Re: [PATCH v2] irqchip/gicv3-its: Don't allow devices whose ID is outside range

[Shanker Donthineni]

Hi Eric,

On 03/01/2016 03:42 AM, Eric Auger wrote:
> Hi Shanker,
> On 02/28/2016 08:22 PM, 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 sparse
> space?
Sure, I will change to 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.
> >
> > Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
> > ---
> > [v1]->[v2]
> >    Rebase to v4.5-rc6, edit commit text and simplify code changes
> >
> >   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 memeory information and table
> typo: memory

Thanks, I will fix in next patch.
> Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
>
> Best Regards
>
> Eric
> > + * 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