It recently appeared that the nasty hack we use to call a HYP function on a non-VHE system has an interesting side effect on VHE: We wrap any such call into a hypercall, losing any form of type checking between the caller and the callee. This isn't a big deal if you can guarantee to write code that is always 100% correct, but it appears that I'm not you. In order to restore some sanity, let's use the following property: On a VHE system, it is always possible to call any function directly as they live in the same address space. We can thus always emit a direct call, and use a static key to flip from one to the other. As a bonus, this also sanitizes !VHE systems as we always generate code for noth revisions of the architecture. Marc Zyngier (3): arm/arm64: KVM: Introduce kvm_call_hyp_ret() arm64: KVM: Allow for direct call of HYP functions when using VHE arm64: KVM: Drop VHE-specific HYP call stub arch/arm/include/asm/kvm_host.h | 3 +++ arch/arm64/include/asm/kvm_host.h | 31 ++++++++++++++++++++++++++++++- arch/arm64/kvm/debug.c | 2 +- arch/arm64/kvm/hyp.S | 3 --- arch/arm64/kvm/hyp/hyp-entry.S | 12 ------------ virt/kvm/arm/arm.c | 2 +- virt/kvm/arm/vgic/vgic-v3.c | 4 ++-- 7 files changed, 37 insertions(+), 20 deletions(-) -- 2.20.1
