Re: [PATCH] xen/pciback: Fix conf_space read/write overlap check.

[Juergen Gross]

On 21/06/16 17:52, Boris Ostrovsky wrote:
> On 06/21/2016 10:37 AM, Andrey Grodzovsky wrote:
>> Current overlap check is evaluating to false a case where a filter field
>> is fully contained (proper subset) of a r/w request.
>> This change applies classical overlap check instead to include
>> all the scenarios.
>>
>> Related to https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxx/msg72174.html
>>
>> Cc: Jan Beulich <JBeulich@xxxxxxxx>
>> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Andrey Grodzovsky <andrey2805@xxxxxxxxx>
> 
> + David and Juergen (maintainers) and kernel list.
> 
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>

Acked-by: Juergen Gross <jgross@xxxxxxxx>

> 
> 
>> ---
>>  drivers/xen/xen-pciback/conf_space.c | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/xen/xen-pciback/conf_space.c b/drivers/xen/xen-pciback/conf_space.c
>> index 8e67336..6a25533 100644
>> --- a/drivers/xen/xen-pciback/conf_space.c
>> +++ b/drivers/xen/xen-pciback/conf_space.c
>> @@ -183,8 +183,7 @@ int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size,
>>  		field_start = OFFSET(cfg_entry);
>>  		field_end = OFFSET(cfg_entry) + field->size;
>>  
>> -		if ((req_start >= field_start && req_start < field_end)
>> -		    || (req_end > field_start && req_end <= field_end)) {
>> +		 if (req_end > field_start && field_end > req_start) {
>>  			err = conf_space_read(dev, cfg_entry, field_start,
>>  					      &tmp_val);
>>  			if (err)
>> @@ -230,8 +229,7 @@ int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value)
>>  		field_start = OFFSET(cfg_entry);
>>  		field_end = OFFSET(cfg_entry) + field->size;
>>  
>> -		if ((req_start >= field_start && req_start < field_end)
>> -		    || (req_end > field_start && req_end <= field_end)) {
>> +		 if (req_end > field_start && field_end > req_start) {
>>  			tmp_val = 0;
>>  
>>  			err = xen_pcibk_config_read(dev, field_start,
> 
> 
>