[v2] x86/svm: Add support for Bus Lock Threshold

[PATCH v2 0/3] x86/svm: Add support for Bus Lock Threshold

Alejandro Vallejo posted 3 patches 4 days, 15 hours ago

Diff against v1
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Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20260121142857.39069-1-alejandro.garciavallejo@amd.com

CHANGELOG.md                          |  3 +++
xen/arch/x86/hvm/svm/svm.c            |  6 ++++++
xen/arch/x86/hvm/svm/vmcb.c           |  3 +++
xen/arch/x86/hvm/svm/vmcb.h           | 15 +++++++++++++--
xen/arch/x86/include/asm/hvm/svm.h    |  2 ++
xen/arch/x86/include/asm/perfc_defn.h |  2 +-
6 files changed, 28 insertions(+), 3 deletions(-)

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[PATCH v2 0/3] x86/svm: Add support for Bus Lock Threshold

Posted by Alejandro Vallejo 4 days, 15 hours ago

Hi,

v1: https://lore.kernel.org/xen-devel/20260120095353.2778-1-alejandro.garciavallejo@amd.com
pipeline (in progress):
    https://gitlab.com/xen-project/people/agvallejo/xen/-/pipelines/2276726870

Original cover letter:

Bus Locks are very costly and a VM left unchecked spamming instructions that
lock the memory bus (e.g: unaligned atomic CAS) makes system perf take a
nosedive. This patch is similar to BLD of VMX, but for SVM. It configures all
VMRUNs so they automatically exit at the first encounter of a buslock event,
effectively rate-limiting them.

Cheers,
Alejandro

Alejandro Vallejo (3):
  x86/svm: Add infrastructure for Bus Lock Threshold
  x86/svm: Intercept Bus Locks for HVM guests
  CHANGELOG: Note the new SVM bus-lock intercept

 CHANGELOG.md                          |  3 +++
 xen/arch/x86/hvm/svm/svm.c            |  6 ++++++
 xen/arch/x86/hvm/svm/vmcb.c           |  3 +++
 xen/arch/x86/hvm/svm/vmcb.h           | 15 +++++++++++++--
 xen/arch/x86/include/asm/hvm/svm.h    |  2 ++
 xen/arch/x86/include/asm/perfc_defn.h |  2 +-
 6 files changed, 28 insertions(+), 3 deletions(-)


base-commit: 61204ed24ba4537d6eff56594faa5d23cacb8310
-- 
2.43.0