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powerpc/powernv: Add indirect levels to it_userspace

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We want to support sparse memory and therefore huge chunks of DMA windows
do not need to be mapped. If a DMA window big enough to require 2 or more
indirect levels, and a DMA window is used to map all RAM (which is
a default case for 64bit window), we can actually save some memory by
not allocation TCE for regions which we are not going to map anyway.

The hardware tables alreary support indirect levels but we also keep
host-physical-to-userspace translation array which is allocated by
vmalloc() and is a flat array which might use quite some memory.

This converts it_userspace from vmalloc'ed array to a multi level table.

As the format becomes platform dependend, this replaces the direct access
to it_usespace with a iommu_table_ops::useraddrptr hook which returns
a pointer to the userspace copy of a TCE; future extension will return
NULL if the level was not allocated.

This should not change non-KVM handling of TCE tables and it_userspace
will not be allocated for non-KVM tables.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy
2018-07-04 16:13:47 +10:00
committed by Michael Ellerman
parent 00a5c58d94
commit 090bad39b2
6 changed files with 73 additions and 78 deletions
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3
arch/powerpc/platforms/powernv/pci.h
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@@ -267,11 +267,12 @@ extern int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
extern void pnv_tce_free(struct iommu_table *tbl, long index, long npages);
extern int pnv_tce_xchg(struct iommu_table *tbl, long index,
unsigned long *hpa, enum dma_data_direction *direction);
extern __be64 *pnv_tce_useraddrptr(struct iommu_table *tbl, long index);
extern unsigned long pnv_tce_get(struct iommu_table *tbl, long index);
extern long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset,
__u32 page_shift, __u64 window_size, __u32 levels,
struct iommu_table *tbl);
bool alloc_userspace_copy, struct iommu_table *tbl);
extern void pnv_pci_ioda2_table_free_pages(struct iommu_table *tbl);
extern long pnv_pci_link_table_and_group(int node, int num,