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YulHan-2185 avatar image
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YulHan-2185 asked YuhanDeng-MSFT commented

This is a question about whether or not RAM is allocated according to Secure boot mode.

I am allocating and using RAM in the MFC program to use my own PCIE Card.
As a command used when allocating RAM, in Win Registry using RegSetValueEx() API (WinReg.h)
After setting BASEPHYSICALADDRESS, PHYSICALSIZE, BUFFERCOUNT,
I am using truncatememory as much as PHYSICALSIZE.
ex) "bcdedit.exe /set truncatememory 28168814592"

However, although it is a PC of the same brand, RAM is allocated or not according to the Secure Boot mode for each PC.
They are PCs with similar specifications, but for some reason, I inquire whether memory allocation is different depending on the Secure Boot mode.
Please also check whether it is related to the PC HW specification other than Windows.
Below are the PC specifications.

PC1) Memory can be allocated only when Secure boot mode is off
(P520, ThinkStation)
CPU: intel xeon w2145
RAM: 16GB PC4 ECC (single)
GPU: nvdia quadro p2200
Windows10 1909 // 18363.1440

PC2) Memory can be allocated regardless of Secure boot mode
(P520, ThinkStation)
CPU: intel xeon w2123
RAM: 8GB PC4 ECC (single)
GPU: nvdia quadro p400
Windows10 1909 // 18363.1440

In addition, can't memory be allocated in secure boot mode on because of the ECC function of RAM used in the Xeon main board?

windows-10-general
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Are developing a code using the C++?
Secure Boot won't change the RAM and this is unexpected behavior, you may try disable the Secure Boot, take a look at:
https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/disabling-secure-boot
And try and see if you are observing the same behavior?

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However, even in the secure boot mode on, the PC2 mentioned above will preempt the memory. If assigned, it will look like the picture below.99401-ram.png


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ram.png (5.9 KiB)

What exactly means "RAM is not allocated"?
Does your PCIe card driver crash or say something informative?

I am using truncatememory as much as PHYSICALSIZE.

Note that truncatememory parameter designates not the size, but the max. physical address that Windows uses. If you want to designate a size, use removememory.
Neither option is a supported way to allocate physical memory for a PCI device.

--pa


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"Unallocated" means that even if you use an instruction, the RAM you want to use is not allocated, like capture.
I allocate RAM to use the PCIE card I made, but it should be allocated by using the command that
only allocates RAM without attaching the PCIE card to the PC. However, it is not allocated on some PCs.99300-%E1%84%8C%E1%85%A1%E1%86%BC%E1%84%8E%E1%85%B5.png


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장치.png (61.8 KiB)

Hi,

I would like to check if the issue has been fixed? If yes, please help accept answer, so that others meet a similar issue can find useful information quickly. If you have any other concerns or questions, please feel free to feedback.

Best Regards,
Danny

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1 Answer

YuhanDeng-MSFT avatar image
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YuhanDeng-MSFT answered YuhanDeng-MSFT commented

Hi,
Maybe you can take a look at this:
https://software.intel.com/content/www/us/en/develop/articles/introduction-to-memory-bandwidth-allocation.html
Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.
As far as I’m concerned, for detailed information, I would suggest that you contact Intel for their support.

Thanks for your time.
Best regards,
Danny


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I contacted the main board manufacturer, but was told to contact MS.
So I asked here.
We haven't solved the problem yet, but we'll contact intel.

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Hi,
Ok. Let’s wait for the feedback. Please feel free to ask if there’s anything else we can offer.

Thanks for your understanding.
Best regards,
Danny

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