From: Jintack Lim <jintack.lim@xxxxxxxxxx>
Forward the EL1 virtual memory register traps to the virtual EL2 if they
are not coming from the virtual EL2 and the virtual HCR_EL2.TVM or TRVM
bit is set.
This is for recursive nested virtualization.
Signed-off-by: Jintack Lim <jintack.lim@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 582d62aa48b7..0f74b9277a86 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -436,6 +436,27 @@ static bool access_dcsw(struct kvm_vcpu *vcpu,
return true;
}
+/* This function is to support the recursive nested virtualization */
+static bool forward_vm_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
+{
+ u64 hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+
+ /* If a trap comes from the virtual EL2, the host hypervisor handles. */
+ if (vcpu_mode_el2(vcpu))
+ return false;
+
+ /*
+ * If the virtual HCR_EL2.TVM or TRVM bit is set, we need to foward
+ * this trap to the virtual EL2.
+ */
+ if ((hcr_el2 & HCR_TVM) && p->is_write)
+ return true;
+ else if ((hcr_el2 & HCR_TRVM) && !p->is_write)
+ return true;
+
+ return false;
+}
+
/*
* Generic accessor for VM registers. Only called as long as HCR_TVM
* is set. If the guest enables the MMU, we stop trapping the VM
@@ -452,6 +473,9 @@ 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));
+
BUG_ON(!vcpu_mode_el2(vcpu) && !p->is_write);
if (!p->is_write) {
--
2.20.1
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