On Fri, 02 May 2025 05:03:41 +0000, Manali Shukla wrote:
Misbehaving guests can cause bus locks to degrade the performance of a system. Non-WB (write-back) and misaligned locked RMW (read-modify-write) instructions are referred to as "bus locks" and require system wide synchronization among all processors to guarantee the atomicity. The bus locks can impose notable performance penalties for all processors within the system.
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Applied to kvm-x86 svm, with a heavily modified test, and the comment typo fix for patch 4.
[1/5] KVM: x86: Make kvm_pio_request.linear_rip a common field for user exits https://github.com/kvm-x86/linux/commit/e9628b011bbd [2/5] x86/cpufeatures: Add CPUID feature bit for the Bus Lock Threshold https://github.com/kvm-x86/linux/commit/faad6645e112 [3/5] KVM: SVM: Add architectural definitions/assets for Bus Lock Threshold https://github.com/kvm-x86/linux/commit/827547bc3a2a [4/5] KVM: SVM: Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM CPUs https://github.com/kvm-x86/linux/commit/89f9edf4c69d [5/5] KVM: selftests: Add test to verify KVM_CAP_X86_BUS_LOCK_EXIT https://github.com/kvm-x86/linux/commit/72df72e1c6dd