* [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size
@ 2025-07-01 14:40 Artem Sadovnikov
2025-07-11 21:00 ` Alex Williamson
2025-07-16 20:20 ` Alex Williamson
0 siblings, 2 replies; 4+ messages in thread
From: Artem Sadovnikov @ 2025-07-01 14:40 UTC (permalink / raw)
To: kvm
Cc: Artem Sadovnikov, Yishai Hadas, Jason Gunthorpe, Shameer Kolothum,
Kevin Tian, Alex Williamson, linux-kernel, lvc-project
MLX cap pg_track_log_max_msg_size consists of 5 bits, value of which is
used as power of 2 for max_msg_size. This can lead to multiplication
overflow between max_msg_size (u32) and integer constant, and afterwards
incorrect value is being written to rq_size.
Fix this issue by extending integer constant to u64 type.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
---
Changes from v1:
- The constant type was changed instead of variable type.
- The patch name was accidentally cut and is now fixed.
- LKML: https://lore.kernel.org/all/20250629095843.13349-1-a.sadovnikov@ispras.ru/
---
drivers/vfio/pci/mlx5/cmd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index 5b919a0b2524..a92b095b90f6 100644
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -1523,8 +1523,8 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
log_max_msg_size = MLX5_CAP_ADV_VIRTUALIZATION(mdev, pg_track_log_max_msg_size);
max_msg_size = (1ULL << log_max_msg_size);
/* The RQ must hold at least 4 WQEs/messages for successful QP creation */
- if (rq_size < 4 * max_msg_size)
- rq_size = 4 * max_msg_size;
+ if (rq_size < 4ULL * max_msg_size)
+ rq_size = 4ULL * max_msg_size;
memset(tracker, 0, sizeof(*tracker));
tracker->uar = mlx5_get_uars_page(mdev);
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size
2025-07-01 14:40 [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size Artem Sadovnikov
@ 2025-07-11 21:00 ` Alex Williamson
2025-07-13 7:56 ` Yishai Hadas
2025-07-16 20:20 ` Alex Williamson
1 sibling, 1 reply; 4+ messages in thread
From: Alex Williamson @ 2025-07-11 21:00 UTC (permalink / raw)
To: Artem Sadovnikov
Cc: kvm, Yishai Hadas, Jason Gunthorpe, Shameer Kolothum, Kevin Tian,
linux-kernel, lvc-project
On Tue, 1 Jul 2025 14:40:17 +0000
Artem Sadovnikov <a.sadovnikov@ispras.ru> wrote:
> MLX cap pg_track_log_max_msg_size consists of 5 bits, value of which is
> used as power of 2 for max_msg_size. This can lead to multiplication
> overflow between max_msg_size (u32) and integer constant, and afterwards
> incorrect value is being written to rq_size.
>
> Fix this issue by extending integer constant to u64 type.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Suggested-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
> ---
> Changes from v1:
> - The constant type was changed instead of variable type.
> - The patch name was accidentally cut and is now fixed.
> - LKML: https://lore.kernel.org/all/20250629095843.13349-1-a.sadovnikov@ispras.ru/
> ---
> drivers/vfio/pci/mlx5/cmd.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
> index 5b919a0b2524..a92b095b90f6 100644
> --- a/drivers/vfio/pci/mlx5/cmd.c
> +++ b/drivers/vfio/pci/mlx5/cmd.c
> @@ -1523,8 +1523,8 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
> log_max_msg_size = MLX5_CAP_ADV_VIRTUALIZATION(mdev, pg_track_log_max_msg_size);
> max_msg_size = (1ULL << log_max_msg_size);
> /* The RQ must hold at least 4 WQEs/messages for successful QP creation */
> - if (rq_size < 4 * max_msg_size)
> - rq_size = 4 * max_msg_size;
> + if (rq_size < 4ULL * max_msg_size)
> + rq_size = 4ULL * max_msg_size;
>
> memset(tracker, 0, sizeof(*tracker));
> tracker->uar = mlx5_get_uars_page(mdev);
LGTM, Yishai? Thanks,
Alex
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size
2025-07-11 21:00 ` Alex Williamson
@ 2025-07-13 7:56 ` Yishai Hadas
0 siblings, 0 replies; 4+ messages in thread
From: Yishai Hadas @ 2025-07-13 7:56 UTC (permalink / raw)
To: Alex Williamson, Artem Sadovnikov
Cc: kvm, Jason Gunthorpe, Shameer Kolothum, Kevin Tian, linux-kernel,
lvc-project
On 12/07/2025 0:00, Alex Williamson wrote:
> On Tue, 1 Jul 2025 14:40:17 +0000
> Artem Sadovnikov <a.sadovnikov@ispras.ru> wrote:
>
>> MLX cap pg_track_log_max_msg_size consists of 5 bits, value of which is
>> used as power of 2 for max_msg_size. This can lead to multiplication
>> overflow between max_msg_size (u32) and integer constant, and afterwards
>> incorrect value is being written to rq_size.
>>
>> Fix this issue by extending integer constant to u64 type.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
>> Suggested-by: Alex Williamson <alex.williamson@redhat.com>
>> Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
>> ---
>> Changes from v1:
>> - The constant type was changed instead of variable type.
>> - The patch name was accidentally cut and is now fixed.
>> - LKML: https://lore.kernel.org/all/20250629095843.13349-1-a.sadovnikov@ispras.ru/
>> ---
>> drivers/vfio/pci/mlx5/cmd.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
>> index 5b919a0b2524..a92b095b90f6 100644
>> --- a/drivers/vfio/pci/mlx5/cmd.c
>> +++ b/drivers/vfio/pci/mlx5/cmd.c
>> @@ -1523,8 +1523,8 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
>> log_max_msg_size = MLX5_CAP_ADV_VIRTUALIZATION(mdev, pg_track_log_max_msg_size);
>> max_msg_size = (1ULL << log_max_msg_size);
>> /* The RQ must hold at least 4 WQEs/messages for successful QP creation */
>> - if (rq_size < 4 * max_msg_size)
>> - rq_size = 4 * max_msg_size;
>> + if (rq_size < 4ULL * max_msg_size)
>> + rq_size = 4ULL * max_msg_size;
>>
>> memset(tracker, 0, sizeof(*tracker));
>> tracker->uar = mlx5_get_uars_page(mdev);
>
> LGTM, Yishai? Thanks,
>
> Alex
>
Reviewed-by: Yishai Hadas <yishaih@nvidia.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size
2025-07-01 14:40 [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size Artem Sadovnikov
2025-07-11 21:00 ` Alex Williamson
@ 2025-07-16 20:20 ` Alex Williamson
1 sibling, 0 replies; 4+ messages in thread
From: Alex Williamson @ 2025-07-16 20:20 UTC (permalink / raw)
To: Artem Sadovnikov
Cc: kvm, Yishai Hadas, Jason Gunthorpe, Shameer Kolothum, Kevin Tian,
linux-kernel, lvc-project
On Tue, 1 Jul 2025 14:40:17 +0000
Artem Sadovnikov <a.sadovnikov@ispras.ru> wrote:
> MLX cap pg_track_log_max_msg_size consists of 5 bits, value of which is
> used as power of 2 for max_msg_size. This can lead to multiplication
> overflow between max_msg_size (u32) and integer constant, and afterwards
> incorrect value is being written to rq_size.
>
> Fix this issue by extending integer constant to u64 type.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Suggested-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
> ---
> Changes from v1:
> - The constant type was changed instead of variable type.
> - The patch name was accidentally cut and is now fixed.
> - LKML: https://lore.kernel.org/all/20250629095843.13349-1-a.sadovnikov@ispras.ru/
> ---
> drivers/vfio/pci/mlx5/cmd.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
> index 5b919a0b2524..a92b095b90f6 100644
> --- a/drivers/vfio/pci/mlx5/cmd.c
> +++ b/drivers/vfio/pci/mlx5/cmd.c
> @@ -1523,8 +1523,8 @@ int mlx5vf_start_page_tracker(struct vfio_device *vdev,
> log_max_msg_size = MLX5_CAP_ADV_VIRTUALIZATION(mdev, pg_track_log_max_msg_size);
> max_msg_size = (1ULL << log_max_msg_size);
> /* The RQ must hold at least 4 WQEs/messages for successful QP creation */
> - if (rq_size < 4 * max_msg_size)
> - rq_size = 4 * max_msg_size;
> + if (rq_size < 4ULL * max_msg_size)
> + rq_size = 4ULL * max_msg_size;
>
> memset(tracker, 0, sizeof(*tracker));
> tracker->uar = mlx5_get_uars_page(mdev);
Applied to vfio next branch for v6.17. Thanks,
Alex
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-07-01 14:40 [PATCH v2] vfio/mlx5: fix possible overflow in tracking max message size Artem Sadovnikov
2025-07-11 21:00 ` Alex Williamson
2025-07-13 7:56 ` Yishai Hadas
2025-07-16 20:20 ` Alex Williamson
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