[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN][PATCH v5 14/17] xen/arm: Implement device tree node addition functionalities
Hi Vikram, On 11/04/2023 21:16, Vikram Garhwal wrote: > > > Update sysctl XEN_SYSCTL_dt_overlay to enable support for dtbo nodes addition > using device tree overlay. > > xl dt-overlay add file.dtbo: > Each time overlay nodes are added using .dtbo, a new fdt(memcpy of > device_tree_flattened) is created and updated with overlay nodes. This > updated fdt is further unflattened to a dt_host_new. Next, it checks if > any > of the overlay nodes already exists in the dt_host. If overlay nodes > doesn't > exist then find the overlay nodes in dt_host_new, find the overlay node's > parent in dt_host and add the nodes as child under their parent in the > dt_host. The node is attached as the last node under target parent. > > Finally, add IRQs, add device to IOMMUs, set permissions and map MMIO for > the > overlay node. > > When a node is added using overlay, a new entry is allocated in the > overlay_track to keep the track of memory allocation due to addition of > overlay > node. This is helpful for freeing the memory allocated when a device tree node > is removed. > > The main purpose of this to address first part of dynamic programming i.e. > making xen aware of new device tree node which means updating the dt_host with > overlay node information. Here we are adding/removing node from dt_host, and > checking/setting IOMMU and IRQ permission but never mapping them to any > domain. > Right now, mapping/Un-mapping will happen only when a new domU is > created/destroyed using "xl create". > > Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx> > --- > xen/common/dt_overlay.c | 482 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 482 insertions(+) > > diff --git a/xen/common/dt_overlay.c b/xen/common/dt_overlay.c > index 516e8010c5..3344bad313 100644 > --- a/xen/common/dt_overlay.c > +++ b/xen/common/dt_overlay.c > @@ -36,6 +36,25 @@ static struct dt_device_node *find_last_descendants_node( > return child_node; > } > > +/* > + * Returns next node to the input node. If node has children then return > + * last descendant's next node. > +*/ > +static struct dt_device_node *dt_find_next_node(struct dt_device_node *dt, > + const struct dt_device_node > *node) This should be: static struct dt_device_node * dt_find_next_node(struct dt_device_node *dt, const struct dt_device_node *node) > +{ > + struct dt_device_node *np; > + > + dt_for_each_device_node(dt, np) > + if ( np == node ) > + break; > + > + if ( np->child ) > + np = find_last_descendants_node(np); > + > + return np->allnext; > +} > + > static int dt_overlay_remove_node(struct dt_device_node *device_node) > { > struct dt_device_node *np; > @@ -109,6 +128,72 @@ static int dt_overlay_remove_node(struct dt_device_node > *device_node) > return 0; > } > > +static int dt_overlay_add_node(struct dt_device_node *device_node, > + const char *parent_node_path) > +{ > + struct dt_device_node *parent_node; > + struct dt_device_node *np, *np_last_descendant; > + struct dt_device_node *next_node; > + struct dt_device_node *device_node_last_descendant; You can limit the scope of at least 3 variables above. > + > + parent_node = dt_find_node_by_path(parent_node_path); > + > + if ( parent_node == NULL ) > + { > + dt_dprintk("Node not found. Overlay node will not be added\n"); It would help if you print the node name. > + return -EINVAL; > + } > + > + /* If parent has no child. */ > + if ( parent_node->child == NULL ) > + { > + next_node = parent_node->allnext; > + device_node->parent = parent_node; > + parent_node->allnext = device_node; > + parent_node->child = device_node; > + } > + else > + { > + /* If parent has at least one child node. > + * Iterate to the last child node of parent. > + */ > + for ( np = parent_node->child; np->sibling != NULL; np = np->sibling > ); NIT: Your empty for() loop is not consistent. Here you use ; and somewhere else {}. > + > + /* Iterate over all child nodes of np node. */ > + if ( np->child ) > + { > + np_last_descendant = find_last_descendants_node(np); > + > + next_node = np_last_descendant->allnext; > + np_last_descendant->allnext = device_node; > + } > + else > + { > + next_node = np->allnext; > + np->allnext = device_node; > + } > + > + device_node->parent = parent_node; > + np->sibling = device_node; > + np->sibling->sibling = NULL; > + } > + > + /* Iterate over all child nodes of device_node to add children too. */ > + if ( device_node->child ) > + { > + device_node_last_descendant = > find_last_descendants_node(device_node); > + /* Plug next_node at the end of last children of device_node. */ > + device_node_last_descendant->allnext = next_node; > + } > + else > + { > + /* Now plug next_node at the end of device_node. */ > + device_node->allnext = next_node; > + } > + > + return 0; > +} > + > /* Basic sanity check for the dtbo tool stack provided to Xen. */ > static int check_overlay_fdt(const void *overlay_fdt, uint32_t > overlay_fdt_size) > { > @@ -148,6 +233,79 @@ static unsigned int overlay_node_count(void *fdto) > return num_overlay_nodes; > } > > +/* > + * overlay_get_nodes_info will get full name with path for all the nodes > which s/will get/gets > + * are in one level of __overlay__ tag. This is useful when checking node for > + * duplication i.e. dtbo tries to add nodes which already exists in device > tree. > + */ > +static int overlay_get_nodes_info(const void *fdto, char ***nodes_full_path, > + unsigned int num_overlay_nodes) > +{ > + int fragment; > + > + *nodes_full_path = xzalloc_bytes(num_overlay_nodes * sizeof(char *)); > + > + if ( *nodes_full_path == NULL ) > + return -ENOMEM; > + > + fdt_for_each_subnode(fragment, fdto, 0) > + { > + int target; > + int overlay; > + int subnode; > + const char *target_path; > + > + target = fdt_overlay_target_offset(device_tree_flattened, fdto, > + fragment, &target_path); Shouldn't you also check if target_path is not NULL? I can see that it is possible for fdt_overlay_target_offset() to return >= 0 and NULL as target_path. > + if ( target < 0 ) > + return target; > + > + overlay = fdt_subnode_offset(fdto, fragment, "__overlay__"); > + > + /* > + * overlay value can be < 0. But fdt_for_each_subnode() loop checks > for > + * overlay >= 0. So, no need for a overlay>=0 check here. > + */ > + fdt_for_each_subnode(subnode, fdto, overlay) > + { > + const char *node_name = NULL; > + int node_name_len; > + unsigned int target_path_len = strlen(target_path); > + unsigned int node_full_name_len; > + unsigned int node_num = 0; > + > + node_name = fdt_get_name(fdto, subnode, &node_name_len); > + > + if ( node_name == NULL ) > + return node_name_len; > + > + /* > + * Magic number 2 is for adding '/'. This is done to keep the I think this is 2 because of adding both '/' and '\0'. > + * node_full_name in the correct full node name format. No such variable as node_full_name > + */ > + node_full_name_len = target_path_len + node_name_len + 2; > + > + (*nodes_full_path)[node_num] = xmalloc_bytes(node_full_name_len); > + > + if ( (*nodes_full_path)[node_num] == NULL ) > + return -ENOMEM; > + > + memcpy((*nodes_full_path)[node_num], target_path, > target_path_len); > + > + (*nodes_full_path)[node_num][target_path_len] = '/'; > + > + memcpy((*nodes_full_path)[node_num] + target_path_len + 1, > + node_name, node_name_len); > + > + (*nodes_full_path)[node_num][node_full_name_len - 1] = '\0'; > + > + node_num++; > + } > + } > + > + return 0; > +} > + > static int handle_remove_irq_iommu(struct dt_device_node *device_node) > { > int rc = 0; > @@ -367,6 +525,322 @@ out: > return rc; > } > > +/* > + * Handles IRQ and IOMMU mapping for the overlay_node and all descendants of > the > + * overlay_nodes. s/overlay_nodes/overlay_node/ ? > + */ > +static int handle_add_irq_iommu(struct domain *d, > + struct dt_device_node *overlay_node) > +{ > + int rc; > + unsigned int naddr, i, len; > + uint64_t addr, size; Please limit the scope > + struct dt_device_node *np; > + > + /* First let's handle the interrupts. */ > + rc = handle_device_interrupts(d, overlay_node, false); > + if ( rc < 0 ) > + { > + printk(XENLOG_ERR "Interrupt failed\n"); How about: "Failed to retrieve interrupts configuration" > + return rc; > + } > + > + /* Check if iommu property exists. */ > + if ( dt_get_property(overlay_node, "iommus", &len) ) > + { > + remove extra blank line > + /* Add device to IOMMUs. */ > + rc = iommu_add_dt_device(overlay_node); > + if ( rc < 0 ) > + { > + printk(XENLOG_ERR "Failed to add %s to the IOMMU\n", > + dt_node_full_name(overlay_node)); > + return rc; > + } > + } > + > + /* Set permissions. */ > + naddr = dt_number_of_address(overlay_node); > + > + dt_dprintk("%s passthrough = %d naddr = %u\n", Why do you need to print passthrough if it is always false? > + dt_node_full_name(overlay_node), false, naddr); > + > + /* Give permission for map MMIOs */ s/for/to/ > + for ( i = 0; i < naddr; i++ ) > + { > + /* > + * For now, we skip_mapping which means it will only permit iomem > access > + * to hardware_domain using iomem_permit_access() but will never map > as > + * map_range_p2mt() will not be called. > + */ > + struct map_range_data mr_data = { .d = d, > + .p2mt = p2m_mmio_direct_c, > + .skip_mapping = true }; }; should be placed on its own line > + > + rc = dt_device_get_address(overlay_node, i, &addr, &size); > + if ( rc ) > + { > + printk(XENLOG_ERR "Unable to retrieve address %u for %s\n", > + i, dt_node_full_name(overlay_node)); > + return rc; > + } > + > + rc = map_range_to_domain(overlay_node, addr, size, &mr_data); > + if ( rc ) > + return rc; > + } > + > + /* Map IRQ and IOMMU for overlay_node's children. */ > + for ( np = overlay_node->child; np != NULL; np = np->sibling) missing space before closing parenthesis > + { > + rc = handle_add_irq_iommu(d, np); > + if ( rc ) > + { > + printk(XENLOG_ERR "Adding IRQ and IOMMU failed\n"); > + return rc; > + } > + } > + > + return rc; > +} > + > +/* > + * Adds device tree nodes under target node. > + * We use tr->dt_host_new to unflatten the updated device_tree_flattened. > This > + * is done to avoid the removal of device_tree generation, iomem regions > mapping > + * to hardware domain done by handle_node(). > + */ > +static long handle_add_overlay_nodes(void *overlay_fdt, > + uint32_t overlay_fdt_size) > +{ > + int rc, j, i; > + struct dt_device_node *overlay_node, *prev_node, *next_node; Please limit the scope. > + struct domain *d = hardware_domain; No need for extra variable if it is only used in one place. Just use hardware_domain. > + struct overlay_track *tr = NULL; > + char **nodes_full_path = NULL; > + unsigned int new_fdt_size; > + > + tr = xzalloc(struct overlay_track); > + if ( tr == NULL ) > + return -ENOMEM; > + > + new_fdt_size = fdt_totalsize(device_tree_flattened) + > + fdt_totalsize(overlay_fdt); > + > + tr->fdt = xzalloc_bytes(new_fdt_size); > + if ( tr->fdt == NULL ) > + { > + xfree(tr); > + return -ENOMEM; > + } > + > + tr->num_nodes = overlay_node_count(overlay_fdt); > + if ( tr->num_nodes == 0 ) > + { > + xfree(tr->fdt); > + xfree(tr); > + return -ENOMEM; > + } > + > + tr->nodes_address = xzalloc_bytes(tr->num_nodes * sizeof(unsigned long)); > + if ( tr->nodes_address == NULL ) > + { > + xfree(tr->fdt); > + xfree(tr); > + return -ENOMEM; > + } > + > + rc = check_overlay_fdt(overlay_fdt, overlay_fdt_size); > + if ( rc ) > + { > + xfree(tr->nodes_address); > + xfree(tr->fdt); > + xfree(tr); > + return rc; > + } > + > + /* > + * Keep a copy of overlay_fdt as fdt_overlay_apply will change the input > + * overlay's content(magic) when applying overlay. > + */ > + tr->overlay_fdt = xzalloc_bytes(overlay_fdt_size); > + if ( tr->overlay_fdt == NULL ) > + { > + xfree(tr->nodes_address); > + xfree(tr->fdt); > + xfree(tr); > + return -ENOMEM; > + } > + > + memcpy(tr->overlay_fdt, overlay_fdt, overlay_fdt_size); > + > + spin_lock(&overlay_lock); > + > + memcpy(tr->fdt, device_tree_flattened, > + fdt_totalsize(device_tree_flattened)); > + > + /* Open tr->fdt with more space to accommodate the overlay_fdt. */ > + fdt_open_into(tr->fdt, tr->fdt, new_fdt_size); You are not checking the return value for an error. > + > + /* > + * overlay_get_nodes_info is called to get the node information from > dtbo. > + * This is done before fdt_overlay_apply() because the overlay apply will > + * erase the magic of overlay_fdt. > + */ > + rc = overlay_get_nodes_info(overlay_fdt, &nodes_full_path, > + tr->num_nodes); > + if ( rc ) > + { > + printk(XENLOG_ERR "Getting nodes information failed with error %d\n", > + rc); > + goto err; Looking at err: if you fail here, you will free dt_host_new which was not yet allocated. > + } > + > + rc = fdt_overlay_apply(tr->fdt, overlay_fdt); > + if ( rc ) > + { > + printk(XENLOG_ERR "Adding overlay node failed with error %d\n", rc); > + goto err; > + } > + > + /* > + * Check if any of the node already exists in dt_host. If node already > exits > + * we can return here as this overlay_fdt is not suitable for overlay > ops. > + */ > + for ( j = 0; j < tr->num_nodes; j++ ) > + { > + overlay_node = dt_find_node_by_path(nodes_full_path[j]); > + if ( overlay_node != NULL ) > + { > + printk(XENLOG_ERR "node %s exists in device tree\n", > + nodes_full_path[j]); > + rc = -EINVAL; > + goto err; > + } > + } > + > + /* Unflatten the tr->fdt into a new dt_host. */ > + unflatten_device_tree(tr->fdt, &tr->dt_host_new); > + > + for ( j = 0; j < tr->num_nodes; j++ ) > + { > + dt_dprintk("Adding node: %s\n", nodes_full_path[j]); > + > + /* Find the newly added node in tr->dt_host_new by it's full path. */ > + overlay_node = device_tree_find_node_by_path(tr->dt_host_new, > + nodes_full_path[j]); > + if ( overlay_node == NULL ) > + { > + dt_dprintk("%s node not found\n", nodes_full_path[j]); > + rc = -EFAULT; > + goto remove_node; You assing rc and go to remove_node which will overwrite it. Please fix. > + } > + > + /* > + * Find previous and next node to overlay_node in dt_host_new. We > will > + * need these nodes to fix the dt_host_new mapping. When > overlay_node is > + * take out of dt_host_new tree and added to dt_host, link between > + * previous node and next_node is broken. We will need to refresh > + * dt_host_new with correct linking for any other overlay nodes > + * extraction in future. > + */ > + dt_for_each_device_node(tr->dt_host_new, prev_node) > + if ( prev_node->allnext == overlay_node ) > + break; > + > + next_node = dt_find_next_node(tr->dt_host_new, overlay_node); > + > + read_lock(&dt_host->lock); > + > + /* Add the node to dt_host. */ > + rc = dt_overlay_add_node(overlay_node, > overlay_node->parent->full_name); > + if ( rc ) > + { > + read_unlock(&dt_host->lock); > + > + /* Node not added in dt_host. */ > + goto remove_node; > + } > + > + read_unlock(&dt_host->lock); > + > + prev_node->allnext = next_node; > + > + overlay_node = dt_find_node_by_path(overlay_node->full_name); > + if ( overlay_node == NULL ) > + { > + /* Sanity check. But code will never come here. */ > + ASSERT_UNREACHABLE(); > + goto remove_node; > + } > + > + rc = handle_add_irq_iommu(d, overlay_node); > + if ( rc ) > + { > + printk(XENLOG_ERR "Adding IRQ and IOMMU failed\n"); > + return rc; > + } > + > + /* Keep overlay_node address in tracker. */ > + tr->nodes_address[j] = (unsigned long)overlay_node; > + } > + > + INIT_LIST_HEAD(&tr->entry); > + list_add_tail(&tr->entry, &overlay_tracker); > + > + spin_unlock(&overlay_lock); > + > + if ( nodes_full_path != NULL ) > + { > + for ( i = 0; i < tr->num_nodes && nodes_full_path[i] != NULL; > + i++ ) > + { > + xfree(nodes_full_path[i]); > + } > + xfree(nodes_full_path); > + } > + > + return rc; > + > +/* > + * Failure case. We need to remove the nodes, free tracker(if tr exists) and > + * tr->dt_host_new. > + */ > +remove_node: > + tr->num_nodes = j; > + rc = remove_nodes(tr); > + > + if ( rc ) > + { > + /* If removing node fails, this may cause memory leaks. */ I think we are missing information why it is ok to leak memory. > + printk(XENLOG_ERR "Removing node failed.\n"); > + spin_unlock(&overlay_lock); > + return rc; > + } > + > +err: > + spin_unlock(&overlay_lock); > + > + xfree(tr->dt_host_new); > + xfree(tr->fdt); > + xfree(tr->overlay_fdt); > + xfree(tr->nodes_address); What is the order here? This does not look like reverse one. > + > + if ( nodes_full_path != NULL ) > + { > + for ( i = 0; i < tr->num_nodes && nodes_full_path[i] != NULL; > + i++ ) > + { > + xfree(nodes_full_path[i]); > + } > + xfree(nodes_full_path); > + } > + > + xfree(tr); > + > + return rc; > +} > + > long dt_sysctl(struct xen_sysctl_dt_overlay *op) > { > long ret; > @@ -391,6 +865,14 @@ long dt_sysctl(struct xen_sysctl_dt_overlay *op) > > switch ( op->overlay_op ) > { > + case XEN_SYSCTL_DT_OVERLAY_ADD: > + ret = handle_add_overlay_nodes(overlay_fdt, op->overlay_fdt_size); > + no need for extra blank line before checking the return value. > + if ( ret ) > + xfree(overlay_fdt); > + > + break; > + > case XEN_SYSCTL_DT_OVERLAY_REMOVE: > ret = handle_remove_overlay_nodes(overlay_fdt, op->overlay_fdt_size); > xfree(overlay_fdt); > -- > 2.17.1 > > ~Michal
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