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(-) -- 1.8.3.1