vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver

This moves page pinning (get_user_pages_fast()/put_page()) code out of
the platform IOMMU code and puts it to VFIO IOMMU driver where it belongs
to as the platform code does not deal with page pinning.

This makes iommu_take_ownership()/iommu_release_ownership() deal with
the IOMMU table bitmap only.

This removes page unpinning from iommu_take_ownership() as the actual
TCE table might contain garbage and doing put_page() on it is undefined
behaviour.

Besides the last part, the rest of the patch is mechanical.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[aw: for the vfio related changes]
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 0 insertions, 59 deletions

diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index 8353c865db6f..e94a5e3c5a2f 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -194,10 +194,6 @@ extern int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 		unsigned long hwaddr, enum dma_data_direction direction);
 extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
 		unsigned long entry);
-extern int iommu_clear_tces_and_put_pages(struct iommu_table *tbl,
-		unsigned long entry, unsigned long pages);
-extern int iommu_put_tce_user_mode(struct iommu_table *tbl,
-		unsigned long entry, unsigned long tce);
 
 extern void iommu_flush_tce(struct iommu_table *tbl);
 extern int iommu_take_ownership(struct iommu_table *tbl);
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 73eb39a7a9e1..0019c80aa81d 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -986,30 +986,6 @@ unsigned long iommu_clear_tce(struct iommu_table *tbl, unsigned long entry)
 }
 EXPORT_SYMBOL_GPL(iommu_clear_tce);
 
-int iommu_clear_tces_and_put_pages(struct iommu_table *tbl,
-		unsigned long entry, unsigned long pages)
-{
-	unsigned long oldtce;
-	struct page *page;
-
-	for ( ; pages; --pages, ++entry) {
-		oldtce = iommu_clear_tce(tbl, entry);
-		if (!oldtce)
-			continue;
-
-		page = pfn_to_page(oldtce >> PAGE_SHIFT);
-		WARN_ON(!page);
-		if (page) {
-			if (oldtce & TCE_PCI_WRITE)
-				SetPageDirty(page);
-			put_page(page);
-		}
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(iommu_clear_tces_and_put_pages);
-
 /*
  * hwaddr is a kernel virtual address here (0xc... bazillion),
  * tce_build converts it to a physical address.
@@ -1039,35 +1015,6 @@ int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
 }
 EXPORT_SYMBOL_GPL(iommu_tce_build);
 
-int iommu_put_tce_user_mode(struct iommu_table *tbl, unsigned long entry,
-		unsigned long tce)
-{
-	int ret;
-	struct page *page = NULL;
-	unsigned long hwaddr, offset = tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
-	enum dma_data_direction direction = iommu_tce_direction(tce);
-
-	ret = get_user_pages_fast(tce & PAGE_MASK, 1,
-			direction != DMA_TO_DEVICE, &page);
-	if (unlikely(ret != 1)) {
-		/* pr_err("iommu_tce: get_user_pages_fast failed tce=%lx ioba=%lx ret=%d\n",
-				tce, entry << tbl->it_page_shift, ret); */
-		return -EFAULT;
-	}
-	hwaddr = (unsigned long) page_address(page) + offset;
-
-	ret = iommu_tce_build(tbl, entry, hwaddr, direction);
-	if (ret)
-		put_page(page);
-
-	if (ret < 0)
-		pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%d\n",
-			__func__, entry << tbl->it_page_shift, tce, ret);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(iommu_put_tce_user_mode);
-
 int iommu_take_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
@@ -1081,7 +1028,6 @@ int iommu_take_ownership(struct iommu_table *tbl)
 	}
 
 	memset(tbl->it_map, 0xff, sz);
-	iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
 
 	/*
 	 * Disable iommu bypass, otherwise the user can DMA to all of
@@ -1099,7 +1045,6 @@ void iommu_release_ownership(struct iommu_table *tbl)
 {
 	unsigned long sz = (tbl->it_size + 7) >> 3;
 
-	iommu_clear_tces_and_put_pages(tbl, tbl->it_offset, tbl->it_size);
 	memset(tbl->it_map, 0, sz);
 
 	/* Restore bit#0 set by iommu_init_table() */