How to translate a physical address to virtual address?

OSR_Community_User · June 11, 2003, 2:09am

Dear all,

if I got a physical address from my device, how can I access the memory pointed by it?
There is a function named mmGetVirtualForPhysical, but ddk says it is for internal use.
Can I use this function? or any other routines to do it?

Any suggestion is appreciated!
???

ldx
2003-06-11

Maxim_S_Shatskih · June 11, 2003, 9:44am

MmMapIoSpace is the correct function. Don’t forget to unmap then.

Max

----- Original Message -----
From: “ldx”
To: “NT Developers Interest List”
Sent: Wednesday, June 11, 2003 10:13 AM
Subject: [ntdev] How to translate a physical address to virtual
address?

> Dear all,
>
> if I got a physical address from my device, how can I access the
memory pointed by it?
> There is a function named mmGetVirtualForPhysical, but ddk says it
is for internal use.
> Can I use this function? or any other routines to do it?
>
> Any suggestion is appreciated!
> ¡¡¡¡
>
> ldx
> 2003-06-11
>
>
>
>
> —
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to
xxxxx@lists.osr.com
>

OSR_Community_User · June 11, 2003, 10:33am

hi,Maxim S. Shatskih,

MmMapIoSpace runs at passive level. I need translate it in dispatch level.
and I think this function is for iospace mapping to virtual address. right?
But I want to use the function for this case:
I put many physical addresses(requests) into a memory area and put the physical address of the area to
the register of my device, after the device finishes some requests, it moves the requests to a list pointed by another register.
Then I get completed requests from the list but can’t translate the requests to virtual address to access them. (This is done in a dpcforisr, executed at DISPATCH_LEVEL.)

Maybe I can use a workitem to do the completerequtest work. Then if MmMapIoSpace can translate physical to virtual address, the requests can be translated and be accessed.

I will try it.

Thanks a lot.
ldx
2003-06-11
======= original message=======

MmMapIoSpace is the correct function. Don’t forget to unmap then.

Max

----- Original Message -----
From: “ldx”
>To: “NT Developers Interest List”
>Sent: Wednesday, June 11, 2003 10:13 AM
>Subject: [ntdev] How to translate a physical address to virtual
>address?
>
>
>> Dear all,
>>
>> if I got a physical address from my device, how can I access the
>memory pointed by it?
>> There is a function named mmGetVirtualForPhysical, but ddk says it
>is for internal use.
>> Can I use this function? or any other routines to do it?
>>
>> Any suggestion is appreciated!
>> ???
>>
>> ldx
>> 2003-06-11
>>
>>
>>
>>
>> —
>> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
>> To unsubscribe send a blank email to
>xxxxx@lists.osr.com
>>
>
>
>
>—
>You are currently subscribed to ntdev as: ldxlq@263.net
>To unsubscribe send a blank email to xxxxx@lists.osr.com

= = = = = = = = = = = = = = = = = = = =

Maxim_S_Shatskih · June 11, 2003, 4:34pm

> MmMapIoSpace runs at passive level. I need translate it in
dispatch level.

Translate beforehand, before raising to DISPATCH.

and I think this function is for iospace mapping to virtual
address. right?

No, it creates a system PTE range with specified cache type for any
specified physical address.

I put many physical addresses(requests) into a memory area and put
the physical address of the area to
the register of my device, after the device finishes some requests,
it moves the requests to a list pointed by another register.

Classical design. I would suggest to maintain the parallel “virtual”
structures to “physical” ones. “Physical” are touched by the device,
and linked by physical addresses. “Virtual” are touched by software
only, and are linked by usual pointers.

It’s up to you how to find the “virtual” structure from the physical
one. For instance, allocate a common buffer - to be carved to
“physical” structures - and then a usual memory chunk, to be carved to
“virtual” ones. Then the offsets of the corresponding structures from
the beginning of their buffers will be the same.

Max

OSR_Community_User · June 11, 2003, 9:03pm

Thanks for your replying.

Your problem can be solved by building a data structure in your driver that
correlates the LOGICAL ADDRESSES you supplied to your device with the
original virtual address. Depending on the number of entries in this data
structure, this can be a linked list, a has table, or a lookaside table. You
search the table using the LOGICAL ADDRESS as the key to find your virtual
address.

You are right, but I want to find a better way to do this, because I think it will cause bad performance to search the table. Under Linux, there are two functions virt_to_bus and bus_to_virt, so I want to find the corresponding functions under NT.

I find another method to solve this. If I allocate a COMMON_BUFFER, then I can get the virtual address(assumed VA) and the LOGICAL_ADDRESS(assumed PA) of this buffer, then I put PA+offset=PEA to register and when the request finished, translate the PEA to VEA (virtual effective address, I just called it this.) by PEA-PA + VA=VEA.

Do u think the above can solve the problem?

Thanks again!

ldx
2003-6-12

--------------- 2003-06-11 You wrote---------------

Ldx,

It sounds like you are inventing your own DMA mechanism, and that is a REAL
BAD THING.

I suspect that Maxim assumed that you were referring to device memory,
instead it seems that you are referring to system memory. Transfers between
device and system memory initiated by the device (DMA) must use the defined
DMA mechanisms in NT. Read the DDK about how to perform DMA operations.

NT requires you to map physical addresses into what the DDK refers to as a
Logical Address. You must use either an MDL or a COMMON_BUFFER in order to
obtain a Logical Address, and you must have an AdapterObject in order to use
the MDL or allocate the COMMON_BUFFER.

Your problem can be solved by building a data structure in your driver that
correlates the LOGICAL ADDRESSES you supplied to your device with the
original virtual address. Depending on the number of entries in this data
structure, this can be a linked list, a has table, or a lookaside table. You
search the table using the LOGICAL ADDRESS as the key to find your virtual
address.

-----Original Message-----
From: ldx [mailto:ldxlq@263.net]
Sent: Tuesday, June 10, 2003 2:00 PM
To: NT Developers Interest List
Subject: [ntdev] Re: How to translate a physical address to virtual address?

hi,Maxim S. Shatskih,

MmMapIoSpace runs at passive level. I need translate it in dispatch level.
and I think this function is for iospace mapping to virtual address. right?
But I want to use the function for this case:
I put many physical addresses(requests) into a memory area and put
the physical address of the area to
the register of my device, after the device finishes some requests, it moves
the requests to a list pointed by another register.
Then I get completed requests from the list but can’t translate the
requests to virtual address to access them. (This is done in a dpcforisr,
executed at DISPATCH_LEVEL.)

Maybe I can use a workitem to do the completerequtest work. Then if
MmMapIoSpace can translate physical to virtual address, the requests can be
translated and be accessed.

I will try it.

Thanks a lot.
ldx
2003-06-11
======= original message=======

>MmMapIoSpace is the correct function. Don’t forget to unmap then.
>
> Max
>
>----- Original Message -----
>From: “ldx”
>>To: “NT Developers Interest List”
>>Sent: Wednesday, June 11, 2003 10:13 AM
>>Subject: [ntdev] How to translate a physical address to virtual
>>address?
>>
>>
>>> Dear all,
>>>
>>> if I got a physical address from my device, how can I access the
>>memory pointed by it?
>>> There is a function named mmGetVirtualForPhysical, but ddk says it
>>is for internal use.
>>> Can I use this function? or any other routines to do it?
>>>
>>> Any suggestion is appreciated!
>>> ???
>>>
>>> ldx
>>> 2003-06-11
>>>
>>>
>>>
>>>
>>> —
>>> You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
>>> unsubscribe send a blank email to
>>xxxxx@lists.osr.com
>>>
>>
>>
>>
>>—
>>You are currently subscribed to ntdev as: ldxlq@263.net
>>To unsubscribe send a blank email to xxxxx@lists.osr.com
>
>= = = = = = = = = = = = = = = = = = = =
>
>
>
>
>b???.???????v??ׯj??Dhuܬ???.?˛???m??֛???zf???y?ޞ?^?m=?b??(??(
>
>
>—
>You are currently subscribed to ntdev as: ldxlq@263.net
>To unsubscribe send a blank email to xxxxx@lists.osr.com

-----------------------------------------------------

OSR_Community_User · June 11, 2003, 9:06pm

yep - that method (common buffer offset) works just fine. Scsiport uses this for some things.

-p

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of ldx
Sent: Wednesday, June 11, 2003 5:00 PM
To: NT Developers Interest List
Subject: [ntdev] Re: How to translate a physical address to virtual address?

Thanks for your replying.

Your problem can be solved by building a data structure in your driver
that correlates the LOGICAL ADDRESSES you supplied to your device with
the original virtual address. Depending on the number of entries in
this data structure, this can be a linked list, a has table, or a
lookaside table. You search the table using the LOGICAL ADDRESS as the
key to find your virtual address.

You are right, but I want to find a better way to do this, because I think it will cause bad performance to search the table. Under Linux, there are two functions virt_to_bus and bus_to_virt, so I want to find the corresponding functions under NT.

I find another method to solve this. If I allocate a COMMON_BUFFER, then I can get the virtual address(assumed VA) and the LOGICAL_ADDRESS(assumed PA) of this buffer, then I put PA+offset=PEA to register and when the request finished, translate the PEA to VEA (virtual effective address, I just called it this.) by PEA-PA + VA=VEA.

Do u think the above can solve the problem?

Thanks again!

ldx
2003-6-12

--------------- 2003-06-11 You wrote---------------

Ldx,

It sounds like you are inventing your own DMA mechanism, and that is a
REAL BAD THING.

I suspect that Maxim assumed that you were referring to device memory,
instead it seems that you are referring to system memory. Transfers
between device and system memory initiated by the device (DMA) must use
the defined DMA mechanisms in NT. Read the DDK about how to perform DMA operations.

NT requires you to map physical addresses into what the DDK refers to
as a Logical Address. You must use either an MDL or a COMMON_BUFFER in
order to obtain a Logical Address, and you must have an AdapterObject
in order to use the MDL or allocate the COMMON_BUFFER.

Your problem can be solved by building a data structure in your driver
that correlates the LOGICAL ADDRESSES you supplied to your device with
the original virtual address. Depending on the number of entries in
this data structure, this can be a linked list, a has table, or a
lookaside table. You search the table using the LOGICAL ADDRESS as the
key to find your virtual address.

-----Original Message-----
From: ldx [mailto:ldxlq@263.net]
Sent: Tuesday, June 10, 2003 2:00 PM
To: NT Developers Interest List
Subject: [ntdev] Re: How to translate a physical address to virtual address?

hi,Maxim S. Shatskih,

MmMapIoSpace runs at passive level. I need translate it in dispatch level.
and I think this function is for iospace mapping to virtual address. right?
But I want to use the function for this case:
I put many physical addresses(requests) into a memory area and put the
physical address of the area to the register of my device, after the
device finishes some requests, it moves the requests to a list pointed
by another register.
Then I get completed requests from the list but can’t translate the
requests to virtual address to access them. (This is done in a
dpcforisr, executed at DISPATCH_LEVEL.)

Maybe I can use a workitem to do the completerequtest work. Then if
MmMapIoSpace can translate physical to virtual address, the requests
can be translated and be accessed.

I will try it.

Thanks a lot.
ldx
2003-06-11
======= original message=======

>MmMapIoSpace is the correct function. Don’t forget to unmap then.
>
> Max
>
>----- Original Message -----
>From: “ldx”
>>To: “NT Developers Interest List”
>>Sent: Wednesday, June 11, 2003 10:13 AM
>>Subject: [ntdev] How to translate a physical address to virtual
>>address?
>>
>>
>>> Dear all,
>>>
>>> if I got a physical address from my device, how can I access the
>>memory pointed by it?
>>> There is a function named mmGetVirtualForPhysical, but ddk says it
>>is for internal use.
>>> Can I use this function? or any other routines to do it?
>>>
>>> Any suggestion is appreciated!
>>>
>>>
>>> ldx
>>> 2003-06-11
>>>
>>>
>>>
>>>
>>> —
>>> You are currently subscribed to ntdev as: xxxxx@storagecraft.com To
>>> unsubscribe send a blank email to
>>xxxxx@lists.osr.com
>>>
>>
>>
>>
>>—
>>You are currently subscribed to ntdev as: ldxlq@263.net To unsubscribe
>>send a blank email to xxxxx@lists.osr.com
>
>= = = = = = = = = = = = = = = = = = = =
>
>
>
>
>b嫐.Ф\??辷?底痡?瓺hu墁抖??.炈洷殊m?澲洉╀zf?y炞^縨=?b槽(卜(
>
>
>—
>You are currently subscribed to ntdev as: ldxlq@263.net To unsubscribe
>send a blank email to xxxxx@lists.osr.com

-----------------------------------------------------

—
You are currently subscribed to ntdev as: xxxxx@microsoft.com To unsubscribe send a blank email to xxxxx@lists.osr.com

OSR_Community_User · June 11, 2003, 9:09pm

--------------- 2003-06-12 You wrote---------------

> MmMapIoSpace runs at passive level. I need translate it in
dispatch level.

Translate beforehand, before raising to DISPATCH.

> and I think this function is for iospace mapping to virtual
address. right?

No, it creates a system PTE range with specified cache type for any
specified physical address.

> I put many physical addresses(requests) into a memory area and put
the physical address of the area to
> the register of my device, after the device finishes some requests,
it moves the requests to a list pointed by another register.

Classical design. I would suggest to maintain the parallel “virtual”
structures to “physical” ones. “Physical” are touched by the device,
and linked by physical addresses. “Virtual” are touched by software
only, and are linked by usual pointers.

It’s up to you how to find the “virtual” structure from the physical
one. For instance, allocate a common buffer - to be carved to
“physical” structures - and then a usual memory chunk, to be carved to
“virtual” ones. Then the offsets of the corresponding structures from
the beginning of their buffers will be the same.

Very good. I want to do this, too. Thank you very much.

Max

You are currently subscribed to ntdev as: ldxlq@263.net
To unsubscribe send a blank email to xxxxx@lists.osr.com