blob: 74ff2812d66a1b9d08ae92db9f74bc58007b241e [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0 OR MIT
/**************************************************************************
*
* Copyright 2019-2023 VMware, Inc., Palo Alto, CA., USA
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
#include "vmwgfx_bo.h"
#include "vmwgfx_drv.h"
/*
* Different methods for tracking dirty:
* VMW_BO_DIRTY_PAGETABLE - Scan the pagetable for hardware dirty bits
* VMW_BO_DIRTY_MKWRITE - Write-protect page table entries and record write-
* accesses in the VM mkwrite() callback
*/
enum vmw_bo_dirty_method {
VMW_BO_DIRTY_PAGETABLE,
VMW_BO_DIRTY_MKWRITE,
};
/*
* No dirtied pages at scan trigger a transition to the _MKWRITE method,
* similarly a certain percentage of dirty pages trigger a transition to
* the _PAGETABLE method. How many triggers should we wait for before
* changing method?
*/
#define VMW_DIRTY_NUM_CHANGE_TRIGGERS 2
/* Percentage to trigger a transition to the _PAGETABLE method */
#define VMW_DIRTY_PERCENTAGE 10
/**
* struct vmw_bo_dirty - Dirty information for buffer objects
* @start: First currently dirty bit
* @end: Last currently dirty bit + 1
* @method: The currently used dirty method
* @change_count: Number of consecutive method change triggers
* @ref_count: Reference count for this structure
* @bitmap_size: The size of the bitmap in bits. Typically equal to the
* nuber of pages in the bo.
* @bitmap: A bitmap where each bit represents a page. A set bit means a
* dirty page.
*/
struct vmw_bo_dirty {
unsigned long start;
unsigned long end;
enum vmw_bo_dirty_method method;
unsigned int change_count;
unsigned int ref_count;
unsigned long bitmap_size;
unsigned long bitmap[];
};
/**
* vmw_bo_dirty_scan_pagetable - Perform a pagetable scan for dirty bits
* @vbo: The buffer object to scan
*
* Scans the pagetable for dirty bits. Clear those bits and modify the
* dirty structure with the results. This function may change the
* dirty-tracking method.
*/
static void vmw_bo_dirty_scan_pagetable(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
pgoff_t offset = drm_vma_node_start(&vbo->tbo.base.vma_node);
struct address_space *mapping = vbo->tbo.bdev->dev_mapping;
pgoff_t num_marked;
num_marked = clean_record_shared_mapping_range
(mapping,
offset, dirty->bitmap_size,
offset, &dirty->bitmap[0],
&dirty->start, &dirty->end);
if (num_marked == 0)
dirty->change_count++;
else
dirty->change_count = 0;
if (dirty->change_count > VMW_DIRTY_NUM_CHANGE_TRIGGERS) {
dirty->change_count = 0;
dirty->method = VMW_BO_DIRTY_MKWRITE;
wp_shared_mapping_range(mapping,
offset, dirty->bitmap_size);
clean_record_shared_mapping_range(mapping,
offset, dirty->bitmap_size,
offset, &dirty->bitmap[0],
&dirty->start, &dirty->end);
}
}
/**
* vmw_bo_dirty_scan_mkwrite - Reset the mkwrite dirty-tracking method
* @vbo: The buffer object to scan
*
* Write-protect pages written to so that consecutive write accesses will
* trigger a call to mkwrite.
*
* This function may change the dirty-tracking method.
*/
static void vmw_bo_dirty_scan_mkwrite(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
unsigned long offset = drm_vma_node_start(&vbo->tbo.base.vma_node);
struct address_space *mapping = vbo->tbo.bdev->dev_mapping;
pgoff_t num_marked;
if (dirty->end <= dirty->start)
return;
num_marked = wp_shared_mapping_range(vbo->tbo.bdev->dev_mapping,
dirty->start + offset,
dirty->end - dirty->start);
if (100UL * num_marked / dirty->bitmap_size >
VMW_DIRTY_PERCENTAGE)
dirty->change_count++;
else
dirty->change_count = 0;
if (dirty->change_count > VMW_DIRTY_NUM_CHANGE_TRIGGERS) {
pgoff_t start = 0;
pgoff_t end = dirty->bitmap_size;
dirty->method = VMW_BO_DIRTY_PAGETABLE;
clean_record_shared_mapping_range(mapping, offset, end, offset,
&dirty->bitmap[0],
&start, &end);
bitmap_clear(&dirty->bitmap[0], 0, dirty->bitmap_size);
if (dirty->start < dirty->end)
bitmap_set(&dirty->bitmap[0], dirty->start,
dirty->end - dirty->start);
dirty->change_count = 0;
}
}
/**
* vmw_bo_dirty_scan - Scan for dirty pages and add them to the dirty
* tracking structure
* @vbo: The buffer object to scan
*
* This function may change the dirty tracking method.
*/
void vmw_bo_dirty_scan(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
if (dirty->method == VMW_BO_DIRTY_PAGETABLE)
vmw_bo_dirty_scan_pagetable(vbo);
else
vmw_bo_dirty_scan_mkwrite(vbo);
}
/**
* vmw_bo_dirty_pre_unmap - write-protect and pick up dirty pages before
* an unmap_mapping_range operation.
* @vbo: The buffer object,
* @start: First page of the range within the buffer object.
* @end: Last page of the range within the buffer object + 1.
*
* If we're using the _PAGETABLE scan method, we may leak dirty pages
* when calling unmap_mapping_range(). This function makes sure we pick
* up all dirty pages.
*/
static void vmw_bo_dirty_pre_unmap(struct vmw_bo *vbo,
pgoff_t start, pgoff_t end)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
unsigned long offset = drm_vma_node_start(&vbo->tbo.base.vma_node);
struct address_space *mapping = vbo->tbo.bdev->dev_mapping;
if (dirty->method != VMW_BO_DIRTY_PAGETABLE || start >= end)
return;
wp_shared_mapping_range(mapping, start + offset, end - start);
clean_record_shared_mapping_range(mapping, start + offset,
end - start, offset,
&dirty->bitmap[0], &dirty->start,
&dirty->end);
}
/**
* vmw_bo_dirty_unmap - Clear all ptes pointing to a range within a bo
* @vbo: The buffer object,
* @start: First page of the range within the buffer object.
* @end: Last page of the range within the buffer object + 1.
*
* This is similar to ttm_bo_unmap_virtual() except it takes a subrange.
*/
void vmw_bo_dirty_unmap(struct vmw_bo *vbo,
pgoff_t start, pgoff_t end)
{
unsigned long offset = drm_vma_node_start(&vbo->tbo.base.vma_node);
struct address_space *mapping = vbo->tbo.bdev->dev_mapping;
vmw_bo_dirty_pre_unmap(vbo, start, end);
unmap_shared_mapping_range(mapping, (offset + start) << PAGE_SHIFT,
(loff_t) (end - start) << PAGE_SHIFT);
}
/**
* vmw_bo_dirty_add - Add a dirty-tracking user to a buffer object
* @vbo: The buffer object
*
* This function registers a dirty-tracking user to a buffer object.
* A user can be for example a resource or a vma in a special user-space
* mapping.
*
* Return: Zero on success, -ENOMEM on memory allocation failure.
*/
int vmw_bo_dirty_add(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
pgoff_t num_pages = PFN_UP(vbo->tbo.resource->size);
size_t size;
int ret;
if (dirty) {
dirty->ref_count++;
return 0;
}
size = sizeof(*dirty) + BITS_TO_LONGS(num_pages) * sizeof(long);
dirty = kvzalloc(size, GFP_KERNEL);
if (!dirty) {
ret = -ENOMEM;
goto out_no_dirty;
}
dirty->bitmap_size = num_pages;
dirty->start = dirty->bitmap_size;
dirty->end = 0;
dirty->ref_count = 1;
if (num_pages < PAGE_SIZE / sizeof(pte_t)) {
dirty->method = VMW_BO_DIRTY_PAGETABLE;
} else {
struct address_space *mapping = vbo->tbo.bdev->dev_mapping;
pgoff_t offset = drm_vma_node_start(&vbo->tbo.base.vma_node);
dirty->method = VMW_BO_DIRTY_MKWRITE;
/* Write-protect and then pick up already dirty bits */
wp_shared_mapping_range(mapping, offset, num_pages);
clean_record_shared_mapping_range(mapping, offset, num_pages,
offset,
&dirty->bitmap[0],
&dirty->start, &dirty->end);
}
vbo->dirty = dirty;
return 0;
out_no_dirty:
return ret;
}
/**
* vmw_bo_dirty_release - Release a dirty-tracking user from a buffer object
* @vbo: The buffer object
*
* This function releases a dirty-tracking user from a buffer object.
* If the reference count reaches zero, then the dirty-tracking object is
* freed and the pointer to it cleared.
*
* Return: Zero on success, -ENOMEM on memory allocation failure.
*/
void vmw_bo_dirty_release(struct vmw_bo *vbo)
{
struct vmw_bo_dirty *dirty = vbo->dirty;
if (dirty && --dirty->ref_count == 0) {
kvfree(dirty);
vbo->dirty = NULL;
}
}
/**
* vmw_bo_dirty_transfer_to_res - Pick up a resource's dirty region from
* its backing mob.
* @res: The resource
*
* This function will pick up all dirty ranges affecting the resource from
* it's backup mob, and call vmw_resource_dirty_update() once for each
* range. The transferred ranges will be cleared from the backing mob's
* dirty tracking.
*/
void vmw_bo_dirty_transfer_to_res(struct vmw_resource *res)
{
struct vmw_bo *vbo = res->guest_memory_bo;
struct vmw_bo_dirty *dirty = vbo->dirty;
pgoff_t start, cur, end;
unsigned long res_start = res->guest_memory_offset;
unsigned long res_end = res->guest_memory_offset + res->guest_memory_size;
WARN_ON_ONCE(res_start & ~PAGE_MASK);
res_start >>= PAGE_SHIFT;
res_end = DIV_ROUND_UP(res_end, PAGE_SIZE);
if (res_start >= dirty->end || res_end <= dirty->start)
return;
cur = max(res_start, dirty->start);
res_end = max(res_end, dirty->end);
while (cur < res_end) {
unsigned long num;
start = find_next_bit(&dirty->bitmap[0], res_end, cur);
if (start >= res_end)
break;
end = find_next_zero_bit(&dirty->bitmap[0], res_end, start + 1);
cur = end + 1;
num = end - start;
bitmap_clear(&dirty->bitmap[0], start, num);
vmw_resource_dirty_update(res, start, end);
}
if (res_start <= dirty->start && res_end > dirty->start)
dirty->start = res_end;
if (res_start < dirty->end && res_end >= dirty->end)
dirty->end = res_start;
}
/**
* vmw_bo_dirty_clear_res - Clear a resource's dirty region from
* its backing mob.
* @res: The resource
*
* This function will clear all dirty ranges affecting the resource from
* it's backup mob's dirty tracking.
*/
void vmw_bo_dirty_clear_res(struct vmw_resource *res)
{
unsigned long res_start = res->guest_memory_offset;
unsigned long res_end = res->guest_memory_offset + res->guest_memory_size;
struct vmw_bo *vbo = res->guest_memory_bo;
struct vmw_bo_dirty *dirty = vbo->dirty;
res_start >>= PAGE_SHIFT;
res_end = DIV_ROUND_UP(res_end, PAGE_SIZE);
if (res_start >= dirty->end || res_end <= dirty->start)
return;
res_start = max(res_start, dirty->start);
res_end = min(res_end, dirty->end);
bitmap_clear(&dirty->bitmap[0], res_start, res_end - res_start);
if (res_start <= dirty->start && res_end > dirty->start)
dirty->start = res_end;
if (res_start < dirty->end && res_end >= dirty->end)
dirty->end = res_start;
}
vm_fault_t vmw_bo_vm_mkwrite(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
vma->vm_private_data;
vm_fault_t ret;
unsigned long page_offset;
unsigned int save_flags;
struct vmw_bo *vbo = to_vmw_bo(&bo->base);
/*
* mkwrite() doesn't handle the VM_FAULT_RETRY return value correctly.
* So make sure the TTM helpers are aware.
*/
save_flags = vmf->flags;
vmf->flags &= ~FAULT_FLAG_ALLOW_RETRY;
ret = ttm_bo_vm_reserve(bo, vmf);
vmf->flags = save_flags;
if (ret)
return ret;
page_offset = vmf->pgoff - drm_vma_node_start(&bo->base.vma_node);
if (unlikely(page_offset >= PFN_UP(bo->resource->size))) {
ret = VM_FAULT_SIGBUS;
goto out_unlock;
}
if (vbo->dirty && vbo->dirty->method == VMW_BO_DIRTY_MKWRITE &&
!test_bit(page_offset, &vbo->dirty->bitmap[0])) {
struct vmw_bo_dirty *dirty = vbo->dirty;
__set_bit(page_offset, &dirty->bitmap[0]);
dirty->start = min(dirty->start, page_offset);
dirty->end = max(dirty->end, page_offset + 1);
}
out_unlock:
dma_resv_unlock(bo->base.resv);
return ret;
}
vm_fault_t vmw_bo_vm_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
vma->vm_private_data;
struct vmw_bo *vbo = to_vmw_bo(&bo->base);
pgoff_t num_prefault;
pgprot_t prot;
vm_fault_t ret;
ret = ttm_bo_vm_reserve(bo, vmf);
if (ret)
return ret;
num_prefault = (vma->vm_flags & VM_RAND_READ) ? 1 :
TTM_BO_VM_NUM_PREFAULT;
if (vbo->dirty) {
pgoff_t allowed_prefault;
unsigned long page_offset;
page_offset = vmf->pgoff -
drm_vma_node_start(&bo->base.vma_node);
if (page_offset >= PFN_UP(bo->resource->size) ||
vmw_resources_clean(vbo, page_offset,
page_offset + PAGE_SIZE,
&allowed_prefault)) {
ret = VM_FAULT_SIGBUS;
goto out_unlock;
}
num_prefault = min(num_prefault, allowed_prefault);
}
/*
* If we don't track dirty using the MKWRITE method, make sure
* sure the page protection is write-enabled so we don't get
* a lot of unnecessary write faults.
*/
if (vbo->dirty && vbo->dirty->method == VMW_BO_DIRTY_MKWRITE)
prot = vm_get_page_prot(vma->vm_flags & ~VM_SHARED);
else
prot = vm_get_page_prot(vma->vm_flags);
ret = ttm_bo_vm_fault_reserved(vmf, prot, num_prefault);
if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
return ret;
out_unlock:
dma_resv_unlock(bo->base.resv);
return ret;
}