[RFC PATCH v2 35/38] KVM: arm64: Respect the virtual HCR_EL2.NV bit setting for EL12 register traps

[Jintack Lim]

In addition to EL2 register accesses, setting NV bit will also make EL12
register accesses trap to EL2. To emulate this for the virtual EL2,
forword traps due to EL12 register accessses 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.lim@xxxxxxxxxx>
---
 arch/arm64/kvm/sys_regs.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4fd7090..3559cf7 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -149,6 +149,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	int i;
 	const struct el1_el2_map *map;
 
+	if (el12_reg(p) && forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	/*
 	 * Redirect EL1 register accesses to the corresponding EL2 registers if
 	 * they are meant to access EL2 registers.
@@ -959,6 +962,9 @@ static bool access_cntkctl_el12(struct kvm_vcpu *vcpu,
 			 struct sys_reg_params *p,
 			 const struct sys_reg_desc *r)
 {
+	if (forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	access_rw(p, &vcpu_sys_reg(vcpu, r->reg));
 	return true;
 }
@@ -1005,6 +1011,9 @@ static bool access_elr(struct kvm_vcpu *vcpu,
 		struct sys_reg_params *p,
 		const struct sys_reg_desc *r)
 {
+	if (el12_reg(p) && forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	access_rw(p, &vcpu->arch.ctxt.gp_regs.elr_el1);
 	return true;
 }
@@ -1013,6 +1022,9 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
 		struct sys_reg_params *p,
 		const struct sys_reg_desc *r)
 {
+	if (el12_reg(p) && forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	access_rw(p, &vcpu->arch.ctxt.gp_regs.spsr[KVM_SPSR_EL1]);
 	return true;
 }
@@ -1021,6 +1033,9 @@ static bool access_vbar(struct kvm_vcpu *vcpu,
 		struct sys_reg_params *p,
 		const struct sys_reg_desc *r)
 {
+	if (el12_reg(p) && forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	access_rw(p, &vcpu_sys_reg(vcpu, r->reg));
 	return true;
 }
@@ -1031,6 +1046,9 @@ static bool access_cpacr(struct kvm_vcpu *vcpu,
 {
 	u64 reg = sys_reg(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
 
+	if (el12_reg(p) && forward_nv_traps(vcpu))
+		return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu));
+
 	/*
 	 * When the virtual HCR_EL2.E2H == 1, an access to CPACR_EL1
 	 * in the virtual EL2 is to access CPTR_EL2.
-- 
1.9.1