[PATCH 1/1] drm/radeon drm/amdgpu: fix bad DMA from INTERRUPT_CNTL2

[Sam Bobroff]

On Fri, Nov 15, 2019 at 09:58:18AM -0500, Alex Deucher wrote:
> On Thu, Nov 14, 2019 at 9:05 PM Sam Bobroff <sbobroff at linux.ibm.com> wrote:
> >
> > The INTERRUPT_CNTL2 register expects a valid DMA address, but is
> > currently set with a GPU MC address.  This can cause problems on
> > systems that detect the resulting DMA read from an invalid address
> > (found on a Power8 guest).
> >
> > Instead, use the DMA address of the dummy page because it will always
> > be safe.
> >
> > Fixes: d8f60cfc9345 ("drm/radeon/kms: Add support for interrupts on r6xx/r7xx chips (v3)")
> > Fixes: 25a857fbe973 ("drm/radeon/kms: add support for interrupts on SI")
> > Fixes: a59781bbe528 ("drm/radeon: add support for interrupts on CIK (v5)")
> > Fixes: 27ae10641e9c ("drm/amdgpu: add interupt handler implementation for si v3")
> > Signed-off-by: Sam Bobroff <sbobroff at linux.ibm.com>
> 
> Can you split this into two patches, one for radeon and one for
> amdgpu?  I'll apply them.
> 
> Thanks!
> 
> Alex

No problem at all, I'll post it as v2.

Cheers,
Sam.
> 
> > ---
> > A couple of notes:
> > - Initial discussion:
> >   https://lists.freedesktop.org/archives/dri-devel/2019-November/244090.html
> > - I have only tested the case that uses r600_irq_init(), but they are all very
> >   similar.
> > - I've included a fixes tag for each change, but I don't know if that's the
> >   right thing to do in this case (please feel free to fix them on commit or
> >   whatever).
> >
> > Cheers,
> > Sam.
> >
> >  drivers/gpu/drm/amd/amdgpu/si_ih.c | 3 ++-
> >  drivers/gpu/drm/radeon/cik.c       | 4 ++--
> >  drivers/gpu/drm/radeon/r600.c      | 4 ++--
> >  drivers/gpu/drm/radeon/si.c        | 4 ++--
> >  4 files changed, 8 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/si_ih.c b/drivers/gpu/drm/amd/amdgpu/si_ih.c
> > index 57bb5f9e08b2..88ae27a5a03d 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/si_ih.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/si_ih.c
> > @@ -64,7 +64,8 @@ static int si_ih_irq_init(struct amdgpu_device *adev)
> >         u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
> >
> >         si_ih_disable_interrupts(adev);
> > -       WREG32(INTERRUPT_CNTL2, adev->irq.ih.gpu_addr >> 8);
> > +       /* set dummy read address to dummy page address */
> > +       WREG32(INTERRUPT_CNTL2, adev->dummy_page_addr >> 8);
> >         interrupt_cntl = RREG32(INTERRUPT_CNTL);
> >         interrupt_cntl &= ~IH_DUMMY_RD_OVERRIDE;
> >         interrupt_cntl &= ~IH_REQ_NONSNOOP_EN;
> > diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
> > index 62eab82a64f9..897442754fd0 100644
> > --- a/drivers/gpu/drm/radeon/cik.c
> > +++ b/drivers/gpu/drm/radeon/cik.c
> > @@ -6969,8 +6969,8 @@ static int cik_irq_init(struct radeon_device *rdev)
> >         }
> >
> >         /* setup interrupt control */
> > -       /* XXX this should actually be a bus address, not an MC address. same on older asics */
> > -       WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
> > +       /* set dummy read address to dummy page address */
> > +       WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
> >         interrupt_cntl = RREG32(INTERRUPT_CNTL);
> >         /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
> >          * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
> > diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
> > index e937cc01910d..033bc466a862 100644
> > --- a/drivers/gpu/drm/radeon/r600.c
> > +++ b/drivers/gpu/drm/radeon/r600.c
> > @@ -3696,8 +3696,8 @@ int r600_irq_init(struct radeon_device *rdev)
> >         }
> >
> >         /* setup interrupt control */
> > -       /* set dummy read address to ring address */
> > -       WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
> > +       /* set dummy read address to dummy page address */
> > +       WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
> >         interrupt_cntl = RREG32(INTERRUPT_CNTL);
> >         /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
> >          * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
> > diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> > index 05894d198a79..1d8efb0eefdb 100644
> > --- a/drivers/gpu/drm/radeon/si.c
> > +++ b/drivers/gpu/drm/radeon/si.c
> > @@ -5997,8 +5997,8 @@ static int si_irq_init(struct radeon_device *rdev)
> >         }
> >
> >         /* setup interrupt control */
> > -       /* set dummy read address to ring address */
> > -       WREG32(INTERRUPT_CNTL2, rdev->ih.gpu_addr >> 8);
> > +       /* set dummy read address to dummy page address */
> > +       WREG32(INTERRUPT_CNTL2, rdev->dummy_page.addr >> 8);
> >         interrupt_cntl = RREG32(INTERRUPT_CNTL);
> >         /* IH_DUMMY_RD_OVERRIDE=0 - dummy read disabled with msi, enabled without msi
> >          * IH_DUMMY_RD_OVERRIDE=1 - dummy read controlled by IH_DUMMY_RD_EN
> > --
> > 2.22.0.216.g00a2a96fc9
> >
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