[RFC PATCH 0/2] Add virtual SDEI support for arm64

[Heyi Guo]

As promised, this is the first RFC patch set for arm64 virtual SDEI
support.

New kvm capability KVM_CAP_FORWARD_HYPERCALL is added to probe if kvm
supports forwarding hypercalls, and the capability should be enabled
explicitly. PSCI can be set as exception for backward compatibility.

We reuse the existing term "hypercall" for SMC/HVC, as well as the
hypercall structure in kvm_run to exchange arguments and return
values. The definition on arm64 is as below:

exit_reason: KVM_EXIT_HYPERCALL

Input:
  nr: the immediate value of SMC/HVC calls; not really used today.
  args[6]: x0..x5 (This is not fully conform with SMCCC which requires
           x6 as argument as well, but use space can use GET_ONE_REG
           ioctl for such rare case).

Return:
  args[0..3]: x0..x3 as defined in SMCCC. We need to extract
              args[0..3] and write them to x0..x3 when hypercall exit
              returns.

And there is a corresponding patch set for qemu.

Please give your comments and suggestions.

Thanks,
HG

Cc: Peter Maydell <peter.maydell@xxxxxxxxxx>
Cc: Dave Martin <Dave.Martin@xxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>

Heyi Guo (2):
  kvm/arm: add capability to forward hypercall to user space
  kvm/arm64: expose hypercall_forwarding capability

 arch/arm/include/asm/kvm_host.h   |  5 +++++
 arch/arm64/include/asm/kvm_host.h |  5 +++++
 arch/arm64/kvm/reset.c            | 25 +++++++++++++++++++++++++
 include/kvm/arm_psci.h            |  1 +
 include/uapi/linux/kvm.h          |  3 +++
 virt/kvm/arm/arm.c                |  2 ++
 virt/kvm/arm/psci.c               | 30 ++++++++++++++++++++++++++++--
 7 files changed, 69 insertions(+), 2 deletions(-)

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1.8.3.1