Enables support for injecting interrupts into guest vCPUs via KVM's
irqfd interface. Irqfds are requested from userspace via KVM_IRQFD
ioctl. kvm_arch_irqfd_init() implementation, in Gunyah, then creates
a resource ticket for the irqfd. The userspace must also create a
devicetree node to create a doorbell with the corresponding label.
Later after VM configuration (in gunyah_vm_start()), the resource ticket
will be populated and the irqfd instance will be bound to its
corresponding doorbell (identified with a capability id). When userspace
asserts the irq line, irqfd->set_irq() callback is called to inject an
interrupt into the guest via a hypercall.
Signed-off-by: Karim Manaouil <karim.manaouil@xxxxxxxxxx>
---
arch/arm64/kvm/gunyah.c | 100 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 100 insertions(+)
diff --git a/arch/arm64/kvm/gunyah.c b/arch/arm64/kvm/gunyah.c
index df922be2429e..23b9128bf5b1 100644
--- a/arch/arm64/kvm/gunyah.c
+++ b/arch/arm64/kvm/gunyah.c
@@ -29,6 +29,14 @@
#define WRITE_TAG (1 << 0)
#define SHARE_TAG (1 << 1)
+struct gunyah_irqfd {
+ struct gunyah_vm *ghvm;
+ struct gunyah_resource *ghrsc;
+ struct gunyah_vm_resource_ticket ticket;
+ struct kvm_kernel_irqfd irqfd;
+ bool level;
+};
+
static int gunyah_vm_start(struct gunyah_vm *ghvm);
static enum kvm_mode kvm_mode = KVM_MODE_DEFAULT;
@@ -852,6 +860,98 @@ static int gunyah_start_paging(struct gunyah_vm *ghvm)
return ret;
}
+static bool gunyah_irqfd_populate(struct gunyah_vm_resource_ticket *ticket,
+ struct gunyah_resource *ghrsc)
+{
+ struct gunyah_irqfd *irqfd =
+ container_of(ticket, struct gunyah_irqfd, ticket);
+ int ret;
+
+ if (irqfd->ghrsc) {
+ pr_warn("irqfd%d already got a Gunyah resource", irqfd->ticket.label);
+ return false;
+ }
+
+ irqfd->ghrsc = ghrsc;
+ if (irqfd->level) {
+ /* Configure the bell to trigger when bit 0 is asserted (see
+ * irq_wakeup) and for bell to automatically clear bit 0 once
+ * received by the VM (ack_mask). need to make sure bit 0 is cleared right away,
+ * otherwise the line will never be deasserted. Emulating edge
+ * trigger interrupt does not need to set either mask
+ * because irq is listed only once per gunyah_hypercall_bell_send
+ */
+ ret = gunyah_hypercall_bell_set_mask(irqfd->ghrsc->capid, 1, 1);
+ if (ret)
+ pr_warn("irq %d couldn't be set as level triggered."
+ "Might cause IRQ storm if asserted\n",
+ irqfd->ticket.label);
+ }
+
+ return true;
+}
+
+static void gunyah_irqfd_unpopulate(struct gunyah_vm_resource_ticket *ticket,
+ struct gunyah_resource *ghrsc)
+{
+}
+
+static int gunyah_set_irq(struct kvm_kernel_irqfd *kvm_irqfd)
+{
+ int ret;
+ struct gunyah_irqfd *irqfd =
+ container_of(kvm_irqfd, struct gunyah_irqfd, irqfd);
+
+ if (irqfd->ghrsc) {
+ if (gunyah_hypercall_bell_send(irqfd->ghrsc->capid, 1, NULL)) {
+ pr_err_ratelimited("Failed to inject interrupt %d: %d\n",
+ irqfd->ticket.label, ret);
+ return -1;
+ }
+ } else {
+ pr_err_ratelimited("Premature injection of interrupt\n");
+ return -1;
+ }
+
+ return 1;
+}
+
+struct kvm_kernel_irqfd *kvm_arch_irqfd_alloc(void)
+{
+ struct gunyah_irqfd *irqfd;
+
+ irqfd = kzalloc(sizeof(struct gunyah_irqfd), GFP_KERNEL);
+ if (!irqfd)
+ return NULL;
+
+ return &irqfd->irqfd;
+}
+
+void kvm_arch_irqfd_free(struct kvm_kernel_irqfd *kvm_irqfd)
+{
+ struct gunyah_irqfd *irqfd = container_of(kvm_irqfd, struct gunyah_irqfd, irqfd);
+
+ gunyah_vm_remove_resource_ticket(irqfd->ghvm, &irqfd->ticket);
+ kfree(irqfd);
+}
+
+int kvm_arch_irqfd_init(struct kvm_kernel_irqfd *kvm_irqfd)
+{
+ struct gunyah_vm *ghvm = container_of(kvm_irqfd->kvm, struct gunyah_vm, kvm);
+ struct gunyah_irqfd *irqfd = container_of(kvm_irqfd, struct gunyah_irqfd, irqfd);
+
+ kvm_irqfd->set_irq = gunyah_set_irq;
+
+ irqfd->ghvm = ghvm;
+
+ irqfd->ticket.resource_type = GUNYAH_RESOURCE_TYPE_BELL_TX;
+ irqfd->ticket.label = kvm_irqfd->gsi;
+ irqfd->ticket.populate = gunyah_irqfd_populate;
+ irqfd->ticket.unpopulate = gunyah_irqfd_unpopulate;
+
+ return gunyah_vm_add_resource_ticket(ghvm, &irqfd->ticket);
+}
+
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
--
2.39.5
