Hi Joerg,

Thanks a lot for reviewing this patchset.

On 11/27/15 at 12:38pm, Joerg Roedel wrote:
> On Fri, Nov 06, 2015 at 08:10:42PM +0800, Baoquan He wrote:
> > This is v2 draft patch set. It mainly functions as the following steps:
> > 
> > 1. Checking if it's in kdump kernel and previously enabled
> > 2. If yes do below operatons:
> >     a. Do not disable amd iommu and do not touch dev tables before coping 
> > old dev tables
> >     b. Copy dev table from old kernel and set the old domain id in 
> > amd_iommu_pd_alloc_bitmap
> >     c. Copy irq tables from old kernel
> >     d. Copy command buffer and event buffer
> >     e. Don't call update_domain() to set domain->pt_root to dev entries 
> > before device driver initialization.
> >     f. Reset the pre-enabled status in case IOMMU_DMA_OPS of state_next(). 
> > 
> > Existed problems:
> 
> "Existed" means here these problems are gone?

It should be existing, I used wrong word.

> 
> > 
> > 1. It always prints the following message whenever do a flush:
> > 
> >     "AMD-Vi: Completion-Wait loop timed out"
> > 
> > 2. Maybe there's someing wrong with the old irq remapping handling, the 
> > hard disk can't be brought up
> > successfully. You can check the attached kdump kernel boot log with this 
> > patchset applied.
> 
> The reason is most likely that you didn't re-initialize the command
> buffer before doing any flushes. The you see the above Completion-Wait
> loop timeouts.

Yeah, you are right. I tried many kinds of calling, but didn't try
calling iommu_enable_command_buffer() earlier than copy_dev_tables().
Now I tried calling iommu_enable_command_buffer() and
iommu_enable_event_buffer() earlier than copy_dev_tables(), message "AMD-Vi:
Completion-Wait loop timed out" is gone on my AMD IOMMU V1 machine. On
my AMD A10-7850K which is AMD IOMMU V2 it still print that message, I am
debugging.

And problem that sata disk can't be brought up still exist.

Thanks
Baoquan
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