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drm/i915/gvt: support inconsecutive partial gtt entry write

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Previously we assumed two 4-byte writes to the same PTE coming in sequence.
But recently we observed inconsecutive partial write happening as well. So
this patch enhances the previous solution. It now uses a list to save more
partial writes. If one partial write can be combined with another one in
the list to construct a full PTE, update its shadow entry. Otherwise, save
the partial write in the list.

v2: invalidate old entry and flush ggtt (Zhenyu)
v3: split old ggtt page unmap to another patch (Zhenyu)
v4: refine codes (Zhenyu)

Signed-off-by: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Yan Zhao <yan.y.zhao@intel.com>
Cc: Xiaolin Zhang <xiaolin.zhang@intel.com>
Cc: Zhenyu Wang <zhenyu.z.wang@intel.com>
Reviewed-by: Xiaolin Zhang <xiaolin.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
This commit is contained in:
Hang Yuan 2018-09-19 14:42:10 +08:00 • committed by Zhenyu Wang
parent f42259ef81
commit bc0686ff5f
2 changed files with 56 additions and 52 deletions
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95
drivers/gpu/drm/i915/gvt/gtt.c
View file

@ -1901,7 +1901,6 @@ static struct intel_vgpu_mm *intel_vgpu_create_ggtt_mm(struct intel_vgpu *vgpu)
vgpu_free_mm(mm);
return ERR_PTR(-ENOMEM);
}
mm->ggtt_mm.last_partial_off = -1UL;
return mm;
}
@ -1926,7 +1925,6 @@ void _intel_vgpu_mm_release(struct kref *mm_ref)
invalidate_ppgtt_mm(mm);
} else {
vfree(mm->ggtt_mm.virtual_ggtt);
mm->ggtt_mm.last_partial_off = -1UL;
}
vgpu_free_mm(mm);
@ -2164,6 +2162,8 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
struct intel_gvt_gtt_entry e, m;
dma_addr_t dma_addr;
int ret;
struct intel_gvt_partial_pte *partial_pte, *pos, *n;
bool partial_update = false;
if (bytes != 4 && bytes != 8)
return -EINVAL;
@ -2174,68 +2174,57 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
if (!vgpu_gmadr_is_valid(vgpu, gma))
return 0;
ggtt_get_guest_entry(ggtt_mm, &e, g_gtt_index);
e.type = GTT_TYPE_GGTT_PTE;
memcpy((void *)&e.val64 + (off & (info->gtt_entry_size - 1)), p_data,
bytes);
/* If ggtt entry size is 8 bytes, and it's split into two 4 bytes
* write, we assume the two 4 bytes writes are consecutive.
* Otherwise, we abort and report error
* write, save the first 4 bytes in a list and update virtual
* PTE. Only update shadow PTE when the second 4 bytes comes.
*/
if (bytes < info->gtt_entry_size) {
if (ggtt_mm->ggtt_mm.last_partial_off == -1UL) {
/* the first partial part*/
ggtt_mm->ggtt_mm.last_partial_off = off;
ggtt_mm->ggtt_mm.last_partial_data = e.val64;
return 0;
} else if ((g_gtt_index ==
(ggtt_mm->ggtt_mm.last_partial_off >>
info->gtt_entry_size_shift)) &&
(off != ggtt_mm->ggtt_mm.last_partial_off)) {
/* the second partial part */
bool found = false;
int last_off = ggtt_mm->ggtt_mm.last_partial_off &
list_for_each_entry_safe(pos, n,
&ggtt_mm->ggtt_mm.partial_pte_list, list) {
if (g_gtt_index == pos->offset >>
info->gtt_entry_size_shift) {
if (off != pos->offset) {
/* the second partial part*/
int last_off = pos->offset &
(info->gtt_entry_size - 1);
memcpy((void *)&e.val64 + last_off,
(void *)&ggtt_mm->ggtt_mm.last_partial_data +
last_off, bytes);
(void *)&pos->data + last_off,
bytes);
ggtt_mm->ggtt_mm.last_partial_off = -1UL;
} else {
int last_offset;
gvt_vgpu_err("failed to populate guest ggtt entry: abnormal ggtt entry write sequence, last_partial_off=%lx, offset=%x, bytes=%d, ggtt entry size=%d\n",
ggtt_mm->ggtt_mm.last_partial_off, off,
bytes, info->gtt_entry_size);
/* set host ggtt entry to scratch page and clear
* virtual ggtt entry as not present for last
* partially write offset
*/
last_offset = ggtt_mm->ggtt_mm.last_partial_off &
(~(info->gtt_entry_size - 1));
ggtt_get_host_entry(ggtt_mm, &m, last_offset);
ggtt_invalidate_pte(vgpu, &m);
ops->set_pfn(&m, gvt->gtt.scratch_mfn);
ops->clear_present(&m);
ggtt_set_host_entry(ggtt_mm, &m, last_offset);
ggtt_invalidate(gvt->dev_priv);
ggtt_get_guest_entry(ggtt_mm, &e, last_offset);
ops->clear_present(&e);
ggtt_set_guest_entry(ggtt_mm, &e, last_offset);
ggtt_mm->ggtt_mm.last_partial_off = off;
ggtt_mm->ggtt_mm.last_partial_data = e.val64;
list_del(&pos->list);
kfree(pos);
found = true;
break;
}
/* update of the first partial part */
pos->data = e.val64;
ggtt_set_guest_entry(ggtt_mm, &e, g_gtt_index);
return 0;
}
}
if (ops->test_present(&e)) {
if (!found) {
/* the first partial part */
partial_pte = kzalloc(sizeof(*partial_pte), GFP_KERNEL);
if (!partial_pte)
return -ENOMEM;
partial_pte->offset = off;
partial_pte->data = e.val64;
list_add_tail(&partial_pte->list,
&ggtt_mm->ggtt_mm.partial_pte_list);
partial_update = true;
}
}
if (!partial_update && (ops->test_present(&e))) {
gfn = ops->get_pfn(&e);
m = e;
@ -2428,6 +2417,8 @@ int intel_vgpu_init_gtt(struct intel_vgpu *vgpu)
intel_vgpu_reset_ggtt(vgpu, false);
INIT_LIST_HEAD(&gtt->ggtt_mm->ggtt_mm.partial_pte_list);
return create_scratch_page_tree(vgpu);
}
@ -2452,6 +2443,14 @@ static void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu)
static void intel_vgpu_destroy_ggtt_mm(struct intel_vgpu *vgpu)
{
struct intel_gvt_partial_pte *pos;
list_for_each_entry(pos,
&vgpu->gtt.ggtt_mm->ggtt_mm.partial_pte_list, list) {
gvt_dbg_mm("partial PTE update on hold 0x%lx : 0x%llx\n",
pos->offset, pos->data);
kfree(pos);
}
intel_vgpu_destroy_mm(vgpu->gtt.ggtt_mm);
vgpu->gtt.ggtt_mm = NULL;
}

9
drivers/gpu/drm/i915/gvt/gtt.h
View file

@ -133,6 +133,12 @@ enum intel_gvt_mm_type {
#define GVT_RING_CTX_NR_PDPS GEN8_3LVL_PDPES
struct intel_gvt_partial_pte {
unsigned long offset;
u64 data;
struct list_head list;
};
struct intel_vgpu_mm {
enum intel_gvt_mm_type type;
struct intel_vgpu *vgpu;
@ -157,8 +163,7 @@ struct intel_vgpu_mm {
} ppgtt_mm;
struct {
void *virtual_ggtt;
unsigned long last_partial_off;
u64 last_partial_data;
struct list_head partial_pte_list;
} ggtt_mm;
};
};