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

[Amit Shah <amit@kernel.org>]

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(-)

-- 
2.47.0