vhost-vdpa: honor CAP_IPC_LOCK
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Message ID 20210302091418.7226-1-jasowang@redhat.com
State New, archived
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Series
  • vhost-vdpa: honor CAP_IPC_LOCK
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Commit Message

Jason Wang March 2, 2021, 9:14 a.m. UTC
When CAP_IPC_LOCK is set we should not check locked memory against
rlimit as what has been implemented in mlock().

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/vdpa.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Michael S. Tsirkin March 2, 2021, 9:51 a.m. UTC | #1
On Tue, Mar 02, 2021 at 04:14:18AM -0500, Jason Wang wrote:
> When CAP_IPC_LOCK is set we should not check locked memory against
> rlimit as what has been implemented in mlock().
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Indeed and it's not just mlock.

Documentation/admin-guide/perf-security.rst:

RLIMIT_MEMLOCK and perf_event_mlock_kb resource constraints are ignored
for processes with the CAP_IPC_LOCK capability.

and let's add a Fixes: tag?

> ---
>  drivers/vhost/vdpa.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index ef688c8c0e0e..e93572e2e344 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -638,7 +638,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
>  	mmap_read_lock(dev->mm);
>  
>  	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> -	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
> +	if (!capable(CAP_IPC_LOCK) &&
> +	    (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit)) {
>  		ret = -ENOMEM;
>  		goto unlock;
>  	}
> -- 
> 2.18.1
Jason Wang March 2, 2021, 10:52 a.m. UTC | #2
On 2021/3/2 5:51 下午, Michael S. Tsirkin wrote:
> On Tue, Mar 02, 2021 at 04:14:18AM -0500, Jason Wang wrote:
>> When CAP_IPC_LOCK is set we should not check locked memory against
>> rlimit as what has been implemented in mlock().
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Indeed and it's not just mlock.
>
> Documentation/admin-guide/perf-security.rst:
>
> RLIMIT_MEMLOCK and perf_event_mlock_kb resource constraints are ignored
> for processes with the CAP_IPC_LOCK capability.
>
> and let's add a Fixes: tag?


Sure, V2 is posted.

Thanks


>
>> ---
>>   drivers/vhost/vdpa.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index ef688c8c0e0e..e93572e2e344 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -638,7 +638,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
>>   	mmap_read_lock(dev->mm);
>>   
>>   	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
>> -	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
>> +	if (!capable(CAP_IPC_LOCK) &&
>> +	    (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit)) {
>>   		ret = -ENOMEM;
>>   		goto unlock;
>>   	}
>> -- 
>> 2.18.1

Patch
diff mbox series

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index ef688c8c0e0e..e93572e2e344 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -638,7 +638,8 @@  static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	mmap_read_lock(dev->mm);
 
 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
-	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
+	if (!capable(CAP_IPC_LOCK) &&
+	    (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit)) {
 		ret = -ENOMEM;
 		goto unlock;
 	}