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Commit a5f10055 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

s390/pci: handle insufficient resources during dma tlb flush 



In a virtualized setup lazy flushing can lead to the hypervisor
running out of resources when lots of guest pages need to be
pinned. In this situation simply trigger a global flush to give
the hypervisor a chance to free some of these resources.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: default avatarPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent d39a01ef

arch/s390/pci/pci_dma.c

+19 −2
Original line number Diff line number Diff line
@@ -181,6 +181,9 @@ static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa, 
static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,

			   size_t size, int flags)

{

	unsigned long irqflags;

	int ret;



	/*

	 * With zdev->tlb_refresh == 0, rpcit is not required to establish new

	 * translations when previously invalid translation-table entries are
@@ -196,8 +199,22 @@ static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr, 
			return 0;

	}



	return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,

	ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,

				 PAGE_ALIGN(size));

	if (ret == -ENOMEM && !s390_iommu_strict) {

		/* enable the hypervisor to free some resources */

		if (zpci_refresh_global(zdev))

			goto out;



		spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);

		bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,

			      zdev->lazy_bitmap, zdev->iommu_pages);

		bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);

		spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);

		ret = 0;

	}

out:

	return ret;

}



static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,

arch/s390/pci/pci_insn.c

+3 −0
Original line number Diff line number Diff line
@@ -89,6 +89,9 @@ int zpci_refresh_trans(u64 fn, u64 addr, u64 range) 
	if (cc)

		zpci_err_insn(cc, status, addr, range);



	if (cc == 1 && (status == 4 || status == 16))

		return -ENOMEM;



	return (cc) ? -EIO : 0;

}