can't access RAM from PCIe device in Xeon

Software Tuning, Performance Optimization & Platform Monitoring

Discussion regarding monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform updating.

can't access RAM from PCIe device in Xeon

516 Views

Hello,

Is there an known issue of access Xeon's RAM from PCIe (DMA access) ? We observe the issue when using linux 4.x on E5 servers ?
We have this issue only with Xeon E5 + Linux, and using other Intel's chip there is no issue.
When we use the same BIOS, Chip, with windows , we manage to access RAM's from PCIe (DMA access).

I've tried to search and asked the question, but got no response.
Is it a known issue in this chip ? Why is it observed with Linux , but not with Windows ?
Should I upgrade BIOS or is it some BIOS parameter that I should configure ?

We also tried to get assistance from Intel's and from Linux kernel, but nothing helped understanding this issue.
https://bugzilla.kernel.org/show_bug.cgi?id=205701

We are struggling with this issue for a long time now,

Any suggestion about this issue will help,

Ran

Link Copied

0 Replies

Community support is provided during standard business hours (Monday to Friday 7AM - 5PM PST). Other contact methods are available here.

Intel does not verify all solutions, including but not limited to any file transfers that may appear in this community. Accordingly, Intel disclaims all express and implied warranties, including without limitation, the implied warranties of merchantability, fitness for a particular purpose, and non-infringement, as well as any warranty arising from course of performance, course of dealing, or usage in trade.

For more complete information about compiler optimizations, see our Optimization Notice.