* Joerg Roedel <[email protected]> wrote:
> From: Joerg Roedel <[email protected]>
>
> The semaphore used by the AMD IOMMU to signal command
> completion lived on the stack until now, which was safe as
> the driver busy-waited on the semaphore with IRQs disabled,
> so the stack can't go away under the driver.
>
> But the recently introduced vmap-based stacks break this as
> the physical address of the semaphore can't be determinded
> easily anymore. The driver used the __pa() macro, but that
> only works in the direct-mapping. The result were
> Completion-Wait timeout errors seen by the IOMMU driver,
> breaking system boot.
>
> Since putting the semaphore on the stack is bad design
> anyway, move the semaphore into 'struct amd_iommu'. It is
> protected by the per-iommu lock and now in the direct
> mapping again. This fixes the Completion-Wait timeout errors
> and makes AMD IOMMU systems boot again with vmap-based
> stacks enabled.
>
> Reported-by: Borislav Petkov <[email protected]>
> Signed-off-by: Joerg Roedel <[email protected]>
> ---
> drivers/iommu/amd_iommu.c | 14 ++++++++------
> drivers/iommu/amd_iommu_types.h | 2 ++
> 2 files changed, 10 insertions(+), 6 deletions(-)
Cool, thanks! I'll put this into tip:x86/asm which has the virtually mapped
stack
patches - ok?
Thanks,
Ingo
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