[00/10] KVM: arm64: Enable SVE support on nVHE systems

Message

Marc Zyngier March 16, 2021, 10:13 a.m. UTC

This series enables SVE support for KVM on nVHE hardware (or more
likely, software models), and is an alternative to Daniel's patch[1]
which has gone through 3 versions, but still has a number of issues.

Instead of waiting for things to happen, I decided to try and see what
I could come up with.

The SVE save/restore is modelled after the SVE VHE flow, itself
closely following the FPSIMD flow:

- the guest traps to EL2 on first SVE access, and will not trap
  anymore until vcpu_put()

- ZCR_EL2 stays constant as long as the guest has SVE enabled

- on vcpu_put(), ZCR_EL2 is restored to the default value

Most of this series only repaints things so that VHE and nVHE look as
similar as possible, the ZCR_EL2 management being the most visible
exception. This results in a bunch of preparatory patches that aim at
making the code slightly more readable.

This has been tested on a FVP model with both VHE.nVHE configurations
using the string tests included with the "optimized-routines"
library[2].

Patches against 5.12-rc2.

[1] https://lore.kernel.org/r/[e-mail]
[2] https://github.com/ARM-software/optimized-routines

Daniel Kiss (1):
  KVM: arm64: Enable SVE support for nVHE

Marc Zyngier (9):
  KVM: arm64: Provide KVM's own save/restore SVE primitives
  KVM: arm64: Use {read,write}_sysreg_el1 to access ZCR_EL1
  KVM: arm64: Let vcpu_sve_pffr() handle HYP VAs
  KVM: arm64: Introduce vcpu_sve_vq() helper
  KVM: arm64: Rework SVE host-save/guest-restore
  KVM: arm64: Map SVE context at EL2 when available
  KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state
  KVM: arm64: Add a nVHE-specific SVE VQ reset hypercall
  KVM: arm64: Save/restore SVE state for nVHE

 arch/arm64/Kconfig                      |  7 ---
 arch/arm64/include/asm/fpsimdmacros.h   | 10 +++-
 arch/arm64/include/asm/kvm_asm.h        |  1 +
 arch/arm64/include/asm/kvm_host.h       | 25 +++-----
 arch/arm64/include/asm/kvm_hyp.h        |  2 +
 arch/arm64/kvm/arm.c                    |  5 --
 arch/arm64/kvm/fpsimd.c                 | 31 ++++++++--
 arch/arm64/kvm/guest.c                  |  6 +-
 arch/arm64/kvm/hyp/fpsimd.S             | 10 ++++
 arch/arm64/kvm/hyp/include/hyp/switch.h | 78 ++++++++++++-------------
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      |  8 +++
 arch/arm64/kvm/hyp/nvhe/switch.c        |  4 +-
 arch/arm64/kvm/reset.c                  |  4 --
 13 files changed, 107 insertions(+), 84 deletions(-)