[PATCH 28/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting

[Marc Zyngier <marc.zyngier@xxxxxxx>]

From: Jintack Lim <jintack@xxxxxxxxxxxxxxx>

Forward ELR_EL1, SPSR_EL1 and VBAR_EL1 traps to the virtual EL2 if the
virtual HCR_EL2.NV bit is set.

This is for recursive nested virtualization.

Signed-off-by: Jintack Lim <jintack@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
 arch/arm64/include/asm/kvm_arm.h |  1 +
 arch/arm64/kvm/sys_regs.c        | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index d21486274eeb..55f4525c112c 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -24,6 +24,7 @@
 
 /* Hyp Configuration Register (HCR) bits */
 #define HCR_FWB		(UL(1) << 46)
+#define HCR_NV1		(UL(1) << 43)
 #define HCR_NV		(UL(1) << 42)
 #define HCR_API		(UL(1) << 41)
 #define HCR_APK		(UL(1) << 40)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0f74b9277a86..beadebcfc888 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -473,8 +473,10 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	if (el12_reg(p) && forward_nv_traps(vcpu))
 		return false;
 
-	if (!el12_reg(p) && forward_vm_traps(vcpu, p))
-		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+	if (!el12_reg(p) && forward_vm_traps(vcpu, p)) {
+		kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+		return false;
+	}
 
 	BUG_ON(!vcpu_mode_el2(vcpu) && !p->is_write);
 
@@ -1643,6 +1645,13 @@ static bool access_sp_el1(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+
+/* This function is to support the recursive nested virtualization */
+static bool forward_nv1_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
+{
+	return forward_traps(vcpu, HCR_NV1);
+}
+
 static bool access_elr(struct kvm_vcpu *vcpu,
 		       struct sys_reg_params *p,
 		       const struct sys_reg_desc *r)
@@ -1650,6 +1659,9 @@ static bool access_elr(struct kvm_vcpu *vcpu,
 	if (el12_reg(p) && forward_nv_traps(vcpu))
 		return false;
 
+	if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+		return false;
+
 	if (p->is_write)
 		vcpu->arch.ctxt.gp_regs.elr_el1 = p->regval;
 	else
@@ -1665,6 +1677,9 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
 	if (el12_reg(p) && forward_nv_traps(vcpu))
 		return false;
 
+	if (!el12_reg(p) && forward_nv1_traps(vcpu, p))
+		return false;
+
 	if (p->is_write)
 		vcpu->arch.ctxt.gp_regs.spsr[KVM_SPSR_EL1] = p->regval;
 	else
-- 
2.20.1