[PATCH 0/2] vhost: fix ranges when call vhost_iotlb_itree_first()

[PATCH 0/2] vhost: fix ranges when call vhost_iotlb_itree_first()

[Stefano Garzarella]

While I was working on vringh to support VA in vringh_*_iotlb()
I saw that the range we use in iotlb_translate() when we call
vhost_iotlb_itree_first() was not correct IIUC.
So I looked at all the calls and found that in vhost.c as well.

I didn't observe a failure and I don't have a reproducer because
I noticed the problem by looking at the code.

Maybe we didn't have a problem, because a shorter range was being
returned anyway and the loop stopped taking into account the total
amount of bytes translated, but I think it's better to fix.

Thanks,
Stefano

Stefano Garzarella (2):
  vringh: fix range used in iotlb_translate()
  vhost: fix range used in translate_desc()

 drivers/vhost/vhost.c  | 4 ++--
 drivers/vhost/vringh.c | 5 ++---
 2 files changed, 4 insertions(+), 5 deletions(-)

-- 
2.38.1

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[PATCH 1/2] vringh: fix range used in iotlb_translate()

[Stefano Garzarella]

vhost_iotlb_itree_first() requires `start` and `last` parameters
to search for a mapping that overlaps the range.

In iotlb_translate() we cyclically call vhost_iotlb_itree_first(),
incrementing `addr` by the amount already translated, so rightly
we move the `start` parameter passed to vhost_iotlb_itree_first(),
but we should hold the `last` parameter constant.

Let's fix it by saving the `last` parameter value before incrementing
`addr` in the loop.

Fixes: 9ad9c49cfe97 ("vringh: IOTLB support")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vhost/vringh.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 11f59dd06a74..828c29306565 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1102,7 +1102,7 @@ static int iotlb_translate(const struct vringh *vrh,
 	struct vhost_iotlb_map *map;
 	struct vhost_iotlb *iotlb = vrh->iotlb;
 	int ret = 0;
-	u64 s = 0;
+	u64 s = 0, last = addr + len - 1;
 
 	spin_lock(vrh->iotlb_lock);
 
@@ -1114,8 +1114,7 @@ static int iotlb_translate(const struct vringh *vrh,
 			break;
 		}
 
-		map = vhost_iotlb_itree_first(iotlb, addr,
-					      addr + len - 1);
+		map = vhost_iotlb_itree_first(iotlb, addr, last);
 		if (!map || map->start > addr) {
 			ret = -EINVAL;
 			break;
-- 
2.38.1

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[PATCH 2/2] vhost: fix range used in translate_desc()

[Stefano Garzarella]

vhost_iotlb_itree_first() requires `start` and `last` parameters
to search for a mapping that overlaps the range.

In translate_desc() we cyclically call vhost_iotlb_itree_first(),
incrementing `addr` by the amount already translated, so rightly
we move the `start` parameter passed to vhost_iotlb_itree_first(),
but we should hold the `last` parameter constant.

Let's fix it by saving the `last` parameter value before incrementing
`addr` in the loop.

Fixes: 0bbe30668d89 ("vhost: factor out IOTLB")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---

I'm not sure about the fixes tag. On the one I used this patch should
apply cleanly, but looking at the latest stable (4.9), maybe we should
use

Fixes: a9709d6874d5 ("vhost: convert pre sorted vhost memory array to interval tree")

Suggestions?
---
 drivers/vhost/vhost.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 40097826cff0..3c2359570df9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2053,7 +2053,7 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 	struct vhost_dev *dev = vq->dev;
 	struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
 	struct iovec *_iov;
-	u64 s = 0;
+	u64 s = 0, last = addr + len - 1;
 	int ret = 0;
 
 	while ((u64)len > s) {
@@ -2063,7 +2063,7 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 			break;
 		}
 
-		map = vhost_iotlb_itree_first(umem, addr, addr + len - 1);
+		map = vhost_iotlb_itree_first(umem, addr, last);
 		if (map == NULL || map->start > addr) {
 			if (umem != dev->iotlb) {
 				ret = -EFAULT;
-- 
2.38.1

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Re: [PATCH 1/2] vringh: fix range used in iotlb_translate()

[Jason Wang]

On Tue, Nov 8, 2022 at 6:34 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> vhost_iotlb_itree_first() requires `start` and `last` parameters
> to search for a mapping that overlaps the range.
>
> In iotlb_translate() we cyclically call vhost_iotlb_itree_first(),
> incrementing `addr` by the amount already translated, so rightly
> we move the `start` parameter passed to vhost_iotlb_itree_first(),
> but we should hold the `last` parameter constant.
>
> Let's fix it by saving the `last` parameter value before incrementing
> `addr` in the loop.
>
> Fixes: 9ad9c49cfe97 ("vringh: IOTLB support")
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

> ---
>  drivers/vhost/vringh.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 11f59dd06a74..828c29306565 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -1102,7 +1102,7 @@ static int iotlb_translate(const struct vringh *vrh,
>         struct vhost_iotlb_map *map;
>         struct vhost_iotlb *iotlb = vrh->iotlb;
>         int ret = 0;
> -       u64 s = 0;
> +       u64 s = 0, last = addr + len - 1;
>
>         spin_lock(vrh->iotlb_lock);
>
> @@ -1114,8 +1114,7 @@ static int iotlb_translate(const struct vringh *vrh,
>                         break;
>                 }
>
> -               map = vhost_iotlb_itree_first(iotlb, addr,
> -                                             addr + len - 1);
> +               map = vhost_iotlb_itree_first(iotlb, addr, last);
>                 if (!map || map->start > addr) {
>                         ret = -EINVAL;
>                         break;
> --
> 2.38.1
>

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Re: [PATCH 2/2] vhost: fix range used in translate_desc()

[Jason Wang]

On Tue, Nov 8, 2022 at 6:34 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> vhost_iotlb_itree_first() requires `start` and `last` parameters
> to search for a mapping that overlaps the range.
>
> In translate_desc() we cyclically call vhost_iotlb_itree_first(),
> incrementing `addr` by the amount already translated, so rightly
> we move the `start` parameter passed to vhost_iotlb_itree_first(),
> but we should hold the `last` parameter constant.
>
> Let's fix it by saving the `last` parameter value before incrementing
> `addr` in the loop.
>
> Fixes: 0bbe30668d89 ("vhost: factor out IOTLB")
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>
> I'm not sure about the fixes tag. On the one I used this patch should
> apply cleanly, but looking at the latest stable (4.9), maybe we should
> use
>
> Fixes: a9709d6874d5 ("vhost: convert pre sorted vhost memory array to interval tree")

I think this should be the right commit to fix.

Other than this

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

>
> Suggestions?
> ---
>  drivers/vhost/vhost.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 40097826cff0..3c2359570df9 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -2053,7 +2053,7 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
>         struct vhost_dev *dev = vq->dev;
>         struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
>         struct iovec *_iov;
> -       u64 s = 0;
> +       u64 s = 0, last = addr + len - 1;
>         int ret = 0;
>
>         while ((u64)len > s) {
> @@ -2063,7 +2063,7 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
>                         break;
>                 }
>
> -               map = vhost_iotlb_itree_first(umem, addr, addr + len - 1);
> +               map = vhost_iotlb_itree_first(umem, addr, last);
>                 if (map == NULL || map->start > addr) {
>                         if (umem != dev->iotlb) {
>                                 ret = -EFAULT;
> --
> 2.38.1
>

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Re: [PATCH 2/2] vhost: fix range used in translate_desc()

[Stefano Garzarella]

On Wed, Nov 09, 2022 at 11:28:41AM +0800, Jason Wang wrote:
>On Tue, Nov 8, 2022 at 6:34 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>>
>> vhost_iotlb_itree_first() requires `start` and `last` parameters
>> to search for a mapping that overlaps the range.
>>
>> In translate_desc() we cyclically call vhost_iotlb_itree_first(),
>> incrementing `addr` by the amount already translated, so rightly
>> we move the `start` parameter passed to vhost_iotlb_itree_first(),
>> but we should hold the `last` parameter constant.
>>
>> Let's fix it by saving the `last` parameter value before incrementing
>> `addr` in the loop.
>>
>> Fixes: 0bbe30668d89 ("vhost: factor out IOTLB")
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>> ---
>>
>> I'm not sure about the fixes tag. On the one I used this patch should
>> apply cleanly, but looking at the latest stable (4.9), maybe we should
>> use
>>
>> Fixes: a9709d6874d5 ("vhost: convert pre sorted vhost memory array to interval tree")
>
>I think this should be the right commit to fix.

Yeah, @Michael should I send a v2 with that tag?

>
>Other than this
>
>Acked-by: Jason Wang <jasowang@redhat.com>
>

Thanks for the review,
Stefano

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Re: [PATCH 2/2] vhost: fix range used in translate_desc()

[Michael S. Tsirkin]

On Wed, Nov 09, 2022 at 09:18:23AM +0100, Stefano Garzarella wrote:
> On Wed, Nov 09, 2022 at 11:28:41AM +0800, Jason Wang wrote:
> > On Tue, Nov 8, 2022 at 6:34 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
> > > 
> > > vhost_iotlb_itree_first() requires `start` and `last` parameters
> > > to search for a mapping that overlaps the range.
> > > 
> > > In translate_desc() we cyclically call vhost_iotlb_itree_first(),
> > > incrementing `addr` by the amount already translated, so rightly
> > > we move the `start` parameter passed to vhost_iotlb_itree_first(),
> > > but we should hold the `last` parameter constant.
> > > 
> > > Let's fix it by saving the `last` parameter value before incrementing
> > > `addr` in the loop.
> > > 
> > > Fixes: 0bbe30668d89 ("vhost: factor out IOTLB")
> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > > ---
> > > 
> > > I'm not sure about the fixes tag. On the one I used this patch should
> > > apply cleanly, but looking at the latest stable (4.9), maybe we should
> > > use
> > > 
> > > Fixes: a9709d6874d5 ("vhost: convert pre sorted vhost memory array to interval tree")
> > 
> > I think this should be the right commit to fix.
> 
> Yeah, @Michael should I send a v2 with that tag?

Pls do.

> > 
> > Other than this
> > 
> > Acked-by: Jason Wang <jasowang@redhat.com>
> > 
> 
> Thanks for the review,
> Stefano

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