KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation

When handling a TLBI VA* instruction that potentially targets a
VNCR page mapping, we fail to mask out the top bits that contain
the ASID and TTL fields, hence potentially failing the VA check
in the TLB code.

An additional wrinkle is that we fail to sign extend the VA,
again leading to failed VA checks.

Fix both in one go by sign-extending the VA from bit 48, making
it comparable to the way we interpret VNCR_EL2.BADDR.

Fixes: 4ffa72a ("KVM: arm64: nv: Add S1 TLB invalidation primitive for VNCR_EL2")
Link: https://lore.kernel.org/r/20250525175759.780891-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

arch/arm64/kvm/nested.c

@@ -918,6 +918,8 @@ static void invalidate_vncr_va(struct kvm *kvm,
 	}
 }
 
+#define tlbi_va_s1_to_va(v)	(u64)sign_extend64((v) << 12, 48)
+
 static void compute_s1_tlbi_range(struct kvm_vcpu *vcpu, u32 inst, u64 val,
 				  struct s1e2_tlbi_scope *scope)
 {
@@ -964,7 +966,7 @@ static void compute_s1_tlbi_range(struct kvm_vcpu *vcpu, u32 inst, u64 val,
 		scope->size = ttl_to_size(FIELD_GET(TLBI_TTL_MASK, val));
 		if (!scope->size)
 			scope->size = SZ_1G;
-		scope->va = (val << 12) & ~(scope->size - 1);
+		scope->va = tlbi_va_s1_to_va(val) & ~(scope->size - 1);
 		scope->asid = FIELD_GET(TLBIR_ASID_MASK, val);
 		break;
 	case OP_TLBI_ASIDE1:
@@ -992,7 +994,7 @@ static void compute_s1_tlbi_range(struct kvm_vcpu *vcpu, u32 inst, u64 val,
 		scope->size = ttl_to_size(FIELD_GET(TLBI_TTL_MASK, val));
 		if (!scope->size)
 			scope->size = SZ_1G;
-		scope->va = (val << 12) & ~(scope->size - 1);
+		scope->va = tlbi_va_s1_to_va(val) & ~(scope->size - 1);
 		break;
 	case OP_TLBI_RVAE2:
 	case OP_TLBI_RVAE2IS: