[PATCH v12 06/29] KVM: arm64: Handle FEAT_IDST for guest accesses to hidden registers

[Mark Brown]

In preparation for adding support for SMIDR_EL1 which is only available in
systems with SME factor out the FEAT_IDST injection from emulate-nested.c
into a helper and use it when handling hidden ID registers, ensuring that
we provide FEAT_IDST behaviour for them.

Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_emulate.h |  1 +
 arch/arm64/kvm/emulate-nested.c      |  6 +-----
 arch/arm64/kvm/inject_fault.c        | 15 +++++++++++++++
 arch/arm64/kvm/sys_regs.c            |  6 +++++-
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 5bf3d7e1d92c..994afbf479fc 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -45,6 +45,7 @@ bool kvm_condition_valid32(const struct kvm_vcpu *vcpu);
 void kvm_skip_instr32(struct kvm_vcpu *vcpu);
 
 void kvm_inject_undefined(struct kvm_vcpu *vcpu);
+void kvm_inject_undefined_idreg(struct kvm_vcpu *vcpu);
 void kvm_inject_sync(struct kvm_vcpu *vcpu, u64 esr);
 int kvm_inject_serror_esr(struct kvm_vcpu *vcpu, u64 esr);
 int kvm_inject_sea(struct kvm_vcpu *vcpu, bool iabt, u64 addr);
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index e688bc5139c1..f49b7b311d09 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2669,11 +2669,7 @@ bool triage_sysreg_trap(struct kvm_vcpu *vcpu, int *sr_index)
 		 * helper for the purpose of dealing with FEAT_IDST.
 		 */
 		if (in_feat_id_space(&params)) {
-			if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR2_EL1, IDS, IMP))
-				kvm_inject_sync(vcpu, kvm_vcpu_get_esr(vcpu));
-			else
-				kvm_inject_undefined(vcpu);
-
+			kvm_inject_undefined_idreg(vcpu);
 			return true;
 		}
 
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 89982bd3345f..e2f519ca3045 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -331,6 +331,21 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 		inject_undef64(vcpu);
 }
 
+/**
+ * kvm_inject_undefined_idreg - emulate UnimplementedIDRegister() pseudocode
+ * @vcpu: The vCPU in which to inject the exception
+ *
+ * It is assumed that this code is called from the VCPU thread and that the
+ * VCPU therefore is not currently executing guest code.
+ */
+void kvm_inject_undefined_idreg(struct kvm_vcpu *vcpu)
+{
+	if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR2_EL1, IDS, IMP))
+		kvm_inject_sync(vcpu, kvm_vcpu_get_esr(vcpu));
+	else
+		kvm_inject_undefined(vcpu);
+}
+
 static bool serror_is_masked(struct kvm_vcpu *vcpu)
 {
 	return (*vcpu_cpsr(vcpu) & PSR_A_BIT) && !effective_sctlr2_nmea(vcpu);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 5d5c579d4579..b352cd323e30 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4759,7 +4759,11 @@ static void perform_access(struct kvm_vcpu *vcpu,
 
 	/* Check for regs disabled by runtime config */
 	if (sysreg_hidden(vcpu, r)) {
-		kvm_inject_undefined(vcpu);
+		if (in_feat_id_space(params)) {
+			kvm_inject_undefined_idreg(vcpu);
+		} else {
+			kvm_inject_undefined(vcpu);
+		}
 		return;
 	}
 

-- 
2.47.3