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SubjectRe: [RFC PATCH 2/2] Removes the x86 dependency on the QAT drivers
From
 > On Wed, 18 May 2022 at 17:55, Andre Przywara <andre.przywara@arm.com> 
wrote:
> >
> > On Tue, 17 May 2022 10:11:09 +0200
> > Ard Biesheuvel <ardb@kernel.org> wrote:
> >
> > Hi,
> >
> > > On Mon, 16 May 2022 at 12:16, <yoan.picchi@arm.com> wrote:
> > > >
> > > > From: Yoan Picchi <yoan.picchi@arm.com>
> > > >
> > > > This dependency looks outdated. After the previous patch, we
have been able
> > > > to use this driver to encrypt some data and to create working
VF on arm64.
> > > >
> > > > Signed-off-by: Yoan Picchi <yoan.picchi@arm.com>
> > >
> > > Are you sure the driver is safe for non-coherent DMA as well?
> >
> > That depends on your definition of "sure".
> > We indeed tested this only on a server with coherent PCIe.
> >
> > I skimmed through the driver, and it looks like to use the DMA API
> > correctly:
> > - I see dma_alloc_coherent() calls for DMA ring buffers.
> > - There are dma_map_single()/dma_unmap_single() pairs in other parts.
> > - Accesses to the BARs are capsuled via macros, using readl/writel.
> > - Access the the SRAM BAR is also only done via those macros.
> >
> > I didn't go through the driver systematically, and of course the
> > interesting parts are the ones you don't see easily, so I am eager
to hear
> > any other opinions on this topic.
> >
> > Ard, do you have anything special in mind? Is there something to
look out
> > for, specifically?
> >
>
> If it uses the DMA api consistently and correctly, and works as
> expected when running under a SMMU, things are probably fine
>
> > The few cards we have access to are in some server in the data
centre, so
> > I can't easily walk in with, say a RockPro64, and test this there.
> >
>
> I suppose this implies that you have tested with SMMUs enabled.

Sorry for the delay, I was away for a few days.
Actually, our previous attempts were with the iommu set to passthrough,
but I
just tested without the passthrough and it works the same way.
>
> > >
> > > > ---
> > > >  drivers/crypto/qat/Kconfig | 14 +++++++-------
> > > >  1 file changed, 7 insertions(+), 7 deletions(-)
> > > >
> > > > diff --git a/drivers/crypto/qat/Kconfig
b/drivers/crypto/qat/Kconfig
> > > > index 4b90c0f22b03..88df2cf4cac9 100644
> > > > --- a/drivers/crypto/qat/Kconfig
> > > > +++ b/drivers/crypto/qat/Kconfig
> > > > @@ -17,7 +17,7 @@ config CRYPTO_DEV_QAT
> > > >
> > > >  config CRYPTO_DEV_QAT_DH895xCC
> > > >         tristate "Support for Intel(R) DH895xCC"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > >           Support for Intel(R) DH895xcc with Intel(R)
QuickAssist Technology
> > > > @@ -28,7 +28,7 @@ config CRYPTO_DEV_QAT_DH895xCC
> > > >
> > > >  config CRYPTO_DEV_QAT_C3XXX
> > > >         tristate "Support for Intel(R) C3XXX"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > >           Support for Intel(R) C3xxx with Intel(R) QuickAssist
Technology
> > > > @@ -39,7 +39,7 @@ config CRYPTO_DEV_QAT_C3XXX
> > > >
> > > >  config CRYPTO_DEV_QAT_C62X
> > > >         tristate "Support for Intel(R) C62X"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > >           Support for Intel(R) C62x with Intel(R) QuickAssist
Technology
> > > > @@ -50,7 +50,7 @@ config CRYPTO_DEV_QAT_C62X
> > > >
> > > >  config CRYPTO_DEV_QAT_4XXX
> > > >         tristate "Support for Intel(R) QAT_4XXX"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > >           Support for Intel(R) QuickAssist Technology QAT_4xxx
> > > > @@ -61,7 +61,7 @@ config CRYPTO_DEV_QAT_4XXX
> > > >
> > > >  config CRYPTO_DEV_QAT_DH895xCCVF
> > > >         tristate "Support for Intel(R) DH895xCC Virtual Function"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select PCI_IOV
> > > >         select CRYPTO_DEV_QAT
> > > >
> > > > @@ -74,7 +74,7 @@ config CRYPTO_DEV_QAT_DH895xCCVF
> > > >
> > > >  config CRYPTO_DEV_QAT_C3XXXVF
> > > >         tristate "Support for Intel(R) C3XXX Virtual Function"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select PCI_IOV
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > > @@ -86,7 +86,7 @@ config CRYPTO_DEV_QAT_C3XXXVF
> > > >
> > > >  config CRYPTO_DEV_QAT_C62XVF
> > > >         tristate "Support for Intel(R) C62X Virtual Function"
> > > > -       depends on X86 && PCI
> > > > +       depends on PCI
> > > >         select PCI_IOV
> > > >         select CRYPTO_DEV_QAT
> > > >         help
> > > > --
> > > > 2.25.1
> > > >
> >

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