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powerpc/powernv/iommu: Add real mode version of iommu_table_ops::exchange()

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In real mode, TCE tables are invalidated using special
cache-inhibited store instructions which are not available in
virtual mode

This defines and implements exchange_rm() callback. This does not
define set_rm/clear_rm/flush_rm callbacks as there is no user for those -
exchange/exchange_rm are only to be used by KVM for VFIO.

The exchange_rm callback is defined for IODA1/IODA2 powernv platforms.

This replaces list_for_each_entry_rcu with its lockless version as
from now on pnv_pci_ioda2_tce_invalidate() can be called in
the real mode too.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy
2017-03-22 15:21:48 +11:00
committed by Michael Ellerman
parent 6b5c19c552
commit a540aa56ba
3 changed files with 57 additions and 1 deletions
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25
arch/powerpc/kernel/iommu.c
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@@ -1004,6 +1004,31 @@ long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
}
EXPORT_SYMBOL_GPL(iommu_tce_xchg);
#ifdef CONFIG_PPC_BOOK3S_64
long iommu_tce_xchg_rm(struct iommu_table *tbl, unsigned long entry,
unsigned long *hpa, enum dma_data_direction *direction)
{
long ret;
ret = tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
if (!ret && ((*direction == DMA_FROM_DEVICE) ||
(*direction == DMA_BIDIRECTIONAL))) {
struct page *pg = realmode_pfn_to_page(*hpa >> PAGE_SHIFT);
if (likely(pg)) {
SetPageDirty(pg);
} else {
tbl->it_ops->exchange_rm(tbl, entry, hpa, direction);
ret = -EFAULT;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(iommu_tce_xchg_rm);
#endif
int iommu_take_ownership(struct iommu_table *tbl)
{
unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;