[PATCH 2/6] iommu/vt-d: Use virt_to_phys()

[Lu Baolu]

From: Jason Gunthorpe <jgg@xxxxxxxxxx>

If all the inlines are unwound virt_to_dma_pfn() is simply:
   return page_to_pfn(virt_to_page(p)) << (PAGE_SHIFT - VTD_PAGE_SHIFT);

Which can be re-arranged to:
   (page_to_pfn(virt_to_page(p)) << PAGE_SHIFT) >> VTD_PAGE_SHIFT

The only caller is:
   ((uint64_t)virt_to_dma_pfn(tmp_page) << VTD_PAGE_SHIFT)

re-arranged to:
   ((page_to_pfn(virt_to_page(tmp_page)) << PAGE_SHIFT) >> VTD_PAGE_SHIFT)
           << VTD_PAGE_SHIFT

Which simplifies to:
   page_to_pfn(virt_to_page(tmp_page)) << PAGE_SHIFT

That is the same as virt_to_phys(tmp_page), so just remove all of this.

Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Link: https://lore.kernel.org/r/8-v3-e797f4dc6918+93057-iommu_pages_jgg@xxxxxxxxxx
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel/iommu.c |  3 ++-
 drivers/iommu/intel/iommu.h | 19 -------------------
 2 files changed, 2 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 25d31f8c129a..e7152ea77393 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -737,7 +737,8 @@ static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
 				return NULL;
 
 			domain_flush_cache(domain, tmp_page, VTD_PAGE_SIZE);
-			pteval = ((uint64_t)virt_to_dma_pfn(tmp_page) << VTD_PAGE_SHIFT) | DMA_PTE_READ | DMA_PTE_WRITE;
+			pteval = virt_to_phys(tmp_page) | DMA_PTE_READ |
+				 DMA_PTE_WRITE;
 			if (domain->use_first_level)
 				pteval |= DMA_FL_PTE_US | DMA_FL_PTE_ACCESS;
 
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 6ea7bbe26b19..dd980808998d 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -953,25 +953,6 @@ static inline unsigned long lvl_to_nr_pages(unsigned int lvl)
 	return 1UL << min_t(int, (lvl - 1) * LEVEL_STRIDE, MAX_AGAW_PFN_WIDTH);
 }
 
-/* VT-d pages must always be _smaller_ than MM pages. Otherwise things
-   are never going to work. */
-static inline unsigned long mm_to_dma_pfn_start(unsigned long mm_pfn)
-{
-	return mm_pfn << (PAGE_SHIFT - VTD_PAGE_SHIFT);
-}
-static inline unsigned long mm_to_dma_pfn_end(unsigned long mm_pfn)
-{
-	return ((mm_pfn + 1) << (PAGE_SHIFT - VTD_PAGE_SHIFT)) - 1;
-}
-static inline unsigned long page_to_dma_pfn(struct page *pg)
-{
-	return mm_to_dma_pfn_start(page_to_pfn(pg));
-}
-static inline unsigned long virt_to_dma_pfn(void *p)
-{
-	return page_to_dma_pfn(virt_to_page(p));
-}
-
 static inline void context_set_present(struct context_entry *context)
 {
 	context->lo |= 1;
-- 
2.43.0