[PATCH v6 00/13] arm64/KVM: RAS & IESB for firmware first support

[James Morse]

Hello,

The aim of this series is to enable IESB to let us kick any pending RAS
errors into firmware to be handled by firmware-first.

v6 is a rebase onto arm64's for-next/core branch to fix the conflicts.

I've picked up the Reviewed-by's from v4 that I missed on patches 7, 9 and 13,
(they have the relevant patchwork links). Please call me names if I missed any
more! (Dropped on patches 11 & 12 is deliberate due to handle_exit_early())


Not all systems will have firmware support, so these RAS errors will become
pending SErrors delivered to the kernel. The first part of the series adds
some crude categorization for SErrors into 'fatal' or ignorable. This stops us
panic()ing for corrected errors, but we make no attempt to handle the error.
Proper kernel-first support will be able to do a much better job here.

The second part of the series provides the same minimal handling for SError
that interrupt KVM. KVM is currently unable to handle SErrors during
world-switch, unless they occur during a magic single-instruction window,
it hyp-panics. I suspect this will be easier to fix once the VHE world-switch
is further optimised.

KVMs kvm_inject_vabt() needs updating for v8.2 as now we can specify an ESR,
and all-zeros has a RAS meaning.

Until we have kernel-first support, containable RAS errors that interrupt a
guest are considered by KVM using the same crude categorization the arch code
uses. Fatal errors are treated as an impdef-SError, non-fatal errors are
ignored. Again, proper kernel-first support will do better.
(uncontained errors from a guest will always cause the host to panic)


Known issues:
 * Synchronous external abort SET severity is not yet considered, all
   synchronous-external-aborts are still considered fatal.

 * KVM-Migration: HCR_EL2.VSE and VSESR_EL2 cannot be migrated when the guest
   has an SError pending. An API using {G,S}ET_EVENTS is on my todo list.

 * KVM unmasks SError and IRQ before calling handle_exit_early, we may take
   interrupts while holding an uncontained ESR... (this is currently an
   improvement on assuming its an impdef error we can blame on the guest)
    * We need to fix this for APEI's SEI or kernel-first RAS, the guest-exit
      SError handling will need to move to before kvm_arm_vhe_guest_exit(),
      or at least into a region where SError and IRQ is still masked.

Thanks,

James


Dongjiu Geng (1):
  KVM: arm64: Emulate RAS error registers and set HCR_EL2's TERR & TEA

James Morse (11):
  arm64: cpufeature: __this_cpu_has_cap() shouldn't stop early
  arm64: sysreg: Move to use definitions for all the SCTLR bits
  arm64: kernel: Survive corrected RAS errors notified by SError
  arm64: Unconditionally enable IESB on exception entry/return for
    firmware-first
  arm64: kernel: Prepare for a DISR user
  KVM: arm/arm64: mask/unmask daif around VHE guests
  KVM: arm64: Set an impdef ESR for Virtual-SError using VSESR_EL2.
  KVM: arm64: Save/Restore guest DISR_EL1
  KVM: arm64: Save ESR_EL2 on guest SError
  KVM: arm64: Handle RAS SErrors from EL1 on guest exit
  KVM: arm64: Handle RAS SErrors from EL2 on guest exit

Xie XiuQi (1):
  arm64: cpufeature: Detect CPU RAS Extentions

 arch/arm/include/asm/kvm_host.h      |  5 +++
 arch/arm64/Kconfig                   | 16 +++++++
 arch/arm64/include/asm/assembler.h   |  7 ++++
 arch/arm64/include/asm/cpucaps.h     |  3 +-
 arch/arm64/include/asm/esr.h         | 20 +++++++++
 arch/arm64/include/asm/exception.h   | 14 +++++++
 arch/arm64/include/asm/kvm_arm.h     |  2 +
 arch/arm64/include/asm/kvm_emulate.h | 17 ++++++++
 arch/arm64/include/asm/kvm_host.h    | 17 ++++++++
 arch/arm64/include/asm/processor.h   |  1 +
 arch/arm64/include/asm/sysreg.h      | 81 +++++++++++++++++++++++++++++++++++-
 arch/arm64/include/asm/traps.h       | 54 ++++++++++++++++++++++++
 arch/arm64/kernel/asm-offsets.c      |  1 +
 arch/arm64/kernel/cpufeature.c       | 26 +++++++++++-
 arch/arm64/kernel/head.S             | 13 ++----
 arch/arm64/kernel/traps.c            | 51 ++++++++++++++++++++---
 arch/arm64/kvm/handle_exit.c         | 32 +++++++++++++-
 arch/arm64/kvm/hyp/entry.S           | 13 ++++++
 arch/arm64/kvm/hyp/switch.c          | 12 ++++--
 arch/arm64/kvm/hyp/sysreg-sr.c       |  6 +++
 arch/arm64/kvm/inject_fault.c        | 13 +++++-
 arch/arm64/kvm/sys_regs.c            | 11 +++++
 arch/arm64/mm/proc.S                 | 29 +++----------
 virt/kvm/arm/arm.c                   |  7 ++++
 24 files changed, 402 insertions(+), 49 deletions(-)

-- 
2.15.1