KVM: arm64: nv: Expose up to FEAT_Debugv8p8 to NV-enabled VMs

The changes to the debug architecture up to v8.8 are concerned with
external debug, which of course has no direct impact on VMs. Raise the
feature limit and document what's preventing us from raising it further.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index 65b5fbb88510031c2d546d87dde3529438a29538..74bd5140c9a4d0a83de86c8b46c774b39a8fec72 100644 (file)
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -1581,8 +1581,11 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val)
                         ID_AA64DFR0_EL1_PMSS           |
                         ID_AA64DFR0_EL1_TraceVer);
 
-               /* Cap Debug to ARMv8.1 */
-               val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, VHE);
+               /*
+                * FEAT_Debugv8p9 requires support for extended breakpoints /
+                * watchpoints.
+                */
+               val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64DFR0_EL1, DebugVer, V8P8);
                break;
        }