Linux Kernel Updated To Add Zenbleed Fix For Valve's Steam Deck

Last month when the Linux kernel was mitigated for Zenbleed as a CPU vulnerability affecting AMD Zen 2 processors, it turns out the Steam Deck APU was accidentally left without coverage. An x86/urgent pull request sent out today for the Linux 6.5 kernel and for back-porting to current stable Linux kernel releases will extend the Zenbleed mitigation to protect Steam Deck gamers.

Sent out this morning for merging ahead of Linux 6.5-rc6 on Sunday is this x86/urgent pull. Most notable with these fixes is adding models 0x90-0x91 to the range of AMD Zenbleed-affected Zen 2 processors. It looks like the Steam Deck's custom APU was just accidentally left out in the original Zenbleed patch.

The patch notes that this AMD Custom APU 0405 coverage is specifically for the Steam Deck after it was accidentally left out from the original Linux Zenbleed patch although is "clearly affected by the vulnerability." This patch enables the Zenbleed fallback fix until a proper CPU microcode update is available for the Steam Deck.

Zenbleed (CVE-2023-20593) was disclosed last month after this data leakage vulnerability was discovered by a Google researcher. This Zenbleed coverage for the Steam Deck APU will hit Linux Git this weekend for v6.5-rc6 and then should be picked up by the various Linux kernel stable branches over the next few days.

In addition to the x86/urgent pull request this morning, an x86/bugs pull request was also sent out today with an initial round of fixes/cleanups for this week's AMD Inception (SRSO) and Intel Downfall mitigation patches. In case you missed it see my Intel Downfall mitigation benchmarks. I'll have out AMD Inception performance impact benchmarks in the next few days - there is an impact with Inception.