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[Xen-devel] [PATCH 0/5] xen/arm64: Branch predictor hardening (XSA-254 variant 2)

Hi all,

This series provides a framework for mitigating branch predictor hardening on
Arm64 on exception entry.

It also implements a dummy PSCI "VERSION" call as the hook for affected
Cortex-A CPUs. This will invalidate the predictor state with the latest
Arm Trusted Firmware patches which will appear at [1] and SoC vendors
with affected CPUs are strongly encouraged to update. We plan to switch to a
more efficient, special-purpose call when it is available and the PSCI spec
has been updated accordingly.

For more information about the impact of this issue and the software mitigations
for Arm processors, please see http://www.arm.com/security-update.


Julien Grall (5):
  xen/arm: Introduce enable callback to enable a capabilities on each
    online CPU
  xen/arm64: Add missing MIDR values for Cortex-A72, A73 and A75
  xen/arm: cpuerrata: Add MIDR_ALL_VERSIONS
  xen/arm64: Add skeleton to harden the branch predictor aliasing
  xen/arm64: Implement branch predictor hardening for affected Cortex-A

 xen/arch/arm/Kconfig             |  20 ++++
 xen/arch/arm/arm64/Makefile      |   1 +
 xen/arch/arm/arm64/bpi.S         |  89 +++++++++++++++++
 xen/arch/arm/cpuerrata.c         | 203 +++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/cpufeature.c        |  29 ++++++
 xen/arch/arm/setup.c             |   1 +
 xen/arch/arm/traps.c             |   5 +-
 xen/include/asm-arm/cpuerrata.h  |   2 +
 xen/include/asm-arm/cpufeature.h |   6 +-
 xen/include/asm-arm/processor.h  |  11 ++-
 10 files changed, 363 insertions(+), 4 deletions(-)
 create mode 100644 xen/arch/arm/arm64/bpi.S


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