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s390/pci: handle insufficient resources during dma tlb flush

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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>
This commit is contained in:
Sebastian Ott 2017-12-01 18:47:32 +01:00 committed by Martin Schwidefsky
parent d39a01eff9
commit a5f1005517
2 changed files with 22 additions and 2 deletions
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21
arch/s390/pci/pci_dma.c
View File

@ -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,

3
arch/s390/pci/pci_insn.c
View File

@ -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;
}