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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (c) 2023 MediaTek Inc.
- */
- #include <linux/eventfd.h>
- #include <linux/file.h>
- #include <linux/syscalls.h>
- #include <linux/gzvm.h>
- #include <linux/gzvm_drv.h>
- #include <linux/wait.h>
- #include <linux/poll.h>
- #include <linux/module.h>
- #include <linux/slab.h>
- struct gzvm_ioevent {
- struct list_head list;
- __u64 addr;
- __u32 len;
- struct eventfd_ctx *evt_ctx;
- __u64 datamatch;
- bool wildcard;
- };
- /**
- * ioeventfd_check_collision() - Check collison assumes gzvm->slots_lock held.
- * @gzvm: Pointer to gzvm.
- * @p: Pointer to gzvm_ioevent.
- *
- * Return:
- * * true - collison found
- * * false - no collison
- */
- static bool ioeventfd_check_collision(struct gzvm *gzvm, struct gzvm_ioevent *p)
- {
- struct gzvm_ioevent *_p;
- list_for_each_entry(_p, &gzvm->ioevents, list) {
- if (_p->addr == p->addr &&
- (!_p->len || !p->len ||
- (_p->len == p->len &&
- (_p->wildcard || p->wildcard ||
- _p->datamatch == p->datamatch))))
- return true;
- if (p->addr >= _p->addr && p->addr < _p->addr + _p->len)
- return true;
- }
- return false;
- }
- static void gzvm_ioevent_release(struct gzvm_ioevent *p)
- {
- eventfd_ctx_put(p->evt_ctx);
- list_del(&p->list);
- kfree(p);
- }
- static bool gzvm_ioevent_in_range(struct gzvm_ioevent *p, __u64 addr, int len,
- const void *val)
- {
- u64 _val;
- if (addr != p->addr)
- /* address must be precise for a hit */
- return false;
- if (!p->len)
- /* length = 0 means only look at the address, so always a hit */
- return true;
- if (len != p->len)
- /* address-range must be precise for a hit */
- return false;
- if (p->wildcard)
- /* all else equal, wildcard is always a hit */
- return true;
- /* otherwise, we have to actually compare the data */
- WARN_ON_ONCE(!IS_ALIGNED((unsigned long)val, len));
- switch (len) {
- case 1:
- _val = *(u8 *)val;
- break;
- case 2:
- _val = *(u16 *)val;
- break;
- case 4:
- _val = *(u32 *)val;
- break;
- case 8:
- _val = *(u64 *)val;
- break;
- default:
- return false;
- }
- return _val == p->datamatch;
- }
- static int gzvm_deassign_ioeventfd(struct gzvm *gzvm,
- struct gzvm_ioeventfd *args)
- {
- struct gzvm_ioevent *p, *tmp;
- struct eventfd_ctx *evt_ctx;
- int ret = -ENOENT;
- bool wildcard;
- evt_ctx = eventfd_ctx_fdget(args->fd);
- if (IS_ERR(evt_ctx))
- return PTR_ERR(evt_ctx);
- wildcard = !(args->flags & GZVM_IOEVENTFD_FLAG_DATAMATCH);
- mutex_lock(&gzvm->lock);
- list_for_each_entry_safe(p, tmp, &gzvm->ioevents, list) {
- if (p->evt_ctx != evt_ctx ||
- p->addr != args->addr ||
- p->len != args->len ||
- p->wildcard != wildcard)
- continue;
- if (!p->wildcard && p->datamatch != args->datamatch)
- continue;
- gzvm_ioevent_release(p);
- ret = 0;
- break;
- }
- mutex_unlock(&gzvm->lock);
- /* got in the front of this function */
- eventfd_ctx_put(evt_ctx);
- return ret;
- }
- static int gzvm_assign_ioeventfd(struct gzvm *gzvm, struct gzvm_ioeventfd *args)
- {
- struct eventfd_ctx *evt_ctx;
- struct gzvm_ioevent *evt;
- int ret;
- evt_ctx = eventfd_ctx_fdget(args->fd);
- if (IS_ERR(evt_ctx))
- return PTR_ERR(evt_ctx);
- evt = kmalloc(sizeof(*evt), GFP_KERNEL);
- if (!evt)
- return -ENOMEM;
- *evt = (struct gzvm_ioevent) {
- .addr = args->addr,
- .len = args->len,
- .evt_ctx = evt_ctx,
- };
- if (args->flags & GZVM_IOEVENTFD_FLAG_DATAMATCH) {
- evt->datamatch = args->datamatch;
- evt->wildcard = false;
- } else {
- evt->wildcard = true;
- }
- if (ioeventfd_check_collision(gzvm, evt)) {
- ret = -EEXIST;
- goto err_free;
- }
- mutex_lock(&gzvm->lock);
- list_add_tail(&evt->list, &gzvm->ioevents);
- mutex_unlock(&gzvm->lock);
- return 0;
- err_free:
- kfree(evt);
- eventfd_ctx_put(evt_ctx);
- return ret;
- }
- /**
- * gzvm_ioeventfd_check_valid() - Check user arguments is valid.
- * @args: Pointer to gzvm_ioeventfd.
- *
- * Return:
- * * true if user arguments are valid.
- * * false if user arguments are invalid.
- */
- static bool gzvm_ioeventfd_check_valid(struct gzvm_ioeventfd *args)
- {
- /* must be natural-word sized, or 0 to ignore length */
- switch (args->len) {
- case 0:
- case 1:
- case 2:
- case 4:
- case 8:
- break;
- default:
- return false;
- }
- /* check for range overflow */
- if (args->addr + args->len < args->addr)
- return false;
- /* check for extra flags that we don't understand */
- if (args->flags & ~GZVM_IOEVENTFD_VALID_FLAG_MASK)
- return false;
- /* ioeventfd with no length can't be combined with DATAMATCH */
- if (!args->len && (args->flags & GZVM_IOEVENTFD_FLAG_DATAMATCH))
- return false;
- /* gzvm does not support pio bus ioeventfd */
- if (args->flags & GZVM_IOEVENTFD_FLAG_PIO)
- return false;
- return true;
- }
- /**
- * gzvm_ioeventfd() - Register ioevent to ioevent list.
- * @gzvm: Pointer to gzvm.
- * @args: Pointer to gzvm_ioeventfd.
- *
- * Return:
- * * 0 - Success.
- * * Negative - Failure.
- */
- int gzvm_ioeventfd(struct gzvm *gzvm, struct gzvm_ioeventfd *args)
- {
- if (gzvm_ioeventfd_check_valid(args) == false)
- return -EINVAL;
- if (args->flags & GZVM_IOEVENTFD_FLAG_DEASSIGN)
- return gzvm_deassign_ioeventfd(gzvm, args);
- return gzvm_assign_ioeventfd(gzvm, args);
- }
- /**
- * gzvm_ioevent_write() - Travers this vm's registered ioeventfd to see if
- * need notifying it.
- * @vcpu: Pointer to vcpu.
- * @addr: mmio address.
- * @len: mmio size.
- * @val: Pointer to void.
- *
- * Return:
- * * true if this io is already sent to ioeventfd's listener.
- * * false if we cannot find any ioeventfd registering this mmio write.
- */
- bool gzvm_ioevent_write(struct gzvm_vcpu *vcpu, __u64 addr, int len,
- const void *val)
- {
- struct gzvm_ioevent *e;
- list_for_each_entry(e, &vcpu->gzvm->ioevents, list) {
- if (gzvm_ioevent_in_range(e, addr, len, val)) {
- eventfd_signal(e->evt_ctx, 1);
- return true;
- }
- }
- return false;
- }
- int gzvm_init_ioeventfd(struct gzvm *gzvm)
- {
- INIT_LIST_HEAD(&gzvm->ioevents);
- return 0;
- }
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