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vfio/type1: Remove map_try_harder() code path 

The AMD IOMMU driver can now map a huge-page where smaller
mappings existed before, so this code-path is no longer
triggered.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2018-11-09 12:07:12 +01:00
parent 6f820bb995
commit 7a30423a95
1 changed files with 2 additions and 31 deletions
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33
drivers/vfio/vfio_iommu_type1.c
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@ -978,32 +978,6 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
return ret;
}
/*
* Turns out AMD IOMMU has a page table bug where it won't map large pages
* to a region that previously mapped smaller pages. This should be fixed
* soon, so this is just a temporary workaround to break mappings down into
* PAGE_SIZE. Better to map smaller pages than nothing.
*/
static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
unsigned long pfn, long npage, int prot)
{
long i;
int ret = 0;
for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
ret = iommu_map(domain->domain, iova,
(phys_addr_t)pfn << PAGE_SHIFT,
PAGE_SIZE, prot | domain->prot);
if (ret)
break;
}
for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
iommu_unmap(domain->domain, iova, PAGE_SIZE);
return ret;
}
static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
unsigned long pfn, long npage, int prot)
{
@ -1013,11 +987,8 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
list_for_each_entry(d, &iommu->domain_list, next) {
ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
npage << PAGE_SHIFT, prot | d->prot);
if (ret) {
if (ret != -EBUSY ||
map_try_harder(d, iova, pfn, npage, prot))
goto unwind;
}
if (ret)
goto unwind;
cond_resched();
}