[PATCH 0/2] Add support for the ERAPS feature

Amit Shah
2024-10-31T15:39:34Z

From: Amit Shah <amit.shah@amd.com>

Newer AMD CPUs (Turin+) have the ERAPS feature bit that allows us to remove
the RSB filling loops required during context switches and VM exits.

This patchset implements the feature to:
* remove the need for RSB filling on context switches and VMEXITs in host and
guests
* allow KVM guests to use the full default RSB stack

Amit Shah (2):
x86: cpu/bugs: add support for AMD ERAPS feature
x86: kvm: svm: add support for ERAPS and FLUSH_RAP_ON_VMRUN

Documentation/admin-guide/hw-vuln/spectre.rst | 5 ++-
arch/x86/include/asm/cpufeatures.h | 1 +
arch/x86/include/asm/nospec-branch.h | 11 +++++
arch/x86/include/asm/svm.h | 6 ++-
arch/x86/kernel/cpu/bugs.c | 36 ++++++++++-----
arch/x86/kvm/cpuid.c | 15 ++++++-
arch/x86/kvm/svm/svm.c | 44 +++++++++++++++++++
arch/x86/kvm/svm/svm.h | 15 +++++++
8 files changed, 118 insertions(+), 15 deletions(-)

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2.47.0