iommu/vt-d: Clear Page Request Overflow fault bit

Currently Page Request Overflow bit in IOMMU Fault Status register
is not cleared. Not clearing this bit would mean that any  future
page-request is going to be automatically dropped by IOMMU.
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/iommu/dmar.c

@@ -1679,7 +1679,8 @@ irqreturn_t dmar_fault(int irq, void *dev_id)
 		raw_spin_lock_irqsave(&iommu->register_lock, flag);
 	}
 
-	writel(DMA_FSTS_PFO | DMA_FSTS_PPF, iommu->reg + DMAR_FSTS_REG);
+	writel(DMA_FSTS_PFO | DMA_FSTS_PPF | DMA_FSTS_PRO,
+	       iommu->reg + DMAR_FSTS_REG);
 
 unlock_exit:
 	raw_spin_unlock_irqrestore(&iommu->register_lock, flag);

include/linux/intel-iommu.h

@@ -212,6 +212,7 @@
 #define DMA_FSTS_IQE (1 << 4)
 #define DMA_FSTS_ICE (1 << 5)
 #define DMA_FSTS_ITE (1 << 6)
+#define DMA_FSTS_PRO (1 << 7)
 #define dma_fsts_fault_record_index(s) (((s) >> 8) & 0xff)
 
 /* FRCD_REG, 32 bits access */