arm: KVM: Make unexpected register accesses inject an undef
Reads from write-only system registers are generally confined to
EL1 and not propagated to EL2 (that's what the architecture
mantates). In order to be sure that we have a sane behaviour
even in the unlikely event that we have a broken system, we still
handle it in KVM. Same goes for write to RO registers.
In that case, let's inject an undef into the guest.
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index 3e5e419..519aac1 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -40,6 +40,24 @@
* Co-processor emulation
*****************************************************************************/
+static bool write_to_read_only(struct kvm_vcpu *vcpu,
+ const struct coproc_params *params)
+{
+ WARN_ONCE(1, "CP15 write to read-only register\n");
+ print_cp_instr(params);
+ kvm_inject_undefined(vcpu);
+ return false;
+}
+
+static bool read_from_write_only(struct kvm_vcpu *vcpu,
+ const struct coproc_params *params)
+{
+ WARN_ONCE(1, "CP15 read to write-only register\n");
+ print_cp_instr(params);
+ kvm_inject_undefined(vcpu);
+ return false;
+}
+
/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
static u32 cache_levels;