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[0/8] KVM: arm64: Cleanup + fix to vCPU reset, feature flags

Message ID 20230920195036.1169791-1-oliver.upton@linux.dev (mailing list archive)
Headers show
Series KVM: arm64: Cleanup + fix to vCPU reset, feature flags | expand

Message

Oliver Upton Sept. 20, 2023, 7:50 p.m. UTC 
The way we do vCPU feature flag checks is a bit of a scattered mess
between the KVM_ARM_VCPU_INIT ioctl handler and kvm_reset_vcpu(). Let's
move all the feature flag checks up into the ioctl() handler to
eliminate failure paths from kvm_reset_vcpu(), as other usage of this
function no not handle returned errors.

Nobody screamed about the VM-wide feature flag change, so its also a
good time to rip out the vestiges of the vCPU-scoped bitmap.

I also spotted a bug with the NV feature flag where we allow it
regardless of system support.

Oliver Upton (8):
  KVM: arm64: Add generic check for system-supported vCPU features
  KVM: arm64: Hoist PMUv3 check into KVM_ARM_VCPU_INIT ioctl handler
  KVM: arm64: Hoist SVE check into KVM_ARM_VCPU_INIT ioctl handler
  KVM: arm64: Hoist PAuth checks into KVM_ARM_VCPU_INIT ioctl
  KVM: arm64: Prevent NV feature flag on systems w/o nested virt
  KVM: arm64: Hoist NV+SVE check into KVM_ARM_VCPU_INIT ioctl handler
  KVM: arm64: Remove unused return value from kvm_reset_vcpu()
  KVM: arm64: Get rid of vCPU-scoped feature bitmap

 arch/arm64/include/asm/kvm_emulate.h | 13 +++---
 arch/arm64/include/asm/kvm_host.h    |  5 +--
 arch/arm64/include/asm/kvm_nested.h  |  3 +-
 arch/arm64/kvm/arch_timer.c          |  4 +-
 arch/arm64/kvm/arm.c                 | 62 +++++++++++++++++++++-------
 arch/arm64/kvm/hypercalls.c          |  2 +-
 arch/arm64/kvm/reset.c               | 56 +++++--------------------
 include/kvm/arm_arch_timer.h         |  2 +-
 include/kvm/arm_pmu.h                |  2 +-
 include/kvm/arm_psci.h               |  2 +-
 10 files changed, 72 insertions(+), 79 deletions(-)


base-commit: ce9ecca0238b140b88f43859b211c9fdfd8e5b70

Comments

Marc Zyngier Sept. 21, 2023, 8:49 a.m. UTC | #1 
On Wed, 20 Sep 2023 20:50:28 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> The way we do vCPU feature flag checks is a bit of a scattered mess
> between the KVM_ARM_VCPU_INIT ioctl handler and kvm_reset_vcpu(). Let's
> move all the feature flag checks up into the ioctl() handler to
> eliminate failure paths from kvm_reset_vcpu(), as other usage of this
> function no not handle returned errors.
> 
> Nobody screamed about the VM-wide feature flag change, so its also a
> good time to rip out the vestiges of the vCPU-scoped bitmap.
> 
> I also spotted a bug with the NV feature flag where we allow it
> regardless of system support.

Thanks for going the extra mile refactoring this stuff. Apart from the
const/final nit, this looks good to me. It'd be good to have this in
-next shortly.

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

	M.
Oliver Upton Sept. 21, 2023, 6:18 p.m. UTC | #2 
On Wed, 20 Sep 2023 19:50:28 +0000, Oliver Upton wrote:
> The way we do vCPU feature flag checks is a bit of a scattered mess
> between the KVM_ARM_VCPU_INIT ioctl handler and kvm_reset_vcpu(). Let's
> move all the feature flag checks up into the ioctl() handler to
> eliminate failure paths from kvm_reset_vcpu(), as other usage of this
> function no not handle returned errors.
> 
> Nobody screamed about the VM-wide feature flag change, so its also a
> good time to rip out the vestiges of the vCPU-scoped bitmap.
> 
> [...]

Applied to kvmarm/next, with the change to use cpus_have_final_cap() per
Marc's suggestion.

[1/8] KVM: arm64: Add generic check for system-supported vCPU features
      https://git.kernel.org/kvmarm/kvmarm/c/ef150908b6bd
[2/8] KVM: arm64: Hoist PMUv3 check into KVM_ARM_VCPU_INIT ioctl handler
      https://git.kernel.org/kvmarm/kvmarm/c/9116db11feb5
[3/8] KVM: arm64: Hoist SVE check into KVM_ARM_VCPU_INIT ioctl handler
      https://git.kernel.org/kvmarm/kvmarm/c/be9c0c018389
[4/8] KVM: arm64: Hoist PAuth checks into KVM_ARM_VCPU_INIT ioctl
      https://git.kernel.org/kvmarm/kvmarm/c/baa28a53ddbe
[5/8] KVM: arm64: Prevent NV feature flag on systems w/o nested virt
      https://git.kernel.org/kvmarm/kvmarm/c/12405b09926f
[6/8] KVM: arm64: Hoist NV+SVE check into KVM_ARM_VCPU_INIT ioctl handler
      https://git.kernel.org/kvmarm/kvmarm/c/d99fb82fd35e
[7/8] KVM: arm64: Remove unused return value from kvm_reset_vcpu()
      https://git.kernel.org/kvmarm/kvmarm/c/3d4b2a4cddd7
[8/8] KVM: arm64: Get rid of vCPU-scoped feature bitmap
      https://git.kernel.org/kvmarm/kvmarm/c/1de10b7d13a9

--
Best,
Oliver