[PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Nate Watterson]

Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
making them unsuitable for use with iommu_domains having an IOMMU_DMA_MSI
cookie since the cookie's iova_domain member, iovad, is uninitialized.

Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
of cookie type, failures are being seen when mapping MSI target
addresses for devices attached to UNMANAGED domains. To work around
this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
initialized to the value returned by cookie_msi_granule().

Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
---
 drivers/iommu/dma-iommu.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8348f366..d7b0816 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
 
 	cookie->msi_iova = base;
 	domain->iova_cookie = cookie;
+
+	/*
+	 * Setup granule for compatibility with __iommu_dma_{alloc/free} and
+	 * add a compile time check to ensure that writing granule won't
+	 * clobber msi_iova.
+	 */
+	cookie->iovad.granule = cookie_msi_granule(cookie);
+	BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
+			sizeof(cookie->msi_iova));
+
 	return 0;
 }
 EXPORT_SYMBOL(iommu_get_msi_cookie);
-- 
Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
Foundation Collaborative Project.

Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Robin Murphy]

Hi Nate,

On 13/04/17 09:55, Nate Watterson wrote:
> Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
> making them unsuitable for use with iommu_domains having an IOMMU_DMA_MSI
> cookie since the cookie's iova_domain member, iovad, is uninitialized.
> 
> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
> of cookie type, failures are being seen when mapping MSI target
> addresses for devices attached to UNMANAGED domains. To work around
> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
> initialized to the value returned by cookie_msi_granule().

Oh bum. Thanks for the report.

However, I really don't like bodging around it with deliberate undefined
behaviour. Fixing things properly doesn't seem too hard:

----->8-----
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8348f366ddd1..62618e77bedc 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
iommu_dma_cookie *cookie,
                dma_addr_t iova, size_t size)
 {
        struct iova_domain *iovad = &cookie->iovad;
-       unsigned long shift = iova_shift(iovad);

        /* The MSI case is only ever cleaning up its most recent
allocation */
        if (cookie->type == IOMMU_DMA_MSI_COOKIE)
                cookie->msi_iova -= size;
        else
-               free_iova_fast(iovad, iova >> shift, size >> shift);
+               free_iova_fast(iovad, iova_pfn(iovad, iova),
+                               size >> iova_shift(iovad));
 }

 static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t
dma_addr,
@@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
*dev, phys_addr_t phys,
 {
        struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
-       struct iova_domain *iovad = &cookie->iovad;
-       size_t iova_off = iova_offset(iovad, phys);
+       size_t iova_off = 0;
        dma_addr_t iova;

-       size = iova_align(iovad, size + iova_off);
+       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
+               iova_off = iova_offset(&cookie->iovad, phys);
+               size = iova_align(&cookie->iovad, size + iova_off);
+       }
+
        iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
        if (!iova)
                return DMA_ERROR_CODE;
-----8<-----

Untested, and you'll probably want to double-check it anyway given that
the original oversight was mine in the first place ;)

Robin.

> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> ---
>  drivers/iommu/dma-iommu.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 8348f366..d7b0816 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
>  
>  	cookie->msi_iova = base;
>  	domain->iova_cookie = cookie;
> +
> +	/*
> +	 * Setup granule for compatibility with __iommu_dma_{alloc/free} and
> +	 * add a compile time check to ensure that writing granule won't
> +	 * clobber msi_iova.
> +	 */
> +	cookie->iovad.granule = cookie_msi_granule(cookie);
> +	BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
> +			sizeof(cookie->msi_iova));
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL(iommu_get_msi_cookie);
> 

Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Shanker Donthineni]

Hi Robin,

I tested your changes and the device pass-through feature works fine on QDF2400 server platform. Maybe Nate comments on the patch contents but it fixes the problem.


@@ -317,13 +317,13 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
                dma_addr_t iova, size_t size)
 {
        struct iova_domain *iovad = &cookie->iovad;
-       unsigned long shift = iova_shift(iovad);

        /* The MSI case is only ever cleaning up its most recent allocation */
        if (cookie->type == IOMMU_DMA_MSI_COOKIE)
                cookie->msi_iova -= size;
        else
-               free_iova_fast(iovad, iova >> shift, size >> shift);
+               free_iova_fast(iovad, iova_pfn(iovad, iova),
+                              size >> iova_shift(iovad));
 }

 static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr,
@@ -538,11 +538,14 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 {
        struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
-       struct iova_domain *iovad = &cookie->iovad;
-       size_t iova_off = iova_offset(iovad, phys);
+       size_t iova_off = 0;
        dma_addr_t iova;

-       size = iova_align(iovad, size + iova_off);
+       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
+               iova_off = iova_offset(&cookie->iovad, phys);
+               size = iova_align(&cookie->iovad, size + iova_off);
+       }


On 04/13/2017 06:21 AM, Robin Murphy wrote:
> Hi Nate,
>
> On 13/04/17 09:55, Nate Watterson wrote:
>> Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
>> making them unsuitable for use with iommu_domains having an IOMMU_DMA_MSI
>> cookie since the cookie's iova_domain member, iovad, is uninitialized.
>>
>> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
>> of cookie type, failures are being seen when mapping MSI target
>> addresses for devices attached to UNMANAGED domains. To work around
>> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
>> initialized to the value returned by cookie_msi_granule().
> Oh bum. Thanks for the report.
>
> However, I really don't like bodging around it with deliberate undefined
> behaviour. Fixing things properly doesn't seem too hard:
>
> ----->8-----
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 8348f366ddd1..62618e77bedc 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
> iommu_dma_cookie *cookie,
>                 dma_addr_t iova, size_t size)
>  {
>         struct iova_domain *iovad = &cookie->iovad;
> -       unsigned long shift = iova_shift(iovad);
>
>         /* The MSI case is only ever cleaning up its most recent
> allocation */
>         if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>                 cookie->msi_iova -= size;
>         else
> -               free_iova_fast(iovad, iova >> shift, size >> shift);
> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
> +                               size >> iova_shift(iovad));
>  }
>
>  static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t
> dma_addr,
> @@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
> *dev, phys_addr_t phys,
>  {
>         struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>         struct iommu_dma_cookie *cookie = domain->iova_cookie;
> -       struct iova_domain *iovad = &cookie->iovad;
> -       size_t iova_off = iova_offset(iovad, phys);
> +       size_t iova_off = 0;
>         dma_addr_t iova;
>
> -       size = iova_align(iovad, size + iova_off);
> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
> +               iova_off = iova_offset(&cookie->iovad, phys);
> +               size = iova_align(&cookie->iovad, size + iova_off);
> +       }
> +
>         iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
>         if (!iova)
>                 return DMA_ERROR_CODE;
> -----8<-----
>
> Untested, and you'll probably want to double-check it anyway given that
> the original oversight was mine in the first place ;)
>
> Robin.
>
>> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
>> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>> ---
>>  drivers/iommu/dma-iommu.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 8348f366..d7b0816 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
>>  
>>  	cookie->msi_iova = base;
>>  	domain->iova_cookie = cookie;
>> +
>> +	/*
>> +	 * Setup granule for compatibility with __iommu_dma_{alloc/free} and
>> +	 * add a compile time check to ensure that writing granule won't
>> +	 * clobber msi_iova.
>> +	 */
>> +	cookie->iovad.granule = cookie_msi_granule(cookie);
>> +	BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
>> +			sizeof(cookie->msi_iova));
>> +
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL(iommu_get_msi_cookie);
>>

-- 
Shanker Donthineni
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

RE: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Bharat Bhushan]

Hi Robin,

I faced same issue on our platform and debugged to get the root cause of the issue. Also fixed in somewhat similar way, cleared iova_off and not change size for if cookie->type is  IOMMU_DMA_MSI_COOKIE. Anyways that was not as good as below changes.

While just now I saw this was already discussed and solved. Should have looked earlier to save time, but the debugging was some learning experience 😊 

I have tested your below change and it works fine on NXP platform.

Thanks
-Bharat

> -----Original Message-----
> From: iommu-bounces@lists.linux-foundation.org [mailto:iommu-
> bounces@lists.linux-foundation.org] On Behalf Of Shanker Donthineni
> Sent: Thursday, April 13, 2017 8:00 PM
> To: Robin Murphy <robin.murphy@arm.com>; Nate Watterson
> <nwatters@codeaurora.org>; Joerg Roedel <joro@8bytes.org>;
> iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] iommu/dma: Setup iova_domain granule for
> IOMMU_DMA_MSI cookies
> 
> Hi Robin,
> 
> I tested your changes and the device pass-through feature works fine on
> QDF2400 server platform. Maybe Nate comments on the patch contents but
> it fixes the problem.
> 
> 
> @@ -317,13 +317,13 @@ static void iommu_dma_free_iova(struct
> iommu_dma_cookie *cookie,
>                 dma_addr_t iova, size_t size)  {
>         struct iova_domain *iovad = &cookie->iovad;
> -       unsigned long shift = iova_shift(iovad);
> 
>         /* The MSI case is only ever cleaning up its most recent allocation */
>         if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>                 cookie->msi_iova -= size;
>         else
> -               free_iova_fast(iovad, iova >> shift, size >> shift);
> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
> +                              size >> iova_shift(iovad));
>  }
> 
>  static void __iommu_dma_unmap(struct iommu_domain *domain,
> dma_addr_t dma_addr, @@ -538,11 +538,14 @@ static dma_addr_t
> __iommu_dma_map(struct device *dev, phys_addr_t phys,  {
>         struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>         struct iommu_dma_cookie *cookie = domain->iova_cookie;
> -       struct iova_domain *iovad = &cookie->iovad;
> -       size_t iova_off = iova_offset(iovad, phys);
> +       size_t iova_off = 0;
>         dma_addr_t iova;
> 
> -       size = iova_align(iovad, size + iova_off);
> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
> +               iova_off = iova_offset(&cookie->iovad, phys);
> +               size = iova_align(&cookie->iovad, size + iova_off);
> +       }
> 
> 
> On 04/13/2017 06:21 AM, Robin Murphy wrote:
> > Hi Nate,
> >
> > On 13/04/17 09:55, Nate Watterson wrote:
> >> Currently, the __iommu_dma_{map/free} functions call
> >> iova_{offset/align} making them unsuitable for use with iommu_domains
> >> having an IOMMU_DMA_MSI cookie since the cookie's iova_domain
> member, iovad, is uninitialized.
> >>
> >> Now that iommu_dma_get_msi_page() calls __iommu_dma_map()
> regardless
> >> of cookie type, failures are being seen when mapping MSI target
> >> addresses for devices attached to UNMANAGED domains. To work
> around
> >> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
> >> initialized to the value returned by cookie_msi_granule().
> > Oh bum. Thanks for the report.
> >
> > However, I really don't like bodging around it with deliberate
> > undefined behaviour. Fixing things properly doesn't seem too hard:
> >
> > ----->8-----
> > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> > index 8348f366ddd1..62618e77bedc 100644
> > --- a/drivers/iommu/dma-iommu.c
> > +++ b/drivers/iommu/dma-iommu.c
> > @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
> > iommu_dma_cookie *cookie,
> >                 dma_addr_t iova, size_t size)  {
> >         struct iova_domain *iovad = &cookie->iovad;
> > -       unsigned long shift = iova_shift(iovad);
> >
> >         /* The MSI case is only ever cleaning up its most recent
> > allocation */
> >         if (cookie->type == IOMMU_DMA_MSI_COOKIE)
> >                 cookie->msi_iova -= size;
> >         else
> > -               free_iova_fast(iovad, iova >> shift, size >> shift);
> > +               free_iova_fast(iovad, iova_pfn(iovad, iova),
> > +                               size >> iova_shift(iovad));
> >  }
> >
> >  static void __iommu_dma_unmap(struct iommu_domain *domain,
> dma_addr_t
> > dma_addr, @@ -617,11 +617,14 @@ static dma_addr_t
> > __iommu_dma_map(struct device *dev, phys_addr_t phys,  {
> >         struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> >         struct iommu_dma_cookie *cookie = domain->iova_cookie;
> > -       struct iova_domain *iovad = &cookie->iovad;
> > -       size_t iova_off = iova_offset(iovad, phys);
> > +       size_t iova_off = 0;
> >         dma_addr_t iova;
> >
> > -       size = iova_align(iovad, size + iova_off);
> > +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
> > +               iova_off = iova_offset(&cookie->iovad, phys);
> > +               size = iova_align(&cookie->iovad, size + iova_off);
> > +       }
> > +
> >         iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev),
> dev);
> >         if (!iova)
> >                 return DMA_ERROR_CODE;
> > -----8<-----
> >
> > Untested, and you'll probably want to double-check it anyway given
> > that the original oversight was mine in the first place ;)
> >
> > Robin.
> >
> >> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
> >> Signed-off-by: Nate Watterson <nwatters@codeaurora.org>
> >> ---
> >>  drivers/iommu/dma-iommu.c | 10 ++++++++++
> >>  1 file changed, 10 insertions(+)
> >>
> >> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> >> index 8348f366..d7b0816 100644
> >> --- a/drivers/iommu/dma-iommu.c
> >> +++ b/drivers/iommu/dma-iommu.c
> >> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct
> iommu_domain
> >> *domain, dma_addr_t base)
> >>
> >>  	cookie->msi_iova = base;
> >>  	domain->iova_cookie = cookie;
> >> +
> >> +	/*
> >> +	 * Setup granule for compatibility with __iommu_dma_{alloc/free}
> and
> >> +	 * add a compile time check to ensure that writing granule won't
> >> +	 * clobber msi_iova.
> >> +	 */
> >> +	cookie->iovad.granule = cookie_msi_granule(cookie);
> >> +	BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
> >> +			sizeof(cookie->msi_iova));
> >> +
> >>  	return 0;
> >>  }
> >>  EXPORT_SYMBOL(iommu_get_msi_cookie);
> >>
> 
> --
> Shanker Donthineni
> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
> Technologies, Inc.
> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
> Foundation Collaborative Project.
> 
> _______________________________________________
> iommu mailing list
> iommu@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
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Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Nate Watterson]

Hi Robin,

On 4/13/2017 7:21 AM, Robin Murphy wrote:
> Hi Nate,
> 
> On 13/04/17 09:55, Nate Watterson wrote:
>> Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
>> making them unsuitable for use with iommu_domains having an IOMMU_DMA_MSI
>> cookie since the cookie's iova_domain member, iovad, is uninitialized.
>>
>> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
>> of cookie type, failures are being seen when mapping MSI target
>> addresses for devices attached to UNMANAGED domains. To work around
>> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
>> initialized to the value returned by cookie_msi_granule().
> 
> Oh bum. Thanks for the report.
> 
> However, I really don't like bodging around it with deliberate undefined
> behaviour. Fixing things properly doesn't seem too hard:

I was not especially please with my solution, but I wanted to avoid
potentially missing any other spots in the code where granule was
used uninitialized. The compile time check made me feel a little
less dirty about innappropriately using the iova_domain with MSI
cookies.

> 
> ----->8-----
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 8348f366ddd1..62618e77bedc 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
> iommu_dma_cookie *cookie,
>                  dma_addr_t iova, size_t size)
>   {
>          struct iova_domain *iovad = &cookie->iovad;
> -       unsigned long shift = iova_shift(iovad);
> 
>          /* The MSI case is only ever cleaning up its most recent
> allocation */
>          if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>                  cookie->msi_iova -= size;
>          else
> -               free_iova_fast(iovad, iova >> shift, size >> shift);
> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
> +                               size >> iova_shift(iovad));
>   }
> 
>   static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t
> dma_addr,
> @@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
> *dev, phys_addr_t phys,
>   {
>          struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>          struct iommu_dma_cookie *cookie = domain->iova_cookie;
> -       struct iova_domain *iovad = &cookie->iovad;
> -       size_t iova_off = iova_offset(iovad, phys);
> +       size_t iova_off = 0;
>          dma_addr_t iova;
> 
> -       size = iova_align(iovad, size + iova_off);
> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
> +               iova_off = iova_offset(&cookie->iovad, phys);
> +               size = iova_align(&cookie->iovad, size + iova_off);
> +       }
> +
>          iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
>          if (!iova)
>                  return DMA_ERROR_CODE;
> -----8<-----
> 
> Untested, and you'll probably want to double-check it anyway given that
> the original oversight was mine in the first place ;)

This looks good to me. As Shanker has already mentioned, it does fix the
faults we were previously seeing with direct device assignment. I also
verified that there aren't any other obvious cases of a granule == 0
being used in the dma_iommu code by adding BUG_ON(!iovad->granule) to
iova_{mask/align/offset/...} and running a variety of tests without
issue.

Are you going to post the patch?

> 
> Robin.
> 
>> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
>> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>> ---
>>   drivers/iommu/dma-iommu.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 8348f366..d7b0816 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
>>   
>>   	cookie->msi_iova = base;
>>   	domain->iova_cookie = cookie;
>> +
>> +	/*
>> +	 * Setup granule for compatibility with __iommu_dma_{alloc/free} and
>> +	 * add a compile time check to ensure that writing granule won't
>> +	 * clobber msi_iova.
>> +	 */
>> +	cookie->iovad.granule = cookie_msi_granule(cookie);
>> +	BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
>> +			sizeof(cookie->msi_iova));
>> +
>>   	return 0;
>>   }
>>   EXPORT_SYMBOL(iommu_get_msi_cookie);
>>
> 
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Auger Eric]

Hi,

On 13/04/2017 21:38, Nate Watterson wrote:
> Hi Robin,
> 
> On 4/13/2017 7:21 AM, Robin Murphy wrote:
>> Hi Nate,
>>
>> On 13/04/17 09:55, Nate Watterson wrote:
>>> Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
>>> making them unsuitable for use with iommu_domains having an
>>> IOMMU_DMA_MSI
>>> cookie since the cookie's iova_domain member, iovad, is uninitialized.
>>>
>>> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
>>> of cookie type, failures are being seen when mapping MSI target
>>> addresses for devices attached to UNMANAGED domains. To work around
>>> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
>>> initialized to the value returned by cookie_msi_granule().
>>
>> Oh bum. Thanks for the report.
>>
>> However, I really don't like bodging around it with deliberate undefined
>> behaviour. Fixing things properly doesn't seem too hard:
> 
> I was not especially please with my solution, but I wanted to avoid
> potentially missing any other spots in the code where granule was
> used uninitialized. The compile time check made me feel a little
> less dirty about innappropriately using the iova_domain with MSI
> cookies.
> 
>>
>> ----->8-----
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 8348f366ddd1..62618e77bedc 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
>> iommu_dma_cookie *cookie,
>>                  dma_addr_t iova, size_t size)
>>   {
>>          struct iova_domain *iovad = &cookie->iovad;
>> -       unsigned long shift = iova_shift(iovad);
>>
>>          /* The MSI case is only ever cleaning up its most recent
>> allocation */
>>          if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>>                  cookie->msi_iova -= size;
>>          else
>> -               free_iova_fast(iovad, iova >> shift, size >> shift);
>> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
>> +                               size >> iova_shift(iovad));
>>   }
>>
>>   static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t
>> dma_addr,
>> @@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
>> *dev, phys_addr_t phys,
>>   {
>>          struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>>          struct iommu_dma_cookie *cookie = domain->iova_cookie;
>> -       struct iova_domain *iovad = &cookie->iovad;
>> -       size_t iova_off = iova_offset(iovad, phys);
>> +       size_t iova_off = 0;
>>          dma_addr_t iova;
>>
>> -       size = iova_align(iovad, size + iova_off);
>> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
>> +               iova_off = iova_offset(&cookie->iovad, phys);
>> +               size = iova_align(&cookie->iovad, size + iova_off);
>> +       }
>> +
>>          iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev),
>> dev);
>>          if (!iova)
>>                  return DMA_ERROR_CODE;
>> -----8<-----
>>
>> Untested, and you'll probably want to double-check it anyway given that
>> the original oversight was mine in the first place ;)
> 
> This looks good to me. As Shanker has already mentioned, it does fix the
> faults we were previously seeing with direct device assignment. I also
> verified that there aren't any other obvious cases of a granule == 0
> being used in the dma_iommu code by adding BUG_ON(!iovad->granule) to
> iova_{mask/align/offset/...} and running a variety of tests without
> issue.
> 
> Are you going to post the patch?

I also noticed PCIe passthrough/ARM is broken for me with 4.12-r1. I
tested Robin's patch as well, on Cavium ThunderX, and this fixes the
faults I have seen.

Has anyone sent a formal patch?

Thanks

Eric

> 
>>
>> Robin.
>>
>>> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
>>> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>>> ---
>>>   drivers/iommu/dma-iommu.c | 10 ++++++++++
>>>   1 file changed, 10 insertions(+)
>>>
>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>> index 8348f366..d7b0816 100644
>>> --- a/drivers/iommu/dma-iommu.c
>>> +++ b/drivers/iommu/dma-iommu.c
>>> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain
>>> *domain, dma_addr_t base)
>>>         cookie->msi_iova = base;
>>>       domain->iova_cookie = cookie;
>>> +
>>> +    /*
>>> +     * Setup granule for compatibility with __iommu_dma_{alloc/free}
>>> and
>>> +     * add a compile time check to ensure that writing granule won't
>>> +     * clobber msi_iova.
>>> +     */
>>> +    cookie->iovad.granule = cookie_msi_granule(cookie);
>>> +    BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
>>> +            sizeof(cookie->msi_iova));
>>> +
>>>       return 0;
>>>   }
>>>   EXPORT_SYMBOL(iommu_get_msi_cookie);
>>>
>>

Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Nate Watterson]

On 5/16/2017 3:55 PM, Auger Eric wrote:
> Hi,
> 
> On 13/04/2017 21:38, Nate Watterson wrote:
>> Hi Robin,
>>
>> On 4/13/2017 7:21 AM, Robin Murphy wrote:
>>> Hi Nate,
>>>
>>> On 13/04/17 09:55, Nate Watterson wrote:
>>>> Currently, the __iommu_dma_{map/free} functions call iova_{offset/align}
>>>> making them unsuitable for use with iommu_domains having an
>>>> IOMMU_DMA_MSI
>>>> cookie since the cookie's iova_domain member, iovad, is uninitialized.
>>>>
>>>> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
>>>> of cookie type, failures are being seen when mapping MSI target
>>>> addresses for devices attached to UNMANAGED domains. To work around
>>>> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
>>>> initialized to the value returned by cookie_msi_granule().
>>>
>>> Oh bum. Thanks for the report.
>>>
>>> However, I really don't like bodging around it with deliberate undefined
>>> behaviour. Fixing things properly doesn't seem too hard:
>>
>> I was not especially please with my solution, but I wanted to avoid
>> potentially missing any other spots in the code where granule was
>> used uninitialized. The compile time check made me feel a little
>> less dirty about innappropriately using the iova_domain with MSI
>> cookies.
>>
>>>
>>> ----->8-----
>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>> index 8348f366ddd1..62618e77bedc 100644
>>> --- a/drivers/iommu/dma-iommu.c
>>> +++ b/drivers/iommu/dma-iommu.c
>>> @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
>>> iommu_dma_cookie *cookie,
>>>                   dma_addr_t iova, size_t size)
>>>    {
>>>           struct iova_domain *iovad = &cookie->iovad;
>>> -       unsigned long shift = iova_shift(iovad);
>>>
>>>           /* The MSI case is only ever cleaning up its most recent
>>> allocation */
>>>           if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>>>                   cookie->msi_iova -= size;
>>>           else
>>> -               free_iova_fast(iovad, iova >> shift, size >> shift);
>>> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
>>> +                               size >> iova_shift(iovad));
>>>    }
>>>
>>>    static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t
>>> dma_addr,
>>> @@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
>>> *dev, phys_addr_t phys,
>>>    {
>>>           struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>>>           struct iommu_dma_cookie *cookie = domain->iova_cookie;
>>> -       struct iova_domain *iovad = &cookie->iovad;
>>> -       size_t iova_off = iova_offset(iovad, phys);
>>> +       size_t iova_off = 0;
>>>           dma_addr_t iova;
>>>
>>> -       size = iova_align(iovad, size + iova_off);
>>> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
>>> +               iova_off = iova_offset(&cookie->iovad, phys);
>>> +               size = iova_align(&cookie->iovad, size + iova_off);
>>> +       }
>>> +
>>>           iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev),
>>> dev);
>>>           if (!iova)
>>>                   return DMA_ERROR_CODE;
>>> -----8<-----
>>>
>>> Untested, and you'll probably want to double-check it anyway given that
>>> the original oversight was mine in the first place ;)
>>
>> This looks good to me. As Shanker has already mentioned, it does fix the
>> faults we were previously seeing with direct device assignment. I also
>> verified that there aren't any other obvious cases of a granule == 0
>> being used in the dma_iommu code by adding BUG_ON(!iovad->granule) to
>> iova_{mask/align/offset/...} and running a variety of tests without
>> issue.
>>
>> Are you going to post the patch?
> 
> I also noticed PCIe passthrough/ARM is broken for me with 4.12-r1. I
> tested Robin's patch as well, on Cavium ThunderX, and this fixes the
> faults I have seen.
> 
> Has anyone sent a formal patch?

iommu/dma: Don't touch invalid iova_domain members

> 
> Thanks
> 
> Eric
> 
>>
>>>
>>> Robin.
>>>
>>>> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
>>>> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>>>> ---
>>>>    drivers/iommu/dma-iommu.c | 10 ++++++++++
>>>>    1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>>> index 8348f366..d7b0816 100644
>>>> --- a/drivers/iommu/dma-iommu.c
>>>> +++ b/drivers/iommu/dma-iommu.c
>>>> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain
>>>> *domain, dma_addr_t base)
>>>>          cookie->msi_iova = base;
>>>>        domain->iova_cookie = cookie;
>>>> +
>>>> +    /*
>>>> +     * Setup granule for compatibility with __iommu_dma_{alloc/free}
>>>> and
>>>> +     * add a compile time check to ensure that writing granule won't
>>>> +     * clobber msi_iova.
>>>> +     */
>>>> +    cookie->iovad.granule = cookie_msi_granule(cookie);
>>>> +    BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
>>>> +            sizeof(cookie->msi_iova));
>>>> +
>>>>        return 0;
>>>>    }
>>>>    EXPORT_SYMBOL(iommu_get_msi_cookie);
>>>>
>>>

-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH] iommu/dma: Setup iova_domain granule for IOMMU_DMA_MSI cookies

[Auger Eric]

Hi Nate,

On 16/05/2017 22:07, Nate Watterson wrote:
> 
> 
> On 5/16/2017 3:55 PM, Auger Eric wrote:
>> Hi,
>>
>> On 13/04/2017 21:38, Nate Watterson wrote:
>>> Hi Robin,
>>>
>>> On 4/13/2017 7:21 AM, Robin Murphy wrote:
>>>> Hi Nate,
>>>>
>>>> On 13/04/17 09:55, Nate Watterson wrote:
>>>>> Currently, the __iommu_dma_{map/free} functions call
>>>>> iova_{offset/align}
>>>>> making them unsuitable for use with iommu_domains having an
>>>>> IOMMU_DMA_MSI
>>>>> cookie since the cookie's iova_domain member, iovad, is uninitialized.
>>>>>
>>>>> Now that iommu_dma_get_msi_page() calls __iommu_dma_map() regardless
>>>>> of cookie type, failures are being seen when mapping MSI target
>>>>> addresses for devices attached to UNMANAGED domains. To work around
>>>>> this issue, the iova_domain granule for IOMMU_DMA_MSI cookies is
>>>>> initialized to the value returned by cookie_msi_granule().
>>>>
>>>> Oh bum. Thanks for the report.
>>>>
>>>> However, I really don't like bodging around it with deliberate
>>>> undefined
>>>> behaviour. Fixing things properly doesn't seem too hard:
>>>
>>> I was not especially please with my solution, but I wanted to avoid
>>> potentially missing any other spots in the code where granule was
>>> used uninitialized. The compile time check made me feel a little
>>> less dirty about innappropriately using the iova_domain with MSI
>>> cookies.
>>>
>>>>
>>>> ----->8-----
>>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>>> index 8348f366ddd1..62618e77bedc 100644
>>>> --- a/drivers/iommu/dma-iommu.c
>>>> +++ b/drivers/iommu/dma-iommu.c
>>>> @@ -396,13 +396,13 @@ static void iommu_dma_free_iova(struct
>>>> iommu_dma_cookie *cookie,
>>>>                   dma_addr_t iova, size_t size)
>>>>    {
>>>>           struct iova_domain *iovad = &cookie->iovad;
>>>> -       unsigned long shift = iova_shift(iovad);
>>>>
>>>>           /* The MSI case is only ever cleaning up its most recent
>>>> allocation */
>>>>           if (cookie->type == IOMMU_DMA_MSI_COOKIE)
>>>>                   cookie->msi_iova -= size;
>>>>           else
>>>> -               free_iova_fast(iovad, iova >> shift, size >> shift);
>>>> +               free_iova_fast(iovad, iova_pfn(iovad, iova),
>>>> +                               size >> iova_shift(iovad));
>>>>    }
>>>>
>>>>    static void __iommu_dma_unmap(struct iommu_domain *domain,
>>>> dma_addr_t
>>>> dma_addr,
>>>> @@ -617,11 +617,14 @@ static dma_addr_t __iommu_dma_map(struct device
>>>> *dev, phys_addr_t phys,
>>>>    {
>>>>           struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>>>>           struct iommu_dma_cookie *cookie = domain->iova_cookie;
>>>> -       struct iova_domain *iovad = &cookie->iovad;
>>>> -       size_t iova_off = iova_offset(iovad, phys);
>>>> +       size_t iova_off = 0;
>>>>           dma_addr_t iova;
>>>>
>>>> -       size = iova_align(iovad, size + iova_off);
>>>> +       if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
>>>> +               iova_off = iova_offset(&cookie->iovad, phys);
>>>> +               size = iova_align(&cookie->iovad, size + iova_off);
>>>> +       }
>>>> +
>>>>           iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev),
>>>> dev);
>>>>           if (!iova)
>>>>                   return DMA_ERROR_CODE;
>>>> -----8<-----
>>>>
>>>> Untested, and you'll probably want to double-check it anyway given that
>>>> the original oversight was mine in the first place ;)
>>>
>>> This looks good to me. As Shanker has already mentioned, it does fix the
>>> faults we were previously seeing with direct device assignment. I also
>>> verified that there aren't any other obvious cases of a granule == 0
>>> being used in the dma_iommu code by adding BUG_ON(!iovad->granule) to
>>> iova_{mask/align/offset/...} and running a variety of tests without
>>> issue.
>>>
>>> Are you going to post the patch?
>>
>> I also noticed PCIe passthrough/ARM is broken for me with 4.12-r1. I
>> tested Robin's patch as well, on Cavium ThunderX, and this fixes the
>> faults I have seen.
>>
>> Has anyone sent a formal patch?
> 
> iommu/dma: Don't touch invalid iova_domain members

thanks!

Best Regards

Eric
> 
>>
>> Thanks
>>
>> Eric
>>
>>>
>>>>
>>>> Robin.
>>>>
>>>>> Fixes: a44e6657585b ("iommu/dma: Clean up MSI IOVA allocation")
>>>>> Signed-off-by: Nate Watterson <nwatters-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
>>>>> ---
>>>>>    drivers/iommu/dma-iommu.c | 10 ++++++++++
>>>>>    1 file changed, 10 insertions(+)
>>>>>
>>>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>>>> index 8348f366..d7b0816 100644
>>>>> --- a/drivers/iommu/dma-iommu.c
>>>>> +++ b/drivers/iommu/dma-iommu.c
>>>>> @@ -127,6 +127,16 @@ int iommu_get_msi_cookie(struct iommu_domain
>>>>> *domain, dma_addr_t base)
>>>>>          cookie->msi_iova = base;
>>>>>        domain->iova_cookie = cookie;
>>>>> +
>>>>> +    /*
>>>>> +     * Setup granule for compatibility with __iommu_dma_{alloc/free}
>>>>> and
>>>>> +     * add a compile time check to ensure that writing granule won't
>>>>> +     * clobber msi_iova.
>>>>> +     */
>>>>> +    cookie->iovad.granule = cookie_msi_granule(cookie);
>>>>> +    BUILD_BUG_ON(offsetof(struct iova_domain, granule) <
>>>>> +            sizeof(cookie->msi_iova));
>>>>> +
>>>>>        return 0;
>>>>>    }
>>>>>    EXPORT_SYMBOL(iommu_get_msi_cookie);
>>>>>
>>>>
>