Add framework for VM functions to handle stage-2 write faults from Gunyah guest virtual machines. IO handlers have a range of addresses which they apply to. Optionally, they may apply to only when the value written matches the IO handler's value. Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@xxxxxxxxxxx> Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx> --- drivers/virt/gunyah/vm_mgr.c | 104 ++++++++++++++++++++++++++++++++++ drivers/virt/gunyah/vm_mgr.h | 4 ++ include/linux/gunyah_vm_mgr.h | 25 ++++++++ 3 files changed, 133 insertions(+) diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c index 6228090aceb6..81b42ab675f6 100644 --- a/drivers/virt/gunyah/vm_mgr.c +++ b/drivers/virt/gunyah/vm_mgr.c @@ -279,6 +279,108 @@ static void gh_vm_clean_resources(struct gh_vm *ghvm) mutex_unlock(&ghvm->resources_lock); } +static int _gh_vm_io_handler_compare(const struct rb_node *node, const struct rb_node *parent) +{ + struct gh_vm_io_handler *n = container_of(node, struct gh_vm_io_handler, node); + struct gh_vm_io_handler *p = container_of(parent, struct gh_vm_io_handler, node); + + if (n->addr < p->addr) + return -1; + if (n->addr > p->addr) + return 1; + if ((n->len && !p->len) || (!n->len && p->len)) + return 0; + if (n->len < p->len) + return -1; + if (n->len > p->len) + return 1; + /* one of the io handlers doesn't have datamatch and the other does. + * For purposes of comparison, that makes them identical since the + * one that doesn't have datamatch will cover the same handler that + * does. + */ + if (n->datamatch != p->datamatch) + return 0; + if (n->data < p->data) + return -1; + if (n->data > p->data) + return 1; + return 0; +} + +static int gh_vm_io_handler_compare(struct rb_node *node, const struct rb_node *parent) +{ + return _gh_vm_io_handler_compare(node, parent); +} + +static int gh_vm_io_handler_find(const void *key, const struct rb_node *node) +{ + const struct gh_vm_io_handler *k = key; + + return _gh_vm_io_handler_compare(&k->node, node); +} + +static struct gh_vm_io_handler *gh_vm_mgr_find_io_hdlr(struct gh_vm *ghvm, u64 addr, + u64 len, u64 data) +{ + struct gh_vm_io_handler key = { + .addr = addr, + .len = len, + .datamatch = true, + .data = data, + }; + struct rb_node *node; + + node = rb_find(&key, &ghvm->mmio_handler_root, gh_vm_io_handler_find); + if (!node) + return NULL; + + return container_of(node, struct gh_vm_io_handler, node); +} + +int gh_vm_mmio_write(struct gh_vm *ghvm, u64 addr, u32 len, u64 data) +{ + struct gh_vm_io_handler *io_hdlr = NULL; + int ret; + + down_read(&ghvm->mmio_handler_lock); + io_hdlr = gh_vm_mgr_find_io_hdlr(ghvm, addr, len, data); + if (!io_hdlr || !io_hdlr->ops || !io_hdlr->ops->write) { + ret = -ENODEV; + goto out; + } + + ret = io_hdlr->ops->write(io_hdlr, addr, len, data); + +out: + up_read(&ghvm->mmio_handler_lock); + return ret; +} +EXPORT_SYMBOL_GPL(gh_vm_mmio_write); + +int gh_vm_add_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_hdlr) +{ + struct rb_node *found; + + if (io_hdlr->datamatch && (!io_hdlr->len || io_hdlr->len > sizeof(io_hdlr->data))) + return -EINVAL; + + down_write(&ghvm->mmio_handler_lock); + found = rb_find_add(&io_hdlr->node, &ghvm->mmio_handler_root, gh_vm_io_handler_compare); + up_write(&ghvm->mmio_handler_lock); + + return found ? -EEXIST : 0; +} +EXPORT_SYMBOL_GPL(gh_vm_add_io_handler); + +void gh_vm_remove_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_hdlr) +{ + down_write(&ghvm->mmio_handler_lock); + rb_erase(&io_hdlr->node, &ghvm->mmio_handler_root); + up_write(&ghvm->mmio_handler_lock); +} +EXPORT_SYMBOL_GPL(gh_vm_remove_io_handler); + static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data) { struct gh_rm_vm_status_payload *payload = data; @@ -364,6 +466,8 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm) mutex_init(&ghvm->resources_lock); INIT_LIST_HEAD(&ghvm->resources); INIT_LIST_HEAD(&ghvm->resource_tickets); + init_rwsem(&ghvm->mmio_handler_lock); + ghvm->mmio_handler_root = RB_ROOT; INIT_LIST_HEAD(&ghvm->functions); ghvm->vm_status = GH_RM_VM_STATUS_NO_STATE; diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h index e5e0c92d4cb1..3fc0f91dfd1a 100644 --- a/drivers/virt/gunyah/vm_mgr.h +++ b/drivers/virt/gunyah/vm_mgr.h @@ -56,10 +56,14 @@ struct gh_vm { struct mutex resources_lock; struct list_head resources; struct list_head resource_tickets; + struct rb_root mmio_handler_root; + struct rw_semaphore mmio_handler_lock; }; int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region); void gh_vm_mem_reclaim(struct gh_vm *ghvm); struct gh_vm_mem *gh_vm_mem_find_by_addr(struct gh_vm *ghvm, u64 guest_phys_addr, u32 size); +int gh_vm_mmio_write(struct gh_vm *ghvm, u64 addr, u32 len, u64 data); + #endif diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h index e3a6666d7529..0fa3cf6bcaca 100644 --- a/include/linux/gunyah_vm_mgr.h +++ b/include/linux/gunyah_vm_mgr.h @@ -98,4 +98,29 @@ struct gh_vm_resource_ticket { int gh_vm_add_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket); void gh_vm_remove_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket); +/* + * gh_vm_io_handler contains the info about an io device and its associated + * addr and the ops associated with the io device. + */ +struct gh_vm_io_handler { + struct rb_node node; + u64 addr; + + bool datamatch; + u8 len; + u64 data; + struct gh_vm_io_handler_ops *ops; +}; + +/* + * gh_vm_io_handler_ops contains function pointers associated with an iodevice. + */ +struct gh_vm_io_handler_ops { + int (*read)(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data); + int (*write)(struct gh_vm_io_handler *io_dev, u64 addr, u32 len, u64 data); +}; + +int gh_vm_add_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_dev); +void gh_vm_remove_io_handler(struct gh_vm *ghvm, struct gh_vm_io_handler *io_dev); + #endif -- 2.40.0