[nvmewin] Implementing a debug purpose Read/Write using IOCTL_SCSI_MINIPORT

[Mike Berhan]

Sagi,

 

The disk class driver is the one that divides reads and writes into smaller
requests.  It determines how to divide the request by querying the
STORAGE_ADAPTER_DESCRIPTOR.  STORPORT gets the information for this
structure from the miniport's PORT_CONFIGURATION_INFORMATION structure
(MaximumTransferLength and NumberOfPhysicalBreaks).

 

In reviewing the NVMe source code, it sets these values to max 128K with a
registry override available.  The INF file sets the override but it too
defaults to 128K:

 


HKR, Parameters\Device, MaxTXSize, %REG_DWORD%, 0x00020000 ; max trasnfer
size

 

Mike Berhan

busTRACE Technologies

1-208-629-4773 (Office)

 

From: nvmewin-bounces at lists.openfabrics.org
[mailto:nvmewin-bounces at lists.openfabrics.org] On Behalf Of Sagi Bar
Sent: Thursday, July 24, 2014 4:23 AM
To: Alex Chang; nvmewin at lists.openfabrics.org
Cc: Roman Goldshtein
Subject: Re: [nvmewin] Implementing a debug purpose Read/Write using
IOCTL_SCSI_MINIPORT

 

Hello Alex,

 

Thank you for your answer.

I see that the driver has a readily implemented NVMePreparePRPs(.) so adding
an extra command shouldn't be an issue.

 

I might need this feature in order to prevent the StorPort driver from
dividing the request into smaller SRBs (debug purposes).

 

Thank you, 

 

 

Sagi Bar
Test & Tools Staff FW Engineer

7 Atir Yeda St, Kfar - Saba 44425, Israel

sagi.bar at SanDisk.com <mailto:sagi.bar at SanDisk.com> 

 

From: Alex Chang [mailto:Alex.Chang at pmcs.com] 
Sent: Wednesday, July 23, 2014 2:35 AM
To: Sagi Bar; nvmewin at lists.openfabrics.org
<mailto:nvmewin at lists.openfabrics.org> 
Cc: Roman Goldshtein
Subject: RE: [nvmewin] Implementing a debug purpose Read/Write using
IOCTL_SCSI_MINIPORT

 

Hi Sagi,

 

Yes, you're right that it's due to security reasons and, in addition, you
may access the associated storage as a physical or formatted drive with
Windows supported APIs for your debugging purposes, like IOMeter does.

 

Thanks,

Alex

 

From: nvmewin-bounces at lists.openfabrics.org
<mailto:nvmewin-bounces at lists.openfabrics.org>
[mailto:nvmewin-bounces at lists.openfabrics.org] On Behalf Of Sagi Bar
Sent: Tuesday, July 22, 2014 5:21 AM
To: nvmewin at lists.openfabrics.org <mailto:nvmewin at lists.openfabrics.org> 
Cc: Roman Goldshtein
Subject: [nvmewin] Implementing a debug purpose Read/Write using
IOCTL_SCSI_MINIPORT

 

 

Hello Guys,

 

I would like to implement a debug purpose flow of performing NVME disk IO
bypassing the StorPort under Windows 8.1.

 

I thought about implementing it using "IOCTL_SCSI_MINIPORT" on host side and
adding code under "NVM_WRITE/ NVM_READ" on the target side.

 

I wonder whether anyone here has done it before and can share insights.

 

Moreover, Is there any particular reason why NVME READ/WRITE commands are
not implanted via IOCTL interface, except security ?

 

Thank you,

 

Sagi Bar
Test & Tools Staff FW Engineer

7 Atir Yeda St, Kfar - Saba 44425, Israel
sagi.bar at SanDisk.com <mailto:sagi.bar at SanDisk.com> 

 

 

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