[PATCH v3 00/18] Introduce separate nVHE hyp context

Andrew Scull ascull at google.com
Thu Sep 3 09:52:49 EDT 2020

As a step on the way to isolating hyp from the host on nVHE as part of
Android's "Protected KVM" project, this series introduces a separate
register context. Topic include:

 - RAS for nVHE
 - Panicking from guest vectors with SCS
 - Switching to hyp context
 - Migration hyp interface off of function pointers

First 4 patches are small refactors. Then an exception vector is added
just for the nVHE host to untangle the existing EL2 vector e.g. to
separate the RAS cases.

Hyp panics from the guest context, e.g. from an invalid vector, are
fixed so they have a chance of completely cleanly with features that
depend on register state such as x18 for shadow call stack (SCS) enabled
on VHE.

Finally, hyp is made to switch to its own context rather than borrowing the
host context before migrating the hyp interface from raw function
pointers to SMCCC based functions IDs.

>From v2:
 - https://lore.kernel.org/kvmarm/20200820103446.959000-1-ascull@google.com/
 - Rebased onto 5.9-rc3.
 - Removed some of the unused separation of host and hyp.

>From v1:
 - https://lore.kernel.org/kvmarm/20200715184438.1390996-1-ascull@google.com/
 - HVC microbenchmark overhead cut from over 15% to under 6%.
 - Abandon the symmetry of a run loop in hyp and treating the host as a
   vCPU as there was little practical benefit for the overhead it

Cc: Marc Zyngier <maz at kernel.org>
Cc: James Morse <james.morse at arm.com>
Cc: Suzuki Poulose <suzuki.poulose at arm.com>
Cc: Sudeep Holla <sudeep.holla at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: kernel-team at android.com
Cc: kvmarm at lists.cs.columbia.edu
Cc: linux-arm-kernel at lists.infradead.org

Andrew Scull (18):
  KVM: arm64: Remove __activate_vm wrapper
  KVM: arm64: Remove hyp_panic arguments
  KVM: arm64: Remove kvm_host_data_t typedef
  KVM: arm64: Restrict symbol aliasing to outside nVHE
  KVM: arm64: Save chosen hyp vector to a percpu variable
  KVM: arm64: nVHE: Use separate vector for the host
  KVM: arm64: nVHE: Don't consume host SErrors with ESB
  KVM: arm64: Introduce hyp context
  KVM: arm64: Update context references from host to hyp
  KVM: arm64: Restore hyp when panicking in guest context
  KVM: arm64: Share context save and restore macros
  KVM: arm64: nVHE: Switch to hyp context for EL2
  KVM: arm64: nVHE: Handle hyp panics
  smccc: Cast arguments to unsigned long
  KVM: arm64: nVHE: Pass pointers consistently to hyp-init
  KVM: arm64: nVHE: Migrate hyp interface to SMCCC
  KVM: arm64: nVHE: Migrate hyp-init to SMCCC
  KVM: arm64: nVHE: Fix pointers during SMCCC convertion

 arch/arm64/include/asm/kvm_asm.h        |  78 ++++++++++
 arch/arm64/include/asm/kvm_host.h       |  26 ++--
 arch/arm64/include/asm/kvm_hyp.h        |   9 +-
 arch/arm64/include/asm/kvm_ptrauth.h    |   6 +-
 arch/arm64/kernel/image-vars.h          |   2 +
 arch/arm64/kvm/Makefile                 |   2 +-
 arch/arm64/kvm/arm.c                    |  34 ++++-
 arch/arm64/kvm/hyp.S                    |  34 -----
 arch/arm64/kvm/hyp/entry.S              |  95 ++++++-------
 arch/arm64/kvm/hyp/hyp-entry.S          |  76 +---------
 arch/arm64/kvm/hyp/include/hyp/switch.h |  15 +-
 arch/arm64/kvm/hyp/nvhe/Makefile        |   2 +-
 arch/arm64/kvm/hyp/nvhe/host.S          | 180 ++++++++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/hyp-init.S      |  67 +++++----
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      | 122 ++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/switch.c        |  37 +++--
 arch/arm64/kvm/hyp/nvhe/tlb.c           |   2 -
 arch/arm64/kvm/hyp/vhe/switch.c         |  18 +--
 arch/arm64/kvm/vgic/vgic-v3.c           |   4 +-
 include/linux/arm-smccc.h               |  20 +--
 20 files changed, 558 insertions(+), 271 deletions(-)
 delete mode 100644 arch/arm64/kvm/hyp.S
 create mode 100644 arch/arm64/kvm/hyp/nvhe/host.S
 create mode 100644 arch/arm64/kvm/hyp/nvhe/hyp-main.c


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