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Commit 9baf0920 authored by Bing Niu's avatar Bing Niu Committed by Zhenyu Wang
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drm/i915/gvt: don't rely on guest PPGTT entry to free old shadow data 



On guest writing a PPGTT entry, if it contains value and the old
entry is valid, gvt will read it and find & free the corresponding
old data for it. However, with the KVM write protection provided
by page_track, the guest entry will be written with new value
before gvt handling. To avoid that, we should use the shadow
entry instead.

Signed-off-by: default avatarBing Niu <bing.niu@intel.com>
Signed-off-by: default avatarJike Song <jike.song@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
parent 11840e2f

drivers/gpu/drm/i915/gvt/gtt.c

+17 −34
Original line number Diff line number Diff line
@@ -974,7 +974,7 @@ static int ppgtt_populate_shadow_page(struct intel_vgpu_ppgtt_spt *spt) 
}



static int ppgtt_handle_guest_entry_removal(struct intel_vgpu_guest_page *gpt,

		struct intel_gvt_gtt_entry *we, unsigned long index)

		unsigned long index)

{

	struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);

	struct intel_vgpu_shadow_page *sp = &spt->shadow_page;
@@ -983,25 +983,26 @@ static int ppgtt_handle_guest_entry_removal(struct intel_vgpu_guest_page *gpt, 
	struct intel_gvt_gtt_entry e;

	int ret;



	trace_gpt_change(spt->vgpu->id, "remove", spt, sp->type,

		we->val64, index);



	ppgtt_get_shadow_entry(spt, &e, index);



	trace_gpt_change(spt->vgpu->id, "remove", spt, sp->type, e.val64,

			 index);



	if (!ops->test_present(&e))

		return 0;



	if (ops->get_pfn(&e) == vgpu->gtt.scratch_pt[sp->type].page_mfn)

		return 0;



	if (gtt_type_is_pt(get_next_pt_type(we->type))) {

		struct intel_vgpu_guest_page *g =

			intel_vgpu_find_guest_page(vgpu, ops->get_pfn(we));

		if (!g) {

	if (gtt_type_is_pt(get_next_pt_type(e.type))) {

		struct intel_vgpu_ppgtt_spt *s =

			ppgtt_find_shadow_page(vgpu, ops->get_pfn(&e));

		if (!s) {

			gvt_err("fail to find guest page\n");

			ret = -ENXIO;

			goto fail;

		}

		ret = ppgtt_invalidate_shadow_page(guest_page_to_ppgtt_spt(g));

		ret = ppgtt_invalidate_shadow_page(s);

		if (ret)

			goto fail;

	}
@@ -1010,7 +1011,7 @@ static int ppgtt_handle_guest_entry_removal(struct intel_vgpu_guest_page *gpt, 
	return 0;

fail:

	gvt_err("vgpu%d: fail: shadow page %p guest entry 0x%llx type %d\n",

			vgpu->id, spt, we->val64, we->type);

			vgpu->id, spt, e.val64, e.type);

	return ret;

}
@@ -1231,23 +1232,16 @@ static int ppgtt_handle_guest_write_page_table( 
	struct intel_vgpu_ppgtt_spt *spt = guest_page_to_ppgtt_spt(gpt);

	struct intel_vgpu *vgpu = spt->vgpu;

	struct intel_gvt_gtt_pte_ops *ops = vgpu->gvt->gtt.pte_ops;

	struct intel_gvt_gtt_entry ge;



	int old_present, new_present;

	int ret;

	int new_present;



	ppgtt_get_guest_entry(spt, &ge, index);



	old_present = ops->test_present(&ge);

	new_present = ops->test_present(we);



	ppgtt_set_guest_entry(spt, we, index);



	if (old_present) {

		ret = ppgtt_handle_guest_entry_removal(gpt, &ge, index);

	ret = ppgtt_handle_guest_entry_removal(gpt, index);

	if (ret)

		goto fail;

	}



	if (new_present) {

		ret = ppgtt_handle_guest_entry_add(gpt, we, index);

		if (ret)
@@ -1293,7 +1287,7 @@ int intel_vgpu_flush_post_shadow(struct intel_vgpu *vgpu) 
{

	struct list_head *pos, *n;

	struct intel_vgpu_ppgtt_spt *spt;

	struct intel_gvt_gtt_entry ge, e;

	struct intel_gvt_gtt_entry ge;

	unsigned long index;

	int ret;
@@ -1304,9 +1298,6 @@ int intel_vgpu_flush_post_shadow(struct intel_vgpu *vgpu) 
		for_each_set_bit(index, spt->post_shadow_bitmap,

				GTT_ENTRY_NUM_IN_ONE_PAGE) {

			ppgtt_get_guest_entry(spt, &ge, index);

			e = ge;

			e.val64 = 0;

			ppgtt_set_guest_entry(spt, &e, index);



			ret = ppgtt_handle_guest_write_page_table(

					&spt->guest_page, &ge, index);
@@ -1334,8 +1325,6 @@ static int ppgtt_handle_guest_write_page_table_bytes(void *gp, 
	index = (pa & (PAGE_SIZE - 1)) >> info->gtt_entry_size_shift;



	ppgtt_get_guest_entry(spt, &we, index);

	memcpy((void *)&we.val64 + (pa & (info->gtt_entry_size - 1)),

			p_data, bytes);



	ops->test_pse(&we);
@@ -1344,19 +1333,13 @@ static int ppgtt_handle_guest_write_page_table_bytes(void *gp, 
		if (ret)

			return ret;

	} else {

		struct intel_gvt_gtt_entry ge;



		ppgtt_get_guest_entry(spt, &ge, index);



		if (!test_bit(index, spt->post_shadow_bitmap)) {

			ret = ppgtt_handle_guest_entry_removal(gpt,

					&ge, index);

			ret = ppgtt_handle_guest_entry_removal(gpt, index);

			if (ret)

				return ret;

		}



		ppgtt_set_post_shadow(spt, index);

		ppgtt_set_guest_entry(spt, &we, index);

	}



	if (!enable_out_of_sync)