[Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Haozhong Zhang]

Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
current region format interface code 0x201 indicates the block
addressed function interface 1, rather than a byte addressable
interface. Fix it by using 0x301 which indicates the byte addressable
no energy backed function interface 1.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
 hw/acpi/nvdimm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 8e7d6ec034..b5734f5897 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
     nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
                                              in ACPI 6.0 is 1. */);
     nfit_dcr->serial_number = cpu_to_le32(sn);
-    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
-                                         2: NVDIMM Device Specific Method
-                                         (DSM) in DSM Spec Rev1.*/);
+    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
+                                         Byte addressable, no energy backed.
+                                         See ACPI 6.2, sect 5.2.25.6 and
+                                         JEDEC Annex L Release 3. */);
 }
 
 static GArray *nvdimm_build_device_structure(void)
-- 
2.11.0

Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Stefan Hajnoczi]

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On Wed, Jun 07, 2017 at 04:06:39PM +0800, Haozhong Zhang wrote:
> Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
> current region format interface code 0x201 indicates the block
> addressed function interface 1, rather than a byte addressable
> interface. Fix it by using 0x301 which indicates the byte addressable
> no energy backed function interface 1.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> ---
>  hw/acpi/nvdimm.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Xiao Guangrong]

On 06/07/2017 04:06 PM, Haozhong Zhang wrote:
> Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
> current region format interface code 0x201 indicates the block
> addressed function interface 1, rather than a byte addressable
> interface. Fix it by using 0x301 which indicates the byte addressable
> no energy backed function interface 1.
> 
> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> ---
>   hw/acpi/nvdimm.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index 8e7d6ec034..b5734f5897 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
>       nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
>                                                in ACPI 6.0 is 1. */);
>       nfit_dcr->serial_number = cpu_to_le32(sn);
> -    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
> -                                         2: NVDIMM Device Specific Method
> -                                         (DSM) in DSM Spec Rev1.*/);
> +    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
> +                                         Byte addressable, no energy backed.
> +                                         See ACPI 6.2, sect 5.2.25.6 and
> +                                         JEDEC Annex L Release 3. */);

Shouldn't the 'no energy backend' indicator be set only for !dax disk?

Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Haozhong Zhang]

On 06/08/17 11:07 +0800, Xiao Guangrong wrote:
> 
> 
> On 06/07/2017 04:06 PM, Haozhong Zhang wrote:
> > Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
> > current region format interface code 0x201 indicates the block
> > addressed function interface 1, rather than a byte addressable
> > interface. Fix it by using 0x301 which indicates the byte addressable
> > no energy backed function interface 1.
> > 
> > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> > ---
> >   hw/acpi/nvdimm.c | 7 ++++---
> >   1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> > index 8e7d6ec034..b5734f5897 100644
> > --- a/hw/acpi/nvdimm.c
> > +++ b/hw/acpi/nvdimm.c
> > @@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
> >       nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
> >                                                in ACPI 6.0 is 1. */);
> >       nfit_dcr->serial_number = cpu_to_le32(sn);
> > -    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
> > -                                         2: NVDIMM Device Specific Method
> > -                                         (DSM) in DSM Spec Rev1.*/);
> > +    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
> > +                                         Byte addressable, no energy backed.
> > +                                         See ACPI 6.2, sect 5.2.25.6 and
> > +                                         JEDEC Annex L Release 3. */);
> 
> Shouldn't the 'no energy backend' indicator be set only for !dax disk?

Above specs define RFIC for two classes of byte-addressable NVDIMM:
1. 0x10[0|1]: A function containing byte addressable persistent memory
              whose persistence is achieved through the use of DRAM,
              nonvolatile memory (e.g., Flash) and an energy source.
	      Only the DRAM portion is addressable by the system.
2. 0x30[0|1]: A function containing byte addressable persistent
              memory. All of the persistent memory is addressable by
              the system. No external energy source is required.
If the last bit is 0, then it's a proprietary interface.

The external backed energy is a mechanism that implements the
persistence for the first class, and it's not required for the
second class.

The key point in this patch is RFIC provided by QEMU should indicate a
*byte addressable* NVDIMM. Whether it's backed by the external energy
does not matter much here, so I think it's free to choose one of them.

Haozhong

Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Xiao Guangrong]

On 06/08/2017 01:06 PM, Haozhong Zhang wrote:
> On 06/08/17 11:07 +0800, Xiao Guangrong wrote:
>>
>>
>> On 06/07/2017 04:06 PM, Haozhong Zhang wrote:
>>> Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
>>> current region format interface code 0x201 indicates the block
>>> addressed function interface 1, rather than a byte addressable
>>> interface. Fix it by using 0x301 which indicates the byte addressable
>>> no energy backed function interface 1.
>>>
>>> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
>>> ---
>>>    hw/acpi/nvdimm.c | 7 ++++---
>>>    1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
>>> index 8e7d6ec034..b5734f5897 100644
>>> --- a/hw/acpi/nvdimm.c
>>> +++ b/hw/acpi/nvdimm.c
>>> @@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
>>>        nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
>>>                                                 in ACPI 6.0 is 1. */);
>>>        nfit_dcr->serial_number = cpu_to_le32(sn);
>>> -    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
>>> -                                         2: NVDIMM Device Specific Method
>>> -                                         (DSM) in DSM Spec Rev1.*/);
>>> +    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
>>> +                                         Byte addressable, no energy backed.
>>> +                                         See ACPI 6.2, sect 5.2.25.6 and
>>> +                                         JEDEC Annex L Release 3. */);
>>
>> Shouldn't the 'no energy backend' indicator be set only for !dax disk?
> 
> Above specs define RFIC for two classes of byte-addressable NVDIMM:
> 1. 0x10[0|1]: A function containing byte addressable persistent memory
>                whose persistence is achieved through the use of DRAM,
>                nonvolatile memory (e.g., Flash) and an energy source.
> 	      Only the DRAM portion is addressable by the system.
> 2. 0x30[0|1]: A function containing byte addressable persistent
>                memory. All of the persistent memory is addressable by
>                the system. No external energy source is required.
> If the last bit is 0, then it's a proprietary interface.

As both of them indicate persistent memory, it is okay to me.

The FIC, 0x201, comes from the document of Intel DSM example, i have no idea why
it uses 0x201. Maybe it is worth being fixed too.

Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Haozhong Zhang]

On 06/08/17 14:40 +0800, Xiao Guangrong wrote:
> 
> 
> On 06/08/2017 01:06 PM, Haozhong Zhang wrote:
> > On 06/08/17 11:07 +0800, Xiao Guangrong wrote:
> > > 
> > > 
> > > On 06/07/2017 04:06 PM, Haozhong Zhang wrote:
> > > > Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
> > > > current region format interface code 0x201 indicates the block
> > > > addressed function interface 1, rather than a byte addressable
> > > > interface. Fix it by using 0x301 which indicates the byte addressable
> > > > no energy backed function interface 1.
> > > > 
> > > > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
> > > > ---
> > > >    hw/acpi/nvdimm.c | 7 ++++---
> > > >    1 file changed, 4 insertions(+), 3 deletions(-)
> > > > 
> > > > diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> > > > index 8e7d6ec034..b5734f5897 100644
> > > > --- a/hw/acpi/nvdimm.c
> > > > +++ b/hw/acpi/nvdimm.c
> > > > @@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
> > > >        nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
> > > >                                                 in ACPI 6.0 is 1. */);
> > > >        nfit_dcr->serial_number = cpu_to_le32(sn);
> > > > -    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
> > > > -                                         2: NVDIMM Device Specific Method
> > > > -                                         (DSM) in DSM Spec Rev1.*/);
> > > > +    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
> > > > +                                         Byte addressable, no energy backed.
> > > > +                                         See ACPI 6.2, sect 5.2.25.6 and
> > > > +                                         JEDEC Annex L Release 3. */);
> > > 
> > > Shouldn't the 'no energy backend' indicator be set only for !dax disk?
> > 
> > Above specs define RFIC for two classes of byte-addressable NVDIMM:
> > 1. 0x10[0|1]: A function containing byte addressable persistent memory
> >                whose persistence is achieved through the use of DRAM,
> >                nonvolatile memory (e.g., Flash) and an energy source.
> > 	      Only the DRAM portion is addressable by the system.
> > 2. 0x30[0|1]: A function containing byte addressable persistent
> >                memory. All of the persistent memory is addressable by
> >                the system. No external energy source is required.
> > If the last bit is 0, then it's a proprietary interface.
> 
> As both of them indicate persistent memory, it is okay to me.
> 
> The FIC, 0x201, comes from the document of Intel DSM example, i have no idea why
> it uses 0x201. Maybe it is worth being fixed too.
> 

I guess the reason is it's an example, e.g. "... describes an
*example* _DSM interface for NVDIMM Device with Region Format
Interface Code (RFIC) of 0x0201" at the beginning of Chapter 2.

Haozhong

Re: [Qemu-devel] [PATCH] nvdimm acpi: fix region format interface code

[Dan Williams]

On Wed, Jun 7, 2017 at 11:50 PM, Haozhong Zhang
<haozhong.zhang@intel.com> wrote:
> On 06/08/17 14:40 +0800, Xiao Guangrong wrote:
>>
>>
>> On 06/08/2017 01:06 PM, Haozhong Zhang wrote:
>> > On 06/08/17 11:07 +0800, Xiao Guangrong wrote:
>> > >
>> > >
>> > > On 06/07/2017 04:06 PM, Haozhong Zhang wrote:
>> > > > Per ACPI 6.2, section 5.2.25.6 and JEDEC Annex L Release 3, the
>> > > > current region format interface code 0x201 indicates the block
>> > > > addressed function interface 1, rather than a byte addressable
>> > > > interface. Fix it by using 0x301 which indicates the byte addressable
>> > > > no energy backed function interface 1.
>> > > >
>> > > > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
>> > > > ---
>> > > >    hw/acpi/nvdimm.c | 7 ++++---
>> > > >    1 file changed, 4 insertions(+), 3 deletions(-)
>> > > >
>> > > > diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
>> > > > index 8e7d6ec034..b5734f5897 100644
>> > > > --- a/hw/acpi/nvdimm.c
>> > > > +++ b/hw/acpi/nvdimm.c
>> > > > @@ -338,9 +338,10 @@ static void nvdimm_build_structure_dcr(GArray *structures, DeviceState *dev)
>> > > >        nfit_dcr->revision_id = cpu_to_le16(1 /* Current Revision supported
>> > > >                                                 in ACPI 6.0 is 1. */);
>> > > >        nfit_dcr->serial_number = cpu_to_le32(sn);
>> > > > -    nfit_dcr->fic = cpu_to_le16(0x201 /* Format Interface Code. See Chapter
>> > > > -                                         2: NVDIMM Device Specific Method
>> > > > -                                         (DSM) in DSM Spec Rev1.*/);
>> > > > +    nfit_dcr->fic = cpu_to_le16(0x301 /* Format Interface Code:
>> > > > +                                         Byte addressable, no energy backed.
>> > > > +                                         See ACPI 6.2, sect 5.2.25.6 and
>> > > > +                                         JEDEC Annex L Release 3. */);
>> > >
>> > > Shouldn't the 'no energy backend' indicator be set only for !dax disk?
>> >
>> > Above specs define RFIC for two classes of byte-addressable NVDIMM:
>> > 1. 0x10[0|1]: A function containing byte addressable persistent memory
>> >                whose persistence is achieved through the use of DRAM,
>> >                nonvolatile memory (e.g., Flash) and an energy source.
>> >           Only the DRAM portion is addressable by the system.
>> > 2. 0x30[0|1]: A function containing byte addressable persistent
>> >                memory. All of the persistent memory is addressable by
>> >                the system. No external energy source is required.
>> > If the last bit is 0, then it's a proprietary interface.
>>
>> As both of them indicate persistent memory, it is okay to me.
>>
>> The FIC, 0x201, comes from the document of Intel DSM example, i have no idea why
>> it uses 0x201. Maybe it is worth being fixed too.
>>
>
> I guess the reason is it's an example, e.g. "... describes an
> *example* _DSM interface for NVDIMM Device with Region Format
> Interface Code (RFIC) of 0x0201" at the beginning of Chapter 2.

The 0x201 vs 0x301 distinction is blk-aperture mode vs pmem mode
namespaces. Other operating systems need this indication in the NFIT
DIMM Control Region, Linux doesn't care and just uses the presence of
blk-aperture tables as the indicator to whether  a control region
represent blk-mode vs pmem.