[PATCH 3/4] Bug Fix drivers/pci/intel-iommu.c: convert paddr to correct DMA pfn

[PATCH 3/4] Bug Fix drivers/pci/intel-iommu.c: convert paddr to correct DMA pfn

[Fenghua Yu]

When calling domain_pfn_mapping(), paddr should be converted to DMA pfn
correctly instead just shift by VTD_PAGE_SHIFT.

This issue causes kernel panic on PAGE_SIZE>VTD_PAGE_SIZE platforms e.g. ia64
platforms.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

---

 drivers/pci/intel-iommu.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index bec29ed..54ee63d 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2558,6 +2564,7 @@ static dma_addr_t __intel_map_single(struct device *hwdev, phys_addr_t paddr,
 	int prot = 0;
 	int ret;
 	struct intel_iommu *iommu;
+	unsigned long paddr_pfn = paddr >> PAGE_SHIFT;
 
 	BUG_ON(dir == DMA_NONE);
 
@@ -2592,7 +2599,7 @@ static dma_addr_t __intel_map_single(struct device *hwdev, phys_addr_t paddr,
 	 * is not a big problem
 	 */
 	ret = domain_pfn_mapping(domain, mm_to_dma_pfn(iova->pfn_lo),
-				 paddr >> VTD_PAGE_SHIFT, size, prot);
+				 mm_to_dma_pfn(paddr_pfn), size, prot);
 	if (ret)
 		goto error;
 

Re: [PATCH 3/4] Bug Fix drivers/pci/intel-iommu.c: convert paddr to correct DMA pfn

[David Woodhouse]

On Tue, 2009-08-04 at 15:10 -0700, Fenghua Yu wrote:
> When calling domain_pfn_mapping(), paddr should be converted to DMA pfn
> correctly instead just shift by VTD_PAGE_SHIFT.
> 
> This issue causes kernel panic on PAGE_SIZE>VTD_PAGE_SIZE platforms e.g. ia64
> platforms.
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

Using the word 'alignment' somewhere in the above commit would have
confused me a lot less -- I got most of the way through composing a mail
asking how this patch wasn't a no-op, before I spotted it.

An alternative would be to align the size to DMA pages? Would that make
the sg case easier? 

(Thanks for fixing this, btw)

-- 
dwmw2

[PATCH 4/4] Bug Fix drivers/pci/intel-iommu.c: convert pfn_lo to VTD page address when calling iommu_flush_dev_iotlb()

[Fenghua Yu]

The iova->pfn_lo should be converted to VTD page address before it's passed to
iommu_flush_dev_iotlb().

This issue may cause DMA failure on PAGE_SIZE>VTD_PAGE_SIZE platforms e.g. ia64
platforms.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

---

 drivers/pci/intel-iommu.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index bec29ed..54ee63d 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2647,7 +2654,7 @@ static void flush_unmaps(void)
 			mask = (iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT;
 			mask = ilog2(mask >> VTD_PAGE_SHIFT);
 			iommu_flush_dev_iotlb(deferred_flush[i].domain[j],
-					iova->pfn_lo << PAGE_SHIFT, mask);
+					iova->pfn_lo << VTD_PAGE_SHIFT, mask);
 			__free_iova(&deferred_flush[i].domain[j]->iovad, iova);
 		}
 		deferred_flush[i].next = 0;

Re: [PATCH 4/4] Bug Fix drivers/pci/intel-iommu.c: convert pfn_lo to VTD page address when calling iommu_flush_dev_iotlb()

[David Woodhouse]

On Tue, 2009-08-04 at 15:11 -0700, Fenghua Yu wrote:
> The iova->pfn_lo should be converted to VTD page address before it's passed to
> iommu_flush_dev_iotlb().
> 
> This issue may cause DMA failure on PAGE_SIZE>VTD_PAGE_SIZE platforms e.g. ia64
> platforms.
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

I think this one is wrong. We allocate IOVA space in MM pages, not DMA
pages -- so the pfn_lo is an MM page already, and shifting by PAGE_SHIFT
is the right thing to do.

(I could be tempted to allocate it in DMA pages instead, but that's a
different story).

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation

[PATCH] linux-next drm_cache.c: fix compilation error

[Fenghua Yu]

When compiling drm_cache.c on ia64, gcc reports undefined
drm_clflush_ipi_handler() error. The problem is because drm_cache_ipi_handler is
a typo.

One straightforward fix is changing drm_cache_ipi_handler to
drm_clflush_ipi_handler.

But since drm_clflush_ipi_handler() does nothing on non-x86 platforms and ipi
handling is costly, it would be better to just do nothing on non-x86 platforms
and remove drm_clflush_ipi_handler() for those platforms.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

---
The issue was introduced by commit c9c97b8c75019814d8c007059bc827bb475be917
in linux-next.

 drm_cache.c |    7 -------
 1 files changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 3a5575e..8054a5c 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -62,10 +62,6 @@ drm_clflush_ipi_handler(void *null)
 {
 	wbinvd();
 }
-#elif !defined(__powerpc__)
-static void drm_cache_ipi_handler(void *dummy)
-{
-}
 #endif
 void
 drm_clflush_pages(struct page *pages[], unsigned long num_pages)
@@ -94,9 +90,6 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
 				   (unsigned long)page_virtual + PAGE_SIZE);
 		kunmap_atomic(page_virtual, KM_USER0);
 	}
-#else
-	if (on_each_cpu(drm_clflush_ipi_handler, NULL, 1) != 0)
-		printk(KERN_ERR "Timed out waiting for drm cache flush\n");
 #endif
 }
 EXPORT_SYMBOL(drm_clflush_pages);