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: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index f7aa5a7..2d15d84 100644 (file)
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -181,6 +181,9 @@ out_unlock:
 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,
-                                 PAGE_ALIGN(size));
+       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,

diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
index 19bcb3b..f069929 100644 (file)
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -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;
 }