libhyp: Detect non-protected through MMIO_GUARD
To distinguish between protected and non-protected, we issue a MEM_SHARE
HVC assuming that it is only supported in pVMs. This works for Android
kernels based on 5.10 but breaks in 5.15 and 6.1 because the kernel now
supports the HVC, even for non-protected VMs. Instead, rely on a similar
HVC for MMIO_GUARD, assumed to never be supported for non-protected VMs.
Bug: 290380929
Test: atest rialto_test # On a device running 5.15
Change-Id: Ia4dc9e72025a34cbc4edfdf3f0acd4e78f3f3bd0
diff --git a/libs/hyp/src/hypervisor/mod.rs b/libs/hyp/src/hypervisor/mod.rs
index bc9e406..309f967 100644
--- a/libs/hyp/src/hypervisor/mod.rs
+++ b/libs/hyp/src/hypervisor/mod.rs
@@ -60,8 +60,10 @@
GeniezoneHypervisor::UUID => Ok(HypervisorBackend::Geniezone),
GunyahHypervisor::UUID => Ok(HypervisorBackend::Gunyah),
RegularKvmHypervisor::UUID => {
- // Protected KVM has the same UUID so differentiate based on MEM_SHARE.
- match ProtectedKvmHypervisor.as_mem_sharer().unwrap().granule() {
+ // Protected KVM has the same UUID as "regular" KVM so issue an HVC that is assumed
+ // to only be supported by pKVM: if it returns SUCCESS, deduce that this is pKVM
+ // and if it returns NOT_SUPPORTED assume that it is "regular" KVM.
+ match ProtectedKvmHypervisor.as_mmio_guard().unwrap().granule() {
Ok(_) => Ok(HypervisorBackend::ProtectedKvm),
Err(Error::KvmError(KvmError::NotSupported, _)) => {
Ok(HypervisorBackend::RegularKvm)
@@ -101,7 +103,7 @@
}
fn detect_hypervisor() -> HypervisorBackend {
- query_vendor_hyp_call_uid().try_into().expect("Unknown hypervisor")
+ query_vendor_hyp_call_uid().try_into().expect("Failed to detect hypervisor")
}
/// Gets the hypervisor singleton.