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mm: simplify device private page handling in hmm_range_fault

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Remove the HMM_PFN_DEVICE_PRIVATE flag, no driver has ever set this flag
on input, and the only place that uses it on output can be trivially
changed to use is_device_private_page().

This removes the ability to request that device_private pages are faulted
back into system memory.

Link: https://lore.kernel.org/r/20200316193216.920734-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Christoph Hellwig 2020-03-16 20:32:15 +01:00 committed by Jason Gunthorpe
parent 800bb1c8dc
commit 17ffdc4829
5 changed files with 8 additions and 26 deletions
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1
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
View File

@ -776,7 +776,6 @@ struct amdgpu_ttm_tt {
static const uint64_t hmm_range_flags[HMM_PFN_FLAG_MAX] = {
(1 << 0), /* HMM_PFN_VALID */
(1 << 1), /* HMM_PFN_WRITE */
0 /* HMM_PFN_DEVICE_PRIVATE */
};
static const uint64_t hmm_range_values[HMM_PFN_VALUE_MAX] = {

5
drivers/gpu/drm/nouveau/nouveau_dmem.c
View File

@ -28,6 +28,7 @@
#include <nvif/class.h>
#include <nvif/object.h>
#include <nvif/if000c.h>
#include <nvif/if500b.h>
#include <nvif/if900b.h>
@ -692,9 +693,8 @@ nouveau_dmem_convert_pfn(struct nouveau_drm *drm,
if (page == NULL)
continue;
if (!(range->pfns[i] & range->flags[HMM_PFN_DEVICE_PRIVATE])) {
if (!is_device_private_page(page))
continue;
}
if (!nouveau_dmem_page(drm, page)) {
WARN(1, "Some unknown device memory !\n");
@ -705,5 +705,6 @@ nouveau_dmem_convert_pfn(struct nouveau_drm *drm,
addr = nouveau_dmem_page_addr(page);
range->pfns[i] &= ((1UL << range->pfn_shift) - 1);
range->pfns[i] |= (addr >> PAGE_SHIFT) << range->pfn_shift;
range->pfns[i] |= NVIF_VMM_PFNMAP_V0_VRAM;
}
}

1
drivers/gpu/drm/nouveau/nouveau_svm.c
View File

@ -367,7 +367,6 @@ static const u64
nouveau_svm_pfn_flags[HMM_PFN_FLAG_MAX] = {
[HMM_PFN_VALID ] = NVIF_VMM_PFNMAP_V0_V,
[HMM_PFN_WRITE ] = NVIF_VMM_PFNMAP_V0_W,
[HMM_PFN_DEVICE_PRIVATE] = NVIF_VMM_PFNMAP_V0_VRAM,
};
static const u64

2
include/linux/hmm.h
View File

@ -74,7 +74,6 @@
* Flags:
* HMM_PFN_VALID: pfn is valid. It has, at least, read permission.
* HMM_PFN_WRITE: CPU page table has write permission set
* HMM_PFN_DEVICE_PRIVATE: private device memory (ZONE_DEVICE)
*
* The driver provides a flags array for mapping page protections to device
* PTE bits. If the driver valid bit for an entry is bit 3,
@ -86,7 +85,6 @@
enum hmm_pfn_flag_e {
HMM_PFN_VALID = 0,
HMM_PFN_WRITE,
HMM_PFN_DEVICE_PRIVATE,
HMM_PFN_FLAG_MAX
};

25
mm/hmm.c
View File

@ -116,15 +116,6 @@ static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
/* We aren't ask to do anything ... */
if (!(pfns & range->flags[HMM_PFN_VALID]))
return;
/* If this is device memory then only fault if explicitly requested */
if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) {
/* Do we fault on device memory ? */
if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) {
*write_fault = pfns & range->flags[HMM_PFN_WRITE];
*fault = true;
}
return;
}
/* If CPU page table is not valid then we need to fault */
*fault = !(cpu_flags & range->flags[HMM_PFN_VALID]);
@ -262,21 +253,15 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
swp_entry_t entry = pte_to_swp_entry(pte);
/*
* This is a special swap entry, ignore migration, use
* device and report anything else as error.
* Never fault in device private pages pages, but just report
* the PFN even if not present.
*/
if (is_device_private_entry(entry)) {
cpu_flags = range->flags[HMM_PFN_VALID] |
range->flags[HMM_PFN_DEVICE_PRIVATE];
cpu_flags |= is_write_device_private_entry(entry) ?
range->flags[HMM_PFN_WRITE] : 0;
hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags,
&fault, &write_fault);
if (fault || write_fault)
goto fault;
*pfn = hmm_device_entry_from_pfn(range,
swp_offset(entry));
*pfn |= cpu_flags;
*pfn |= range->flags[HMM_PFN_VALID];
if (is_write_device_private_entry(entry))
*pfn |= range->flags[HMM_PFN_WRITE];
return 0;
}