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Phoronix

Linux 7.1, Linux 7.2 Performance On The Intel Xeon 600 Series

With Linux 7.2 expected for its stable release this weekend, today's testing has some additional testing of the Linux 7.2 Git kernel as well as Linux 7.1 stable compared to Linux 7.0 as used by default on Ubuntu 26.04 LTS. Phoronix testing previously conducted of Linux 7.2 have shown benefits for Intel Arc B390 Xe3 in some configurations, faster poll performance on AMD Ryzen Threadripper and other hardware, and some nice I/O performance gains on AMD EPYC Turin. Today's kernel benchmarks are with the Intel Xeon 678X Granite Rapids WS currently in the lab as part of the HP Z4 G6i workstation testing.

Phoronix

Patches Posted For Fixing The Linux DRM Scheduler's Fair Policy

Ahead of the Linux 7.2 kernel release expected out on Sunday, the Direct Rendering Manager (DRM) subsystem was forced to revert their "fair" scheduler policy default new for this kernel. Due to a last minute user-reported regression, FIFO returns as the default DRM scheduler policy for Linux 7.2. But patches are now available for addressing that regression and thus hopefully for Linux 7.3 there will be the fair scheduler becoming the default...

LWN.net

Domas: Bypassing memory protection with AMD's memory controllers

Christopher Domas has published a proof of concept with a description showing how to use AMD memory controllers' bank swizzle mode to bypass memory protection and read or write arbitrary data, including CPU microcode definitions and memory belonging to the platform security processor. Among other things, this allows code running at the kernel level to directly manipulate the meaning of processor instructions, potentially bypassing other security measures such as memory encryption and virtual machine isolation. This is not, strictly, unexpected behavior: it is documented in AMD's manual (on page 113 of that PDF). But the fact that it can be used to access arbitrary memory and thereby rewrite supposedly immutable parts of the computer's firmware without crashing the host machine seems like an unintentional side-effect of the design. Fortunately, since enabling bank swizzle mode requires kernel-level privileges, the vulnerability is not an immediate problem for most software. Still, it se