On 5/23/25 6:31 AM, Radim Krčmář wrote:
2025-05-22T12:03:43-07:00, Atish Patra <atishp@xxxxxxxxxxxx>:
Upgrade the SBI version to v3.0 so that corresponding features
can be enabled in the guest.
Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
---
diff --git a/arch/riscv/include/asm/kvm_vcpu_sbi.h b/arch/riscv/include/asm/kvm_vcpu_sbi.h
-#define KVM_SBI_VERSION_MAJOR 2
+#define KVM_SBI_VERSION_MAJOR 3
I think it's time to add versioning to KVM SBI implementation.
Userspace should be able to select the desired SBI version and KVM would
tell the guest that newer features are not supported.
We can achieve that through onereg interface by disabling individual SBI
extensions.
We can extend the existing onereg interface to disable a specific SBI
version directly
instead of individual ones to save those IOCTL as well.
We could somewhat get away with the userspace_sbi patch I posted,
because userspace would at least be in control of the SBI version, but
it would still be incorrect without a KVM enforcement, because a
misbehaving guest could use features that should not be supported.
