3 files changed, 93 insertions, 53 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 571b64a01c50..8d1da1af4b09 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -360,29 +360,6 @@ static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
-static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
-					     struct vgic_its *its,
-					     gpa_t addr, unsigned int len)
-{
-	u32 reg = 0;
-
-	mutex_lock(&its->cmd_lock);
-	if (its->creadr == its->cwriter)
-		reg |= GITS_CTLR_QUIESCENT;
-	if (its->enabled)
-		reg |= GITS_CTLR_ENABLE;
-	mutex_unlock(&its->cmd_lock);
-
-	return reg;
-}
-
-static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
-				     gpa_t addr, unsigned int len,
-				     unsigned long val)
-{
-	its->enabled = !!(val & GITS_CTLR_ENABLE);
-}
-
 static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
 					      struct vgic_its *its,
 					      gpa_t addr, unsigned int len)
@@ -1161,33 +1138,16 @@ static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its,
 #define ITS_CMD_SIZE			32
 #define ITS_CMD_OFFSET(reg)		((reg) & GENMASK(19, 5))
 
-/*
- * By writing to CWRITER the guest announces new commands to be processed.
- * To avoid any races in the first place, we take the its_cmd lock, which
- * protects our ring buffer variables, so that there is only one user
- * per ITS handling commands at a given time.
- */
-static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
-					gpa_t addr, unsigned int len,
-					unsigned long val)
+/* Must be called with the cmd_lock held. */
+static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its)
 {
 	gpa_t cbaser;
 	u64 cmd_buf[4];
-	u32 reg;
 
-	if (!its)
-		return;
-
-	mutex_lock(&its->cmd_lock);
-
-	reg = update_64bit_reg(its->cwriter, addr & 7, len, val);
-	reg = ITS_CMD_OFFSET(reg);
-	if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
-		mutex_unlock(&its->cmd_lock);
+	/* Commands are only processed when the ITS is enabled. */
+	if (!its->enabled)
 		return;
-	}
 
-	its->cwriter = reg;
 	cbaser = CBASER_ADDRESS(its->cbaser);
 
 	while (its->cwriter != its->creadr) {
@@ -1207,6 +1167,34 @@ static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
 		if (its->creadr == ITS_CMD_BUFFER_SIZE(its->cbaser))
 			its->creadr = 0;
 	}
+}
+
+/*
+ * By writing to CWRITER the guest announces new commands to be processed.
+ * To avoid any races in the first place, we take the its_cmd lock, which
+ * protects our ring buffer variables, so that there is only one user
+ * per ITS handling commands at a given time.
+ */
+static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
+					gpa_t addr, unsigned int len,
+					unsigned long val)
+{
+	u64 reg;
+
+	if (!its)
+		return;
+
+	mutex_lock(&its->cmd_lock);
+
+	reg = update_64bit_reg(its->cwriter, addr & 7, len, val);
+	reg = ITS_CMD_OFFSET(reg);
+	if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
+		mutex_unlock(&its->cmd_lock);
+		return;
+	}
+	its->cwriter = reg;
+
+	vgic_its_process_commands(kvm, its);
 
 	mutex_unlock(&its->cmd_lock);
 }
@@ -1287,6 +1275,39 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm,
 	*regptr = reg;
 }
 
+static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
+					     struct vgic_its *its,
+					     gpa_t addr, unsigned int len)
+{
+	u32 reg = 0;
+
+	mutex_lock(&its->cmd_lock);
+	if (its->creadr == its->cwriter)
+		reg |= GITS_CTLR_QUIESCENT;
+	if (its->enabled)
+		reg |= GITS_CTLR_ENABLE;
+	mutex_unlock(&its->cmd_lock);
+
+	return reg;
+}
+
+static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
+				     gpa_t addr, unsigned int len,
+				     unsigned long val)
+{
+	mutex_lock(&its->cmd_lock);
+
+	its->enabled = !!(val & GITS_CTLR_ENABLE);
+
+	/*
+	 * Try to process any pending commands. This function bails out early
+	 * if the ITS is disabled or no commands have been queued.
+	 */
+	vgic_its_process_commands(kvm, its);
+
+	mutex_unlock(&its->cmd_lock);
+}
+
 #define REGISTER_ITS_DESC(off, rd, wr, length, acc)		\
 {								\
 	.reg_offset = off,					\
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 3654b4c835ef..2a5db1352722 100644
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -180,21 +180,37 @@ unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu,
 static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 				    bool new_active_state)
 {
+	struct kvm_vcpu *requester_vcpu;
 	spin_lock(&irq->irq_lock);
+
+	/*
+	 * The vcpu parameter here can mean multiple things depending on how
+	 * this function is called; when handling a trap from the kernel it
+	 * depends on the GIC version, and these functions are also called as
+	 * part of save/restore from userspace.
+	 *
+	 * Therefore, we have to figure out the requester in a reliable way.
+	 *
+	 * When accessing VGIC state from user space, the requester_vcpu is
+	 * NULL, which is fine, because we guarantee that no VCPUs are running
+	 * when accessing VGIC state from user space so irq->vcpu->cpu is
+	 * always -1.
+	 */
+	requester_vcpu = kvm_arm_get_running_vcpu();
+
 	/*
 	 * If this virtual IRQ was written into a list register, we
 	 * have to make sure the CPU that runs the VCPU thread has
-	 * synced back LR state to the struct vgic_irq.  We can only
-	 * know this for sure, when either this irq is not assigned to
-	 * anyone's AP list anymore, or the VCPU thread is not
-	 * running on any CPUs.
+	 * synced back the LR state to the struct vgic_irq.
 	 *
-	 * In the opposite case, we know the VCPU thread may be on its
-	 * way back from the guest and still has to sync back this
-	 * IRQ, so we release and re-acquire the spin_lock to let the
-	 * other thread sync back the IRQ.
+	 * As long as the conditions below are true, we know the VCPU thread
+	 * may be on its way back from the guest (we kicked the VCPU thread in
+	 * vgic_change_active_prepare)  and still has to sync back this IRQ,
+	 * so we release and re-acquire the spin_lock to let the other thread
+	 * sync back the IRQ.
 	 */
 	while (irq->vcpu && /* IRQ may have state in an LR somewhere */
+	       irq->vcpu != requester_vcpu && /* Current thread is not the VCPU thread */
 	       irq->vcpu->cpu != -1) /* VCPU thread is running */
 		cond_resched_lock(&irq->irq_lock);
 
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index edc6ee2dc852..be0f4c3e0142 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -229,10 +229,13 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu)
 	/*
 	 * If we are emulating a GICv3, we do it in an non-GICv2-compatible
 	 * way, so we force SRE to 1 to demonstrate this to the guest.
+	 * Also, we don't support any form of IRQ/FIQ bypass.
 	 * This goes with the spec allowing the value to be RAO/WI.
 	 */
 	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
-		vgic_v3->vgic_sre = ICC_SRE_EL1_SRE;
+		vgic_v3->vgic_sre = (ICC_SRE_EL1_DIB |
+				     ICC_SRE_EL1_DFB |
+				     ICC_SRE_EL1_SRE);
 		vcpu->arch.vgic_cpu.pendbaser = INITIAL_PENDBASER_VALUE;
 	} else {
 		vgic_v3->vgic_sre = 0;