diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2023-04-04 15:40:45 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-04-05 12:07:41 +0100 |
| commit | d824dff1919bbd523d4d5c860437d043c0ad121d (patch) | |
| tree | 0ea664fd97f3afdb2edd9bb787b7d79161530535 /arch/arm64/kvm/hypercalls.c | |
| parent | fb88707dd39bd1d5ec4a058776de9ee99bcc7b72 (diff) | |
KVM: arm64: Add support for KVM_EXIT_HYPERCALL
In anticipation of user hypercall filters, add the necessary plumbing to
get SMCCC calls out to userspace. Even though the exit structure has
space for KVM to pass register arguments, let's just avoid it altogether
and let userspace poke at the registers via KVM_GET_ONE_REG.
This deliberately stretches the definition of a 'hypercall' to cover
SMCs from EL1 in addition to the HVCs we know and love. KVM doesn't
support EL1 calls into secure services, but now we can paint that as a
userspace problem and be done with it.
Finally, we need a flag to let userspace know what conduit instruction
was used (i.e. SMC vs. HVC).
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230404154050.2270077-9-oliver.upton@linux.dev
Diffstat (limited to 'arch/arm64/kvm/hypercalls.c')
| -rw-r--r-- | arch/arm64/kvm/hypercalls.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index ba7cd84c6668..2db53709bec1 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -180,6 +180,19 @@ static u8 kvm_smccc_get_action(struct kvm_vcpu *vcpu, u32 func_id) return KVM_SMCCC_FILTER_DENY; } +static void kvm_prepare_hypercall_exit(struct kvm_vcpu *vcpu, u32 func_id) +{ + u8 ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu)); + struct kvm_run *run = vcpu->run; + + run->exit_reason = KVM_EXIT_HYPERCALL; + run->hypercall.nr = func_id; + run->hypercall.flags = 0; + + if (ec == ESR_ELx_EC_SMC32 || ec == ESR_ELx_EC_SMC64) + run->hypercall.flags |= KVM_HYPERCALL_EXIT_SMC; +} + int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) { struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat; @@ -195,6 +208,9 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu) break; case KVM_SMCCC_FILTER_DENY: goto out; + case KVM_SMCCC_FILTER_FWD_TO_USER: + kvm_prepare_hypercall_exit(vcpu, func_id); + return 0; default: WARN_RATELIMIT(1, "Unhandled SMCCC filter action: %d\n", action); goto out; |