Messages in this thread | | | Date | Mon, 26 Oct 2015 12:07:17 -0400 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH] iommu/amd: Fix amd_iommu_detect() (does not fix any issues). |
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On Mon, Aug 31, 2015 at 06:13:03PM -0400, j.glisse@gmail.com wrote: > From: Jérôme Glisse <jglisse@redhat.com> > > Fix amd_iommu_detect() to return positive value on success, like > intended, and not zero. This will not change anything in the end > as AMD IOMMU disable swiotlb and properly associate itself with
Not sure how it disables SWIOTLB? The AMD Vi does not seem to change 'swiotlb'. While 'gart_iommu_init' does. Did you mean the AMD GART code?
> devices even if detect() doesn't return a positive value.
Returning positive will mean that the pci_iommu_alloc will stop processing _all_ other IOMMUs.
While returning 0 will let it detect the other IOMMUs.
Granted on an AMD machine there can be two 'IOMMU's - the GART and the AMD Vi. The detection is always to call gart_iommu_hole_init first, then amd_iommu_detect.
I presume if there was one more type on AMD we would run into trouble.
> > Signed-off-by: Jérôme Glisse <jglisse@redhat.com> > Cc: Joerg Roedel <jroedel@suse.de> > Cc: iommu@lists.linux-foundation.org > --- > drivers/iommu/amd_iommu_init.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c > index a24495e..360a451 100644 > --- a/drivers/iommu/amd_iommu_init.c > +++ b/drivers/iommu/amd_iommu_init.c > @@ -2198,7 +2198,7 @@ int __init amd_iommu_detect(void) > iommu_detected = 1; > x86_init.iommu.iommu_init = amd_iommu_init; > > - return 0; > + return 1; > } > > /**************************************************************************** > -- > 1.8.3.1 > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
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