KVM: arm64: Allow use of S1 PTW for non-NV vcpus

As we are about to use the S1 PTW in non-NV contexts, we must make
sure that we don't evaluate the EL2 state when dealing with the EL1&0
translation regime.

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

1 files changed, 28 insertions, 30 deletions

diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index 7b9711021db0..9baa929c102f 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -98,21 +98,26 @@ static enum trans_regime compute_translation_regime(struct kvm_vcpu *vcpu, u32 o
 	}
 }
 
+static u64 effective_tcr2(struct kvm_vcpu *vcpu, enum trans_regime regime)
+{
+	if (regime == TR_EL10) {
+		if (vcpu_has_nv(vcpu) &&
+		    !(__vcpu_sys_reg(vcpu, HCRX_EL2) & HCRX_EL2_TCR2En))
+			return 0;
+
+		return __vcpu_sys_reg(vcpu, TCR2_EL1);
+	}
+
+	return vcpu_read_sys_reg(vcpu, TCR2_EL2);
+}
+
 static bool s1pie_enabled(struct kvm_vcpu *vcpu, enum trans_regime regime)
 {
 	if (!kvm_has_s1pie(vcpu->kvm))
 		return false;
 
-	switch (regime) {
-	case TR_EL2:
-	case TR_EL20:
-		return vcpu_read_sys_reg(vcpu, TCR2_EL2) & TCR2_EL2_PIE;
-	case TR_EL10:
-		return  (__vcpu_sys_reg(vcpu, HCRX_EL2) & HCRX_EL2_TCR2En) &&
-			(__vcpu_sys_reg(vcpu, TCR2_EL1) & TCR2_EL1_PIE);
-	default:
-		BUG();
-	}
+	/* Abuse TCR2_EL1_PIE and use it for EL2 as well */
+	return effective_tcr2(vcpu, regime) & TCR2_EL1_PIE;
 }
 
 static void compute_s1poe(struct kvm_vcpu *vcpu, struct s1_walk_info *wi)
@@ -124,23 +129,11 @@ static void compute_s1poe(struct kvm_vcpu *vcpu, struct s1_walk_info *wi)
 		return;
 	}
 
-	switch (wi->regime) {
-	case TR_EL2:
-	case TR_EL20:
-		val = vcpu_read_sys_reg(vcpu, TCR2_EL2);
-		wi->poe = val & TCR2_EL2_POE;
-		wi->e0poe = (wi->regime == TR_EL20) && (val & TCR2_EL2_E0POE);
-		break;
-	case TR_EL10:
-		if (__vcpu_sys_reg(vcpu, HCRX_EL2) & HCRX_EL2_TCR2En) {
-			wi->poe = wi->e0poe = false;
-			return;
-		}
+	val = effective_tcr2(vcpu, wi->regime);
 
-		val = __vcpu_sys_reg(vcpu, TCR2_EL1);
-		wi->poe = val & TCR2_EL1_POE;
-		wi->e0poe = val & TCR2_EL1_E0POE;
-	}
+	/* Abuse TCR2_EL1_* for EL2 */
+	wi->poe = val & TCR2_EL1_POE;
+	wi->e0poe = (wi->regime != TR_EL2) && (val & TCR2_EL1_E0POE);
 }
 
 static int setup_s1_walk(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
@@ -150,11 +143,16 @@ static int setup_s1_walk(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
 	unsigned int stride, x;
 	bool va55, tbi, lva;
 
-	hcr = __vcpu_sys_reg(vcpu, HCR_EL2);
-
 	va55 = va & BIT(55);
 
-	wi->s2 = wi->regime == TR_EL10 && (hcr & (HCR_VM | HCR_DC));
+	if (vcpu_has_nv(vcpu)) {
+		hcr = __vcpu_sys_reg(vcpu, HCR_EL2);
+		wi->s2 = wi->regime == TR_EL10 && (hcr & (HCR_VM | HCR_DC));
+	} else {
+		WARN_ON_ONCE(wi->regime != TR_EL10);
+		wi->s2 = false;
+		hcr = 0;
+	}
 
 	switch (wi->regime) {
 	case TR_EL10:
@@ -851,7 +849,7 @@ static u64 compute_par_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
 		par  = SYS_PAR_EL1_NSE;
 		par |= wr->pa & SYS_PAR_EL1_PA;
 
-		if (wi->regime == TR_EL10 &&
+		if (wi->regime == TR_EL10 && vcpu_has_nv(vcpu) &&
 		    (__vcpu_sys_reg(vcpu, HCR_EL2) & HCR_DC)) {
 			par |= FIELD_PREP(SYS_PAR_EL1_ATTR,
 					  MEMATTR(WbRaWa, WbRaWa));