text/plain, Size: 3283 bytes --]
On Fri, May 26, 2017 at 10:24:37AM +0800, Haozhong Zhang wrote:
> Applications in Linux guest that use device-dax never trigger flush
> that can be trapped by KVM/QEMU. Meanwhile, if the host backend is not
> device-dax, QEMU cannot guarantee the persistence of guest writes.
> Before solving this flushing problem, QEMU should warn users if the
> host backend is not device-dax.
>
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> Message-id: CAPcyv4hV2-ZW8SMCRtD0P_86KgR3DHOvNe+6T5SY2u7wXg3gEg@mail.gmail.com
> ---
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> Cc: Stefan Hajnoczi <stefanha@gmail.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> ---
> hw/mem/nvdimm.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
> index db896b0bb6..c7bb407f33 100644
> --- a/hw/mem/nvdimm.c
> +++ b/hw/mem/nvdimm.c
> @@ -26,6 +26,7 @@
> #include "qapi/error.h"
> #include "qapi/visitor.h"
> #include "hw/mem/nvdimm.h"
> +#include "qemu/error-report.h"
>
> static void nvdimm_get_label_size(Object *obj, Visitor *v, const char *name,
> void *opaque, Error **errp)
> @@ -78,12 +79,48 @@ static MemoryRegion *nvdimm_get_memory_region(PCDIMMDevice *dimm)
> return &nvdimm->nvdimm_mr;
> }
>
> +static void nvdimm_check_dax(HostMemoryBackend *hostmem)
> +{
> + char *mem_path =
> + object_property_get_str(OBJECT(hostmem), "mem-path", NULL);
> + char *dev_name = NULL, *sysfs_path = NULL;
> + bool is_dax = false;
> +
> + if (!mem_path) {
> + goto out;
> + }
> +
> + if (!g_str_has_prefix(mem_path, "/dev/dax")) {
Does not work with relative paths, symlinks, or device nodes in
non-standard locations.
A more accurate check is to fstat the file descriptor for the char
device major/minor number and verify that
/sys/dev/char/MAJ:MIN/device/devtype is "nd_dax".
> + goto out;
> + }
> +
> + dev_name = mem_path + strlen("/dev/");
> + sysfs_path = g_strdup_printf("/sys/class/dax/%s", dev_name);
> + if (access(sysfs_path, F_OK)) {
> + goto out;
> + }
> +
> + is_dax = true;
This check is Linux-specific, please use #ifdef __linux__. It's okay to
always print an error on other operating systems.
> +
> + out:
> + if (!is_dax) {
> + error_report("warning: nvdimm backend %s is not DAX device, "
The check is not 100% accurate so:
s/is not/does not look like a/
> + "unable to guarantee persistence of guest writes",
> + mem_path ?: "RAM");
> + }
> +
> + g_free(sysfs_path);
> + g_free(mem_path);
> +}
> +
> static void nvdimm_realize(PCDIMMDevice *dimm, Error **errp)
> {
> MemoryRegion *mr = host_memory_backend_get_memory(dimm->hostmem, errp);
> NVDIMMDevice *nvdimm = NVDIMM(dimm);
> uint64_t align, pmem_size, size = memory_region_size(mr);
>
> + nvdimm_check_dax(dimm->hostmem);
> +
> align = memory_region_get_alignment(mr);
>
> pmem_size = size - nvdimm->label_size;
> --
> 2.11.0
>
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment
2017-05-26 2:24 ` [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment Haozhong Zhang
@ 2017-05-30 9:16 ` Stefan Hajnoczi
2017-05-31 6:24 ` Haozhong Zhang
0 siblings, 1 reply; 6+ messages in thread
From: Stefan Hajnoczi @ 2017-05-30 9:16 UTC (permalink / raw)
To: Haozhong Zhang
Cc: qemu-devel, Eduardo Habkost, Igor Mammedov, Paolo Bonzini,
Peter Crosthwaite, Richard Henderson, Xiao Guangrong,
Dan Williams
[-- Attachment #1: Type: text/plain, Size: 752 bytes --]
On Fri, May 26, 2017 at 10:24:38AM +0800, Haozhong Zhang wrote:
> file_ram_alloc() currently maps the backend file via mmap to a virtual
> address aligned to the value returned by qemu_fd_getpagesize(). When a
> DAX device (e.g. /dev/dax0.0) is used as the backend file, its kernel
> mmap implementation may require an alignment larger than what
> qemu_fd_get_pagesize() returns (e.g. 2MB vs. 4KB), and mmap may fail.
>
> This commit adds an attribute 'align' to hostmem-file, so that users
> can specify a proper alignment that satisfies the kernel requirement.
>
> If 'align' is not specified or is 0, the value returned by
> qemu_fd_get_pagesize() will be used as before.
How are users supposed to determine alignment requirements?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 455 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device
2017-05-30 9:15 ` [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Stefan Hajnoczi
@ 2017-05-31 6:12 ` Haozhong Zhang
0 siblings, 0 replies; 6+ messages in thread
From: Haozhong Zhang @ 2017-05-31 6:12 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: qemu-devel, Michael S. Tsirkin, Igor Mammedov, Xiao Guangrong,
Dan Williams
On 05/30/17 10:15 +0100, Stefan Hajnoczi wrote:
> On Fri, May 26, 2017 at 10:24:37AM +0800, Haozhong Zhang wrote:
> > Applications in Linux guest that use device-dax never trigger flush
> > that can be trapped by KVM/QEMU. Meanwhile, if the host backend is not
> > device-dax, QEMU cannot guarantee the persistence of guest writes.
> > Before solving this flushing problem, QEMU should warn users if the
> > host backend is not device-dax.
> >
> > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> > Message-id: CAPcyv4hV2-ZW8SMCRtD0P_86KgR3DHOvNe+6T5SY2u7wXg3gEg@mail.gmail.com
> > ---
> > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > Cc: Igor Mammedov <imammedo@redhat.com>
> > Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> > Cc: Stefan Hajnoczi <stefanha@gmail.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > ---
> > hw/mem/nvdimm.c | 37 +++++++++++++++++++++++++++++++++++++
> > 1 file changed, 37 insertions(+)
> >
> > diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
> > index db896b0bb6..c7bb407f33 100644
> > --- a/hw/mem/nvdimm.c
> > +++ b/hw/mem/nvdimm.c
> > @@ -26,6 +26,7 @@
> > #include "qapi/error.h"
> > #include "qapi/visitor.h"
> > #include "hw/mem/nvdimm.h"
> > +#include "qemu/error-report.h"
> >
> > static void nvdimm_get_label_size(Object *obj, Visitor *v, const char *name,
> > void *opaque, Error **errp)
> > @@ -78,12 +79,48 @@ static MemoryRegion *nvdimm_get_memory_region(PCDIMMDevice *dimm)
> > return &nvdimm->nvdimm_mr;
> > }
> >
> > +static void nvdimm_check_dax(HostMemoryBackend *hostmem)
> > +{
> > + char *mem_path =
> > + object_property_get_str(OBJECT(hostmem), "mem-path", NULL);
> > + char *dev_name = NULL, *sysfs_path = NULL;
> > + bool is_dax = false;
> > +
> > + if (!mem_path) {
> > + goto out;
> > + }
> > +
> > + if (!g_str_has_prefix(mem_path, "/dev/dax")) {
>
> Does not work with relative paths, symlinks, or device nodes in
> non-standard locations.
>
> A more accurate check is to fstat the file descriptor for the char
> device major/minor number and verify that
> /sys/dev/char/MAJ:MIN/device/devtype is "nd_dax".
>
Yes, Dan also suggested to use this approach. I'll turn to it in v2.
> > + goto out;
> > + }
> > +
> > + dev_name = mem_path + strlen("/dev/");
> > + sysfs_path = g_strdup_printf("/sys/class/dax/%s", dev_name);
> > + if (access(sysfs_path, F_OK)) {
> > + goto out;
> > + }
> > +
> > + is_dax = true;
>
> This check is Linux-specific, please use #ifdef __linux__. It's okay to
> always print an error on other operating systems.
>
will change
> > +
> > + out:
> > + if (!is_dax) {
> > + error_report("warning: nvdimm backend %s is not DAX device, "
>
> The check is not 100% accurate so:
>
> s/is not/does not look like a/
ditto
Thanks,
Haozhong
>
> > + "unable to guarantee persistence of guest writes",
> > + mem_path ?: "RAM");
> > + }
> > +
> > + g_free(sysfs_path);
> > + g_free(mem_path);
> > +}
> > +
> > static void nvdimm_realize(PCDIMMDevice *dimm, Error **errp)
> > {
> > MemoryRegion *mr = host_memory_backend_get_memory(dimm->hostmem, errp);
> > NVDIMMDevice *nvdimm = NVDIMM(dimm);
> > uint64_t align, pmem_size, size = memory_region_size(mr);
> >
> > + nvdimm_check_dax(dimm->hostmem);
> > +
> > align = memory_region_get_alignment(mr);
> >
> > pmem_size = size - nvdimm->label_size;
> > --
> > 2.11.0
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment
2017-05-30 9:16 ` Stefan Hajnoczi
@ 2017-05-31 6:24 ` Haozhong Zhang
0 siblings, 0 replies; 6+ messages in thread
From: Haozhong Zhang @ 2017-05-31 6:24 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: qemu-devel, Eduardo Habkost, Igor Mammedov, Paolo Bonzini,
Peter Crosthwaite, Richard Henderson, Xiao Guangrong,
Dan Williams
On 05/30/17 10:16 +0100, Stefan Hajnoczi wrote:
> On Fri, May 26, 2017 at 10:24:38AM +0800, Haozhong Zhang wrote:
> > file_ram_alloc() currently maps the backend file via mmap to a virtual
> > address aligned to the value returned by qemu_fd_getpagesize(). When a
> > DAX device (e.g. /dev/dax0.0) is used as the backend file, its kernel
> > mmap implementation may require an alignment larger than what
> > qemu_fd_get_pagesize() returns (e.g. 2MB vs. 4KB), and mmap may fail.
> >
> > This commit adds an attribute 'align' to hostmem-file, so that users
> > can specify a proper alignment that satisfies the kernel requirement.
> >
> > If 'align' is not specified or is 0, the value returned by
> > qemu_fd_get_pagesize() will be used as before.
>
> How are users supposed to determine alignment requirements?
As discussed in another thread [1,2], the alignment of device-dax can
be got from /sys/dev/char/$major:$minor/device/align, and I'll let
QEMU read the value from it instead of user input.
[1] https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg06235.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg06189.html
Haozhong
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2017-05-26 2:24 [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Haozhong Zhang
2017-05-26 2:24 ` [Qemu-devel] [PATCH 2/2] hostmem-file: add an attribute 'align' to set its alignment Haozhong Zhang
2017-05-30 9:16 ` Stefan Hajnoczi
2017-05-31 6:24 ` Haozhong Zhang
2017-05-30 9:15 ` [Qemu-devel] [PATCH 1/2] nvdimm: warn if the backend is not a DAX device Stefan Hajnoczi
2017-05-31 6:12 ` Haozhong Zhang
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