FROMLIST: virt: gunyah: Add irqfd interface
Enable support for creating irqfds which can raise an interrupt on a Gunyah virtual machine. irqfds are exposed to userspace as a Gunyah VM function with the name "irqfd". If the VM devicetree is not configured to create a doorbell with the corresponding label, userspace will still be able to assert the eventfd but no interrupt will be raised on the guest. Bug: 338347082 Link: https://lore.kernel.org/all/20240222-gunyah-v17-32-1e9da6763d38@quicinc.com/ Change-Id: I642ff862db1268cc5195346f79ed96573a9ba492 Acked-by: Alex Elder <elder@linaro.org> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> [Elliot: s/fd.file/fd_file(fd)/] Signed-off-by: Elliot Berman <elliot.berman@oss.qualcomm.com>
This commit is contained in:
Elliot Berman
committed by
Treehugger Robot
Treehugger Robot
parent
35eb2b9248
commit
bacbc71692
@@ -27,3 +27,12 @@ config GUNYAH_QCOM_PLATFORM
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extra platform-specific support.
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Say Y/M here to use Gunyah on Qualcomm platforms.
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config GUNYAH_IRQFD
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tristate "Gunyah irqfd interface"
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depends on GUNYAH
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help
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Enable kernel support for creating irqfds which can raise an interrupt
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on Gunyah virtual machine.
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Say Y/M here if unsure and you want to support Gunyah VMMs.
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@@ -5,3 +5,4 @@ gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mem.o guest_memfd.o
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obj-$(CONFIG_GUNYAH) += gunyah.o gunyah_rsc_mgr.o gunyah_vcpu.o
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obj-$(CONFIG_GUNYAH_PLATFORM_HOOKS) += gunyah_platform_hooks.o
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obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o
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obj-$(CONFIG_GUNYAH_IRQFD) += gunyah_irqfd.o
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@@ -0,0 +1,187 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
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*/
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#include <linux/eventfd.h>
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#include <linux/device/driver.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/gunyah.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/printk.h>
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#include <uapi/linux/gunyah.h>
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struct gunyah_irqfd {
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struct gunyah_resource *ghrsc;
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struct gunyah_vm_resource_ticket ticket;
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struct gunyah_vm_function_instance *f;
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bool level;
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struct eventfd_ctx *ctx;
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wait_queue_entry_t wait;
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poll_table pt;
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};
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static int irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync,
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void *key)
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{
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struct gunyah_irqfd *irqfd =
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container_of(wait, struct gunyah_irqfd, wait);
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__poll_t flags = key_to_poll(key);
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int ret = 0;
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if (flags & EPOLLIN) {
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if (irqfd->ghrsc) {
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ret = gunyah_hypercall_bell_send(irqfd->ghrsc->capid, 1,
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NULL);
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if (ret)
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pr_err_ratelimited(
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"Failed to inject interrupt %d: %d\n",
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irqfd->ticket.label, ret);
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} else
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pr_err_ratelimited(
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"Premature injection of interrupt\n");
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}
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return 0;
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}
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static void irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
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poll_table *pt)
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{
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struct gunyah_irqfd *irq_ctx =
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container_of(pt, struct gunyah_irqfd, pt);
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add_wait_queue(wqh, &irq_ctx->wait);
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}
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static bool gunyah_irqfd_populate(struct gunyah_vm_resource_ticket *ticket,
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struct gunyah_resource *ghrsc)
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{
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struct gunyah_irqfd *irqfd =
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container_of(ticket, struct gunyah_irqfd, ticket);
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int ret;
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if (irqfd->ghrsc) {
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pr_warn("irqfd%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n",
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irqfd->ticket.label);
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return false;
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}
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irqfd->ghrsc = ghrsc;
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if (irqfd->level) {
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/* Configure the bell to trigger when bit 0 is asserted (see
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* irq_wakeup) and for bell to automatically clear bit 0 once
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* received by the VM (ack_mask). need to make sure bit 0 is cleared right away,
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* otherwise the line will never be deasserted. Emulating edge
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* trigger interrupt does not need to set either mask
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* because irq is listed only once per gunyah_hypercall_bell_send
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*/
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ret = gunyah_hypercall_bell_set_mask(irqfd->ghrsc->capid, 1, 1);
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if (ret)
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pr_warn("irq %d couldn't be set as level triggered. Might cause IRQ storm if asserted\n",
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irqfd->ticket.label);
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}
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return true;
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}
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static void gunyah_irqfd_unpopulate(struct gunyah_vm_resource_ticket *ticket,
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struct gunyah_resource *ghrsc)
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{
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}
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static long gunyah_irqfd_bind(struct gunyah_vm_function_instance *f)
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{
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struct gunyah_fn_irqfd_arg *args = f->argp;
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struct gunyah_irqfd *irqfd;
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__poll_t events;
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struct fd fd;
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long r;
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if (f->arg_size != sizeof(*args))
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return -EINVAL;
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/* All other flag bits are reserved for future use */
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if (args->flags & ~GUNYAH_IRQFD_FLAGS_LEVEL)
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return -EINVAL;
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irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
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if (!irqfd)
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return -ENOMEM;
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irqfd->f = f;
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f->data = irqfd;
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fd = fdget(args->fd);
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if (!fd_file(fd)) {
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kfree(irqfd);
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return -EBADF;
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}
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irqfd->ctx = eventfd_ctx_fileget(fd_file(fd));
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if (IS_ERR(irqfd->ctx)) {
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r = PTR_ERR(irqfd->ctx);
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goto err_fdput;
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}
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if (args->flags & GUNYAH_IRQFD_FLAGS_LEVEL)
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irqfd->level = true;
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init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
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init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
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irqfd->ticket.resource_type = GUNYAH_RESOURCE_TYPE_BELL_TX;
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irqfd->ticket.label = args->label;
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irqfd->ticket.owner = THIS_MODULE;
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irqfd->ticket.populate = gunyah_irqfd_populate;
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irqfd->ticket.unpopulate = gunyah_irqfd_unpopulate;
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r = gunyah_vm_add_resource_ticket(f->ghvm, &irqfd->ticket);
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if (r)
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goto err_ctx;
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events = vfs_poll(fd_file(fd), &irqfd->pt);
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if (events & EPOLLIN)
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pr_warn("Premature injection of interrupt\n");
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fdput(fd);
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return 0;
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err_ctx:
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eventfd_ctx_put(irqfd->ctx);
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err_fdput:
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fdput(fd);
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kfree(irqfd);
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return r;
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}
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static void gunyah_irqfd_unbind(struct gunyah_vm_function_instance *f)
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{
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struct gunyah_irqfd *irqfd = f->data;
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u64 cnt;
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eventfd_ctx_remove_wait_queue(irqfd->ctx, &irqfd->wait, &cnt);
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gunyah_vm_remove_resource_ticket(irqfd->f->ghvm, &irqfd->ticket);
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eventfd_ctx_put(irqfd->ctx);
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kfree(irqfd);
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}
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static bool gunyah_irqfd_compare(const struct gunyah_vm_function_instance *f,
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const void *arg, size_t size)
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{
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const struct gunyah_fn_irqfd_arg *instance = f->argp, *other = arg;
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if (sizeof(*other) != size)
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return false;
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return instance->label == other->label;
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}
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DECLARE_GUNYAH_VM_FUNCTION_INIT(irqfd, GUNYAH_FN_IRQFD, 2, gunyah_irqfd_bind,
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gunyah_irqfd_unbind, gunyah_irqfd_compare);
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MODULE_DESCRIPTION("Gunyah irqfd VM Function");
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MODULE_LICENSE("GPL");
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@@ -63,9 +63,12 @@ struct gunyah_vm_dtb_config {
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* @GUNYAH_FN_VCPU: create a vCPU instance to control a vCPU
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* &struct gunyah_fn_desc.arg is a pointer to &struct gunyah_fn_vcpu_arg
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* Return: file descriptor to manipulate the vcpu.
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* @GUNYAH_FN_IRQFD: register eventfd to assert a Gunyah doorbell
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* &struct gunyah_fn_desc.arg is a pointer to &struct gunyah_fn_irqfd_arg
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*/
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enum gunyah_fn_type {
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GUNYAH_FN_VCPU = 1,
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GUNYAH_FN_IRQFD,
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};
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#define GUNYAH_FN_MAX_ARG_SIZE 256
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@@ -85,6 +88,38 @@ struct gunyah_fn_vcpu_arg {
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__u32 id;
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};
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/**
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* enum gunyah_irqfd_flags - flags for use in gunyah_fn_irqfd_arg
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* @GUNYAH_IRQFD_FLAGS_LEVEL: make the interrupt operate like a level triggered
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* interrupt on guest side. Triggering IRQFD before
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* guest handles the interrupt causes interrupt to
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* stay asserted.
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*/
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enum gunyah_irqfd_flags {
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GUNYAH_IRQFD_FLAGS_LEVEL = 1UL << 0,
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};
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/**
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* struct gunyah_fn_irqfd_arg - Arguments to create an irqfd function.
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*
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* Create this function with &GUNYAH_VM_ADD_FUNCTION using type &GUNYAH_FN_IRQFD.
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*
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* Allows setting an eventfd to directly trigger a guest interrupt.
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* irqfd.fd specifies the file descriptor to use as the eventfd.
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* irqfd.label corresponds to the doorbell label used in the guest VM's devicetree.
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*
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* @fd: an eventfd which when written to will raise a doorbell
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* @label: Label of the doorbell created on the guest VM
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* @flags: see &enum gunyah_irqfd_flags
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* @padding: padding bytes
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*/
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struct gunyah_fn_irqfd_arg {
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__u32 fd;
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__u32 label;
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__u32 flags;
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__u32 padding;
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};
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/**
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* struct gunyah_fn_desc - Arguments to create a VM function
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* @type: Type of the function. See &enum gunyah_fn_type.
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