Linux 6.19 Overhauling The Intel TDX Locking Code For KVM
- Reference: 0001594883
- News link: https://www.phoronix.com/news/Linux-6.19-Fixing-Intel-TDX-KVM
- Source link:
The KVM x86 TDX pull of new material for Linux 6.19 includes "a large overhaul of lock-related TDX code" for dealing with various locking contention issues with that Intel confidential computing security feature for VMs.
Christopherson explained of the TDX overhaul in the pull request:
"Overhaul the TDX code to address systemic races where KVM (acting on behalf of userspace) could inadvertantly trigger lock contention in the TDX-Module, which KVM was either working around in weird, ugly ways, or was simply oblivious to (as proven by Yan tripping several KVM_BUG_ON()s with clever selftests)."
That is part of [1]this TDX pull ahead of the Linux 6.19 merge window opening in early December.
Sean also sent out the queued AMD SVM changes too for KVM. [2]That pull includes various minor fixes, AVIC support for addressing 4K vCPUs in x2AVIC mode, and other small changes but seemingly nothing too exciting this round.
[3]Another pull for the KVM x86 code does add NUMA mempolicy support for guest_memfd that may be of interest to some users.
[1] https://lore.kernel.org/lkml/20251126014455.788131-8-seanjc@google.com/
[2] https://lore.kernel.org/lkml/20251126014455.788131-7-seanjc@google.com/
[3] https://lore.kernel.org/lkml/20251126014455.788131-3-seanjc@google.com/