[v2,00/20] Introduce separate nVHE hyp context

Message

Andrew Scull Aug. 20, 2020, 10:34 a.m. UTC

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 for hyp visiting these topics on the way:

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

After four small refactors, focus turns to adding a new exception vector
for the nVHE hyp to use with the host. With this new freedom, the
erroneous consumption of the host's RAS errors by nVHE is corrected.

Following this, attention turns to fixing hyp panics from the guest
context, e.g. an invalid vector, so they have a chance of completely
cleanly with features such as shadow call stack (SCS) enabled on VHE.

Then, 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.

This series is based on v5.8-rc1 and has been tested on a VIM 3L.

From v1:
 - https://lore.kernel.org/kvmarm/[e-mail]/
 - 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
   introduced.

Cc: Marc Zyngier <[e-mail]>
Cc: James Morse <[e-mail]>
Cc: Suzuki Poulose <[e-mail]>
Cc: Sudeep Holla <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]

Andrew Scull (20):
  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: Preserve host DISR_EL1
  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
  KVM: arm64: nVHE: Handle stub HVCs in the host loop

 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             |  83 +---------
 arch/arm64/kvm/hyp/include/hyp/switch.h    |   9 +-
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h |  16 +-
 arch/arm64/kvm/hyp/nvhe/Makefile           |   2 +-
 arch/arm64/kvm/hyp/nvhe/host.S             | 156 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/hyp-init.S         |  80 ++++++----
 arch/arm64/kvm/hyp/nvhe/hyp-main.c         | 171 +++++++++++++++++++++
 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 +--
 21 files changed, 606 insertions(+), 278 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