Messages in this thread | | | Date | Fri, 31 Mar 2023 09:27:01 -0500 | From | Alex Elder <> | Subject | Re: [PATCH v11 20/26] virt: gunyah: Add resource tickets |
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On 3/3/23 7:06 PM, Elliot Berman wrote: > Some VM functions need to acquire Gunyah resources. For instance, Gunyah > vCPUs are exposed to the host as a resource. The Gunyah vCPU function > will register a resource ticket and be able to interact with the > hypervisor once the resource ticket is filled. > > Resource tickets are the mechanism for functions to acquire ownership of > Gunyah resources. Gunyah functions can be created before the VM's > resources are created and made available to Linux. A resource ticket > identifies a type of resource and a label of a resource which the ticket > holder is interested in. > > Resources are created by Gunyah as configured in the VM's devicetree > configuration. Gunyah doesn't process the label and that makes it > possible for userspace to create multiple resources with the same label. > Resource ticket owners need to be prepared for populate to be called > multiple times if userspace created multiple resources with the same > label. > > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
One possibly substantive suggestion here, plus a couple suggestions to add or revise comments.
-Alex
> --- > drivers/virt/gunyah/vm_mgr.c | 112 +++++++++++++++++++++++++++++++++- > drivers/virt/gunyah/vm_mgr.h | 4 ++ > include/linux/gunyah_vm_mgr.h | 14 +++++ > 3 files changed, 129 insertions(+), 1 deletion(-) > > diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c > index 88db011395ec..0269bcdaf692 100644 > --- a/drivers/virt/gunyah/vm_mgr.c > +++ b/drivers/virt/gunyah/vm_mgr.c > @@ -165,6 +165,74 @@ static long gh_vm_rm_function(struct gh_vm *ghvm, struct gh_fn_desc *f) > return r; > } > > +int gh_vm_add_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket) > +{ > + struct gh_vm_resource_ticket *iter; > + struct gh_resource *ghrsc; > + int ret = 0; > + > + mutex_lock(&ghvm->resources_lock); > + list_for_each_entry(iter, &ghvm->resource_tickets, list) { > + if (iter->resource_type == ticket->resource_type && iter->label == ticket->label) { > + ret = -EEXIST; > + goto out; > + } > + } > + > + if (!try_module_get(ticket->owner)) { > + ret = -ENODEV; > + goto out; > + } > + > + list_add(&ticket->list, &ghvm->resource_tickets); > + INIT_LIST_HEAD(&ticket->resources); > + > + list_for_each_entry(ghrsc, &ghvm->resources, list) { > + if (ghrsc->type == ticket->resource_type && ghrsc->rm_label == ticket->label) { > + if (!ticket->populate(ticket, ghrsc)) > + list_move(&ghrsc->list, &ticket->resources); > + } > + } > +out: > + mutex_unlock(&ghvm->resources_lock); > + return ret; > +} > +EXPORT_SYMBOL_GPL(gh_vm_add_resource_ticket); > + > +void gh_vm_remove_resource_ticket(struct gh_vm *ghvm, struct gh_vm_resource_ticket *ticket) > +{ > + struct gh_resource *ghrsc, *iter; > + > + mutex_lock(&ghvm->resources_lock); > + list_for_each_entry_safe(ghrsc, iter, &ticket->resources, list) { > + ticket->unpopulate(ticket, ghrsc); > + list_move(&ghrsc->list, &ghvm->resources); > + } > + > + module_put(ticket->owner); > + list_del(&ticket->list); > + mutex_unlock(&ghvm->resources_lock); > +} > +EXPORT_SYMBOL_GPL(gh_vm_remove_resource_ticket); > + > +static void gh_vm_add_resource(struct gh_vm *ghvm, struct gh_resource *ghrsc) > +{ > + struct gh_vm_resource_ticket *ticket; > + > + mutex_lock(&ghvm->resources_lock); > + list_for_each_entry(ticket, &ghvm->resource_tickets, list) { > + if (ghrsc->type == ticket->resource_type && ghrsc->rm_label == ticket->label) { > + if (!ticket->populate(ticket, ghrsc)) { > + list_add(&ghrsc->list, &ticket->resources); > + goto found; > + }
I think the "goto found" belongs here, unconditionally. You disallow adding more than one ticket of a given type with the same label. So you will never match another ticket once you've matched this one.
The populate function generally shouldn't fail. I think it only fails if you find a duplicate, and again, I think you prevent that from happening. (But if it does, you silently ignore it...)
> + } > + } > + list_add(&ghrsc->list, &ghvm->resources); > +found: > + mutex_unlock(&ghvm->resources_lock); > +} > + > static int gh_vm_rm_notification_status(struct gh_vm *ghvm, void *data) > { > struct gh_rm_vm_status_payload *payload = data; > @@ -230,6 +298,8 @@ static void gh_vm_free(struct work_struct *work) > { > struct gh_vm *ghvm = container_of(work, struct gh_vm, free_work); > struct gh_vm_function_instance *inst, *iiter; > + struct gh_vm_resource_ticket *ticket, *titer; > + struct gh_resource *ghrsc, *riter; > struct gh_vm_mem *mapping, *tmp; > int ret; > > @@ -246,6 +316,25 @@ static void gh_vm_free(struct work_struct *work) > } > mutex_unlock(&ghvm->fn_lock); > > + mutex_lock(&ghvm->resources_lock); > + if (!list_empty(&ghvm->resource_tickets)) { > + dev_warn(ghvm->parent, "Dangling resource tickets:\n"); > + list_for_each_entry_safe(ticket, titer, &ghvm->resource_tickets, list) { > + dev_warn(ghvm->parent, " %pS\n", ticket->populate); > + gh_vm_remove_resource_ticket(ghvm, ticket); > + } > + } > + > + list_for_each_entry_safe(ghrsc, riter, &ghvm->resources, list) { > + gh_rm_free_resource(ghrsc); > + } > + mutex_unlock(&ghvm->resources_lock); > + > + ret = gh_rm_vm_reset(ghvm->rm, ghvm->vmid); > + if (ret) > + dev_err(ghvm->parent, "Failed to reset the vm: %d\n", ret); > + wait_event(ghvm->vm_status_wait, ghvm->vm_status == GH_RM_VM_STATUS_RESET); > + > mutex_lock(&ghvm->mm_lock); > list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) { > gh_vm_mem_reclaim(ghvm, mapping); > @@ -329,6 +418,9 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm) > init_rwsem(&ghvm->status_lock); > INIT_WORK(&ghvm->free_work, gh_vm_free); > kref_init(&ghvm->kref); > + mutex_init(&ghvm->resources_lock); > + INIT_LIST_HEAD(&ghvm->resources); > + INIT_LIST_HEAD(&ghvm->resource_tickets); > INIT_LIST_HEAD(&ghvm->functions); > ghvm->vm_status = GH_RM_VM_STATUS_LOAD; > > @@ -338,9 +430,11 @@ static __must_check struct gh_vm *gh_vm_alloc(struct gh_rm *rm) > static int gh_vm_start(struct gh_vm *ghvm) > { > struct gh_vm_mem *mapping; > + struct gh_rm_hyp_resources *resources; > + struct gh_resource *ghrsc; > u64 dtb_offset; > u32 mem_handle; > - int ret; > + int ret, i, n; > > down_write(&ghvm->status_lock); > if (ghvm->vm_status != GH_RM_VM_STATUS_LOAD) { > @@ -394,6 +488,22 @@ static int gh_vm_start(struct gh_vm *ghvm) > goto err; > } > > + ret = gh_rm_get_hyp_resources(ghvm->rm, ghvm->vmid, &resources); > + if (ret) { > + dev_warn(ghvm->parent, "Failed to get hypervisor resources for VM: %d\n", ret); > + goto err; > + } > + > + for (i = 0, n = le32_to_cpu(resources->n_entries); i < n; i++) { > + ghrsc = gh_rm_alloc_resource(ghvm->rm, &resources->entries[i]); > + if (!ghrsc) { > + ret = -ENOMEM; > + goto err; > + } > + > + gh_vm_add_resource(ghvm, ghrsc); > + } > + > ret = gh_rm_vm_start(ghvm->rm, ghvm->vmid); > if (ret) { > dev_warn(ghvm->parent, "Failed to start VM: %d\n", ret); > diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h > index 7bd271bad721..18d0e1effd25 100644 > --- a/drivers/virt/gunyah/vm_mgr.h > +++ b/drivers/virt/gunyah/vm_mgr.h > @@ -7,6 +7,7 @@ > #define _GH_PRIV_VM_MGR_H > > #include <linux/gunyah_rsc_mgr.h> > +#include <linux/gunyah_vm_mgr.h> > #include <linux/list.h> > #include <linux/kref.h> > #include <linux/miscdevice.h> > @@ -51,6 +52,9 @@ struct gh_vm { > struct list_head memory_mappings; > struct mutex fn_lock; > struct list_head functions; > + struct mutex resources_lock; > + struct list_head resources; > + struct list_head resource_tickets; > }; > > int gh_vm_mem_alloc(struct gh_vm *ghvm, struct gh_userspace_memory_region *region); > diff --git a/include/linux/gunyah_vm_mgr.h b/include/linux/gunyah_vm_mgr.h > index 3825c951790a..01b1761b5923 100644 > --- a/include/linux/gunyah_vm_mgr.h > +++ b/include/linux/gunyah_vm_mgr.h > @@ -70,4 +70,18 @@ void gh_vm_function_unregister(struct gh_vm_function *f); > DECLARE_GH_VM_FUNCTION(_name, _type, _bind, _unbind); \ > module_gh_vm_function(_name) > > +struct gh_vm_resource_ticket { > + struct list_head list; /* for gh_vm's resources list */
Maybe "resource lists" above (it's for the resources list and resource_tickets list).
> + struct list_head resources; /* for gh_resources's list */
Maybe: /* resources associated with this ticket */
> + enum gh_resource_type resource_type; > + u32 label; > + > + struct module *owner; > + int (*populate)(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc); > + void (*unpopulate)(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc); > +}; > + > +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); > + > #endif
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