The subject prefix should be "[PATCH 6.6 0/5]" so people know right up
front where this is going.

On Wed, Jul 01, 2026 at 08:43:37PM +0000, Colton Lewis wrote:

This series backports VHE CPU boot fixes to the 6.6.y stable branch.

These fixes are already present in the 6.12.y stable branch (and
newer), but are missing in 6.6.y. They are required to enable booting
L1 guests with nested virtualization enabled (kvm-arm.mode=nested).

It's a bit worse than this. The architecture retroactively made
FEAT_E2H0 an optional feature, there are now implementations in the wild
that do not support the feature.

Without these patches, a 6.6.y guest boots with HCR_EL2.E2H
incorrectly configured (because it misses VHE-only detection or early
initialization), causing early boot hangs/trap loops.

Conflict resolutions:
- Patch 4 (KVM: arm64: Initialize HCR_EL2.E2H early) had conflicts in
  arch/arm64/kvm/hyp/nvhe/hyp-init.S due to differences in state
  initialization. Resolved by extracting EL2 state initialization into
  __kvm_init_el2_state.
- Patch 5 (arm64: Revamp HCR_EL2.E2H RES1 detection) had conflicts in
  arch/arm64/include/asm/el2_setup.h. Resolved by using raw msr hcr_el2
  instead of the missing msr_hcr_el2 macro.


Marc Zyngier (4):
  arm64: sysreg: Add layout for ID_AA64MMFR4_EL1
  arm64: Treat HCR_EL2.E2H as RES1 when ID_AA64MMFR4_EL1.E2H0 is
    negative
  arm64: Fix early handling of FEAT_E2H0 not being implemented
  arm64: Revamp HCR_EL2.E2H RES1 detection

Mark Rutland (1):
  KVM: arm64: Initialize HCR_EL2.E2H early

 arch/arm64/include/asm/el2_setup.h | 52 ++++++++++++++++++++++++++++++
 arch/arm64/kernel/head.S           | 17 +++-------
 arch/arm64/kvm/hyp/nvhe/hyp-init.S | 16 +++++++--
 arch/arm64/tools/sysreg            | 37 +++++++++++++++++++++
 4 files changed, 107 insertions(+), 15 deletions(-)


base-commit: d1cfde2d5d15be14123bdd1689162bd27f995a90
--
2.55.0.rc2.803.g1fd1e6609c-goog