drm/i915/gvt: Missed to cancel dma map for ggtt entries

We have canceled dma map for ppgtt entries. Also we need to do it for
ggtt entries when them are invalidated.

This can fix task hung issue as:
[13517.791767] INFO: task gvt_service_thr:1081 blocked for more than 120 seconds.
[13517.792584] Not tainted 4.14.15+ #3
[13517.793417] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[13517.794267] gvt_service_thr D 0 1081 2 0x80000000
[13517.795132] Call Trace:
[13517.795996] ? __schedule+0x493/0x77b
[13517.796859] schedule+0x79/0x82
[13517.797740] schedule_preempt_disabled+0x5/0x6
[13517.798614] __mutex_lock.isra.0+0x2b5/0x445
[13517.799504] ? __switch_to_asm+0x24/0x60
[13517.800381] ? intel_gvt_cleanup+0x10/0x10
[13517.801261] ? intel_gvt_schedule+0x19/0x2b9
[13517.802107] intel_gvt_schedule+0x19/0x2b9
[13517.802954] ? intel_gvt_cleanup+0x10/0x10
[13517.803824] gvt_service_thread+0xe3/0x10d
[13517.804704] ? wait_woken+0x68/0x68
[13517.805588] kthread+0x118/0x120
[13517.806478] ? kthread_create_on_node+0x3a/0x3a
[13517.807381] ? call_usermodehelper_exec_async+0x113/0x11a
[13517.808307] ret_from_fork+0x35/0x40

v3: split out ggtt reset case.
v2: also unmap ggtt during reset.
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -530,6 +530,16 @@ static void ggtt_set_guest_entry(struct intel_vgpu_mm *mm,
 			   false, 0, mm->vgpu);
 }
 
+static void ggtt_get_host_entry(struct intel_vgpu_mm *mm,
+		struct intel_gvt_gtt_entry *entry, unsigned long index)
+{
+	struct intel_gvt_gtt_pte_ops *pte_ops = mm->vgpu->gvt->gtt.pte_ops;
+
+	GEM_BUG_ON(mm->type != INTEL_GVT_MM_GGTT);
+
+	pte_ops->get_entry(NULL, entry, index, false, 0, mm->vgpu);
+}
+
 static void ggtt_set_host_entry(struct intel_vgpu_mm *mm,
 		struct intel_gvt_gtt_entry *entry, unsigned long index)
 {
@@ -1818,6 +1828,18 @@ int intel_vgpu_emulate_ggtt_mmio_read(struct intel_vgpu *vgpu, unsigned int off,
 	return ret;
 }
 
+static void ggtt_invalidate_pte(struct intel_vgpu *vgpu,
+		struct intel_gvt_gtt_entry *entry)
+{
+	struct intel_gvt_gtt_pte_ops *pte_ops = vgpu->gvt->gtt.pte_ops;
+	unsigned long pfn;
+
+	pfn = pte_ops->get_pfn(entry);
+	if (pfn != vgpu->gvt->gtt.scratch_mfn)
+		intel_gvt_hypervisor_dma_unmap_guest_page(vgpu,
+						pfn << PAGE_SHIFT);
+}
+
 static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
 	void *p_data, unsigned int bytes)
 {
@@ -1844,10 +1866,10 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
 
 	memcpy((void *)&e.val64 + (off & (info->gtt_entry_size - 1)), p_data,
 			bytes);
-	m = e;
 
 	if (ops->test_present(&e)) {
 		gfn = ops->get_pfn(&e);
+		m = e;
 
 		/* one PTE update may be issued in multiple writes and the
 		 * first write may not construct a valid gfn
@@ -1868,8 +1890,12 @@ static int emulate_ggtt_mmio_write(struct intel_vgpu *vgpu, unsigned int off,
 			ops->set_pfn(&m, gvt->gtt.scratch_mfn);
 		} else
 			ops->set_pfn(&m, dma_addr >> PAGE_SHIFT);
-	} else
+	} else {
+		ggtt_get_host_entry(ggtt_mm, &m, g_gtt_index);
+		ggtt_invalidate_pte(vgpu, &m);
 		ops->set_pfn(&m, gvt->gtt.scratch_mfn);
+		ops->clear_present(&m);
+	}
 
 out:
 	ggtt_set_host_entry(ggtt_mm, &m, g_gtt_index);