[PATCH v3 32/66] KVM: arm64: nv: Hide RAS from nested guests

[Marc Zyngier]

We don't want to expose complicated features to guests until we have
a good grasp on the basic CPU emulation. So let's pretend that RAS,
doesn't exist in a nested guest. We already hide the feature bits,
let's now make sure VDISR_EL1 will UNDEF.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d011b8156c52..090ce14306ba 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -527,6 +527,14 @@ static bool trap_raz_wi(struct kvm_vcpu *vcpu,
 		return read_zero(vcpu, p);
 }
 
+static bool trap_undef(struct kvm_vcpu *vcpu,
+		       struct sys_reg_params *p,
+		       const struct sys_reg_desc *r)
+{
+	kvm_inject_undefined(vcpu);
+	return false;
+}
+
 /*
  * ARMv8.1 mandates at least a trivial LORegion implementation, where all the
  * RW registers are RES0 (which we can implement as RAZ/WI). On an ARMv8.0
@@ -2083,6 +2091,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_VBAR_EL2), access_rw, reset_val, VBAR_EL2, 0 },
 	{ SYS_DESC(SYS_RVBAR_EL2), access_rw, reset_val, RVBAR_EL2, 0 },
 	{ SYS_DESC(SYS_RMR_EL2), access_wi, reset_val, RMR_EL2, 1 },
+	{ SYS_DESC(SYS_VDISR_EL2), trap_undef },
 
 	{ SYS_DESC(SYS_CONTEXTIDR_EL2), access_rw, reset_val, CONTEXTIDR_EL2, 0 },
 	{ SYS_DESC(SYS_TPIDR_EL2), access_rw, reset_val, TPIDR_EL2, 0 },
-- 
2.29.2