Re: [PATCH v3] irqchip/gicv3-its: Don't allow devices whose ID is outside range

Shanker Donthineni
2016-03-03T14:34:47Z

Hi Marc,

Do you have any comments on this patch?

On 03/01/2016 06:55 AM, Shanker Donthineni wrote:
> We are not checking whether the requested device identifier fits into
> the device table memory or not. The function its_create_device()
> assumes that enough memory has been allocated for whole DevID space
> (reported by ITS_TYPER.Devbits) during the ITS probe() and continues
> to initialize ITS hardware.
>
> This assumption is not perfect, sometimes we reduce memory size either
> because of its size crossing MAX_ORDER-1 or BASERn max size limit. The
> MAPD command fails if 'Device ID' is outside of device table range.
>
> Add a simple validation check to avoid MAPD failures since we are
> not handling ITS command errors. This change also helps to return an
> error -ENOMEM instead of success to caller.
>
> Reviewed-by: Eric Auger <eric.auger@linaro.org>
> Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
> ---
> [v1]->[v2]
> Rebase to v4.5-rc6, edit commit text and simplify code changes.
>
> [v2]->[v3]
> Fix typo.
>
> drivers/irqchip/irq-gic-v3-its.c | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 43dfd15..6d986ac 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -55,6 +55,16 @@ struct its_collection {
> };
>
> /*
> + * The ITS_BASER structure - contains memory information and table
> + * entry size in bytes.
> + */
> +struct its_baser {
> + void *base;
> + u32 order;
> + u32 entry_size;
> +};
> +
> +/*
> * The ITS structure - contains most of the infrastructure, with the
> * top-level MSI domain, the command queue, the collections, and the
> * list of devices writing to it.
> @@ -66,14 +76,12 @@ struct its_node {
> unsigned long phys_base;
> struct its_cmd_block *cmd_base;
> struct its_cmd_block *cmd_write;
> - struct {
> - void *base;
> - u32 order;
> - } tables[GITS_BASER_NR_REGS];
> + struct its_baser tables[GITS_BASER_NR_REGS];
> struct its_collection *collections;
> struct list_head its_device_list;
> u64 flags;
> u32 ite_size;
> + struct its_baser *device_table;
> };
>
> #define ITS_ITT_ALIGN SZ_256
> @@ -860,6 +868,7 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
> * For other tables, only allocate a single page.
> */
> if (type == GITS_BASER_TYPE_DEVICE) {
> + its->device_table = &its->tables[i];
> /*
> * 'order' was initialized earlier to the default page
> * granule of the the ITS. We can't have an allocation
> @@ -874,6 +883,7 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
> node_name, order);
> }
> }
> + its->tables[i].entry_size = entry_size;
>
> retry_alloc_baser:
> alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
> @@ -1152,6 +1162,12 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
> int nr_ites;
> int sz;
>
> + /* Don't allow 'dev_id' that exceeds single, flat table limit */
> + if (its->device_table &&
> + (dev_id >= (PAGE_ORDER_TO_SIZE(its->device_table->order) /
> + its->device_table->entry_size)))
> + return NULL;
> +
> dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> /*
> * At least one bit of EventID is being used, hence a minimum

--
Shanker Donthineni
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project