Re: [PATCH v2 00/15] KVM: arm64: nv: FPSIMD/SVE, plus some other CPTR goodies

Marc Zyngier
2024-06-14T13:36:16Z

On Thu, 13 Jun 2024 21:17:41 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
>
> As discussed, here's the combined series of Marc + I's patches that
> implement all the trap forwarding / merging logic required to observe
> the L1 CPTR configuration when running an L2 guest.
>
> Like before, this was tested on Neoverse-V2 with L0, L1, and L2 running
> fpsimd-test and sve-test on top of one another.
>
> v1 [1] -> v2:
> - Grab Marc's CPTR trap patches [2]
> - Avoid taking two traps when L1 accesses ZCR_EL2 while the host owns
> FP regs. The fast path will now load the FP regs and forward the
> sysreg trap to the slow path for complete handling.
> - Add a comment describing the above behavior (Marc)
> - Avoid the use of guest_hyp_*_traps_enabled() in
> __activate_cptr_traps() for better codegen (Marc)
> - Document the reason for only testing bit[0] of CPTR_EL2.xEN when
> folding L1 traps into the hardware CPTR value.
> - Add a helper for synthesizing SVE traps, rather than open-coding the
> ESR value in access_zcr_el2()
>
> [1]: https://lore.kernel.org/kvmarm/20240531231358.1000039-1-oliver.upton@linux.dev/
> [2]: https://lore.kernel.org/kvmarm/20240604130553.199981-1-maz@kernel.org/
>
> Jintack Lim (1):
> KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
>
> Marc Zyngier (4):
> KVM: arm64: nv: Handle CPACR_EL1 traps
> KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper
> KVM: arm64: nv: Add trap description for CPTR_EL2
> KVM: arm64: nv: Add additional trap setup for CPTR_EL2
>
> Oliver Upton (10):
> KVM: arm64: nv: Forward SVE traps to guest hypervisor
> KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
> KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
> KVM: arm64: nv: Handle ZCR_EL2 traps
> KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
> KVM: arm64: nv: Use guest hypervisor's max VL when running nested
> guest
> KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
> KVM: arm64: Spin off helper for programming CPTR traps
> KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
> KVM: arm64: Allow the use of SVE+NV
>
> arch/arm64/include/asm/kvm_emulate.h | 55 +++++++++
> arch/arm64/include/asm/kvm_host.h | 7 ++
> arch/arm64/include/asm/kvm_nested.h | 5 +-
> arch/arm64/kvm/arm.c | 5 -
> arch/arm64/kvm/emulate-nested.c | 91 ++++++++++++++
> arch/arm64/kvm/fpsimd.c | 22 +++-
> arch/arm64/kvm/handle_exit.c | 19 ++-
> arch/arm64/kvm/hyp/include/hyp/switch.h | 24 +++-
> arch/arm64/kvm/hyp/vhe/switch.c | 156 ++++++++++++++++++++----
> arch/arm64/kvm/nested.c | 3 +-
> arch/arm64/kvm/sys_regs.c | 38 ++++++
> 11 files changed, 380 insertions(+), 45 deletions(-)

Patches 1,5,7 may require some very minor rework, but they are
functionally correct AFAICT. Patches 3,12-14 do not warrant my RB.

For patches 1-2,4-11,15, and with the bisection issue fixed:

Reviewed-by: Marc Zyngier <maz@kernel.org>

M.

--
Without deviation from the norm, progress is not possible.