Merge branch kvm-arm64/sysreg-cleanup-5.20 into kvmarm-master/next

* kvm-arm64/sysreg-cleanup-5.20:
  : .
  : Long overdue cleanup of the sysreg userspace access,
  : with extra scrubbing on the vgic side of things.
  : From the cover letter:
  :
  : "Schspa Shi recently reported[1] that some of the vgic code interacting
  : with userspace was reading uninitialised stack memory, and although
  : that read wasn't used any further, it prompted me to revisit this part
  : of the code.
  :
  : Needless to say, this area of the kernel is pretty crufty, and shows a
  : bunch of issues in other parts of the KVM/arm64 infrastructure. This
  : series tries to remedy a bunch of them:
  :
  : - Sanitise the way we deal with sysregs from userspace: at the moment,
  :   each and every .set_user/.get_user callback has to implement its own
  :   userspace accesses (directly or indirectly). It'd be much better if
  :   that was centralised so that we can reason about it.
  :
  : - Enforce that all AArch64 sysregs are 64bit. Always. This was sort of
  :   implied by the code, but it took some effort to convince myself that
  :   this was actually the case.
  :
  : - Move the vgic-v3 sysreg userspace accessors to the userspace
  :   callbacks instead of hijacking the vcpu trap callback. This allows
  :   us to reuse the sysreg infrastructure.
  :
  : - Consolidate userspace accesses for both GICv2, GICv3 and common code
  :   as much as possible.
  :
  : - Cleanup a bunch of not-very-useful helpers, tidy up some of the code
  :   as we touch it.
  :
  : [1] https://lore.kernel.org/r/m2h740zz1i.fsf@gmail.com

"
  : .
  KVM: arm64: Get rid or outdated comments
  KVM: arm64: Descope kvm_arm_sys_reg_{get,set}_reg()
  KVM: arm64: Get rid of find_reg_by_id()
  KVM: arm64: vgic: Tidy-up calls to vgic_{get,set}_common_attr()
  KVM: arm64: vgic: Consolidate userspace access for base address setting
  KVM: arm64: vgic-v2: Add helper for legacy dist/cpuif base address setting
  KVM: arm64: vgic: Use {get,put}_user() instead of copy_{from.to}_user
  KVM: arm64: vgic-v2: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic-v3: Consolidate userspace access for MMIO registers
  KVM: arm64: vgic-v3: Use u32 to manage the line level from userspace
  KVM: arm64: vgic-v3: Convert userspace accessors over to FIELD_GET/FIELD_PREP
  KVM: arm64: vgic-v3: Make the userspace accessors use sysreg API
  KVM: arm64: vgic-v3: Push user access into vgic_v3_cpu_sysregs_uaccess()
  KVM: arm64: vgic-v3: Simplify vgic_v3_has_cpu_sysregs_attr()
  KVM: arm64: Get rid of reg_from/to_user()
  KVM: arm64: Consolidate sysreg userspace accesses
  KVM: arm64: Rely on index_to_param() for size checks on userspace access
  KVM: arm64: Introduce generic get_user/set_user helpers for system registers
  KVM: arm64: Reorder handling of invariant sysregs from userspace
  KVM: arm64: Add get_reg_by_id() as a sys_reg_desc retrieving helper

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