[PATCH v3 0/2] KVM: arm64: Support for per-guest fine grained traps configuration

[Mark Brown]

A number of upcoming features will require per guest configuration of
the fine grained traps enabled in the guest.  At present the only
management we do is for SME where we don't yet have guest support so we
unconditionally enable the traps while guests are running but this will
change going forward and at present the code isn't particularly
scalable.  This series aims to make it easier to configure which traps
are enabled for the guest by making the value set for the guest into
configuration in the vCPU data which we can set up based on the chosen
features rather than requiring conditional code in the trap enable and
disable paths.

This will have no benefit until one of the features that requires
configuration of these traps is merged but since there's a number of
such features it seems useful to decide on an approach to handling traps
for them which can be shared.

Changes in v3:
- Move the HFGxTR_EL2 storage from the sys_regs array to a member
  variable directly in struct kvm_vcpu_context.
- Link to v2: https://lore.kernel.org/r/20230301-kvm-arm64-fgt-v2-0-c11c0dcf810a@kernel.org
Changes in v2:
- List all the traps enabled by setting the registers to 0 by default.
- Save the HWFGxTR_EL2 valus in the vCPU/host sysreg structures.
- Link to v1: https://lore.kernel.org/r/20230301-kvm-arm64-fgt-v1-0-cfdf71ac67dc@kernel.org

---
Mark Brown (2):
      arm64: Add feature detection for fine grained traps
      KVM: arm64: Move FGT value configuration to vCPU state

 arch/arm64/include/asm/kvm_emulate.h    | 16 ++++++++++++++
 arch/arm64/include/asm/kvm_host.h       |  3 +++
 arch/arm64/kernel/cpufeature.c          | 11 ++++++++++
 arch/arm64/kvm/arm.c                    |  1 +
 arch/arm64/kvm/hyp/include/hyp/switch.h | 37 +++++++++++++++++++--------------
 arch/arm64/tools/cpucaps                |  1 +
 6 files changed, 53 insertions(+), 16 deletions(-)
---
base-commit: e8d018dd0257f744ca50a729e3d042cf2ec9da65
change-id: 20230301-kvm-arm64-fgt-e5dd12746f67

Best regards,
-- 
Mark Brown <broonie at kernel.org>