arm64: KVM: vgic-v2: Add GICV access from HYP

Now that we have the necessary infrastructure to handle MMIO accesses in HYP, perform the GICV access on behalf of the guest. This requires checking that the access is strictly 32bit, properly aligned, and falls within the expected range. When all condition are satisfied, we perform the access and tell the rest of the HYP code that the instruction has been correctly emulated. Reviewed-by: Christoffer Dall <[email protected]> Signed-off-by: Marc Zyngier <[email protected]> Signed-off-by: Christoffer Dall <[email protected]>
ambv · Sep 8, 2016 · bf8feb3 · bf8feb3
1 parent fb5ee36
commit bf8feb3
Show file tree

Hide file tree

Showing 2 changed files with 42 additions and 0 deletions.
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
@@ -50,6 +50,9 @@ struct vgic_global {
 	/* Physical address of vgic virtual cpu interface */
 	phys_addr_t		vcpu_base;
 
+	/* GICV mapping */
+	void __iomem		*vcpu_base_va;
+
 	/* virtual control interface mapping */
 	void __iomem		*vctrl_base;
 

diff --git a/virt/kvm/arm/hyp/vgic-v2-sr.c b/virt/kvm/arm/hyp/vgic-v2-sr.c
@@ -19,6 +19,7 @@
 #include <linux/irqchip/arm-gic.h>
 #include <linux/kvm_host.h>
 
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 
 static void __hyp_text save_maint_int_state(struct kvm_vcpu *vcpu,
@@ -171,6 +172,44 @@ void __hyp_text __vgic_v2_restore_state(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_ARM64
 bool __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu)
 {
+	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
+	struct vgic_dist *vgic = &kvm->arch.vgic;
+	phys_addr_t fault_ipa;
+	void __iomem *addr;
+	int rd;
+
+	/* Build the full address */
+	fault_ipa  = kvm_vcpu_get_fault_ipa(vcpu);
+	fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
+
+	/* If not for GICV, move on */
+	if (fault_ipa <  vgic->vgic_cpu_base ||
+	    fault_ipa >= (vgic->vgic_cpu_base + KVM_VGIC_V2_CPU_SIZE))
 		return false;
+
+	/* Reject anything but a 32bit access */
+	if (kvm_vcpu_dabt_get_as(vcpu) != sizeof(u32))
+		return false;
+
+	/* Not aligned? Don't bother */
+	if (fault_ipa & 3)
+		return false;
+
+	rd = kvm_vcpu_dabt_get_rd(vcpu);
+	addr  = kern_hyp_va((kern_hyp_va(&kvm_vgic_global_state))->vcpu_base_va);
+	addr += fault_ipa - vgic->vgic_cpu_base;
+
+	if (kvm_vcpu_dabt_iswrite(vcpu)) {
+		u32 data = vcpu_data_guest_to_host(vcpu,
+						   vcpu_get_reg(vcpu, rd),
+						   sizeof(u32));
+		writel_relaxed(data, addr);
+	} else {
+		u32 data = readl_relaxed(addr);
+		vcpu_set_reg(vcpu, rd, vcpu_data_host_to_guest(vcpu, data,
+							       sizeof(u32)));
+	}
+
+	return true;
 }
 #endif