drm/i915/gvt: vGPU graphics memory virtualization

The vGPU graphics memory emulation framework is responsible for graphics
memory table virtualization. Under virtualization environment, a VM will
populate the page table entry with guest page frame number(GPFN/GFN), while
HW needs a page table filled with MFN(Machine frame number). The
relationship between GFN and MFN(Machine frame number) is managed by
hypervisor, while GEN HW doesn't have such knowledge to translate a GFN.

To solve this gap, shadow GGTT/PPGTT page table is introdcued.

For GGTT, the GFN inside the guest GGTT page table entry will be translated
into MFN and written into physical GTT MMIO registers when guest write
virtual GTT MMIO registers.

For PPGTT, a shadow PPGTT page table will be created and write-protected
translated from guest PPGTT page table.  And the shadow page table root
pointers will be written into the shadow context after a guest workload
is shadowed.

vGPU graphics memory emulation framework consists:

- Per-GEN HW platform page table entry bits extract/de-extract routines.
- GTT MMIO register emulation handlers, which will call hypercall to do
GFN->MFN translation when guest write GTT MMIO register
- PPGTT shadow page table routines, e.g. shadow create/destroy/out-of-sync

Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 107 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/mpt.h b/drivers/gpu/drm/i915/gvt/mpt.h
index 31a837195745..46664771cc58 100644
--- a/drivers/gpu/drm/i915/gvt/mpt.h
+++ b/drivers/gpu/drm/i915/gvt/mpt.h
@@ -117,4 +117,111 @@ static inline int intel_gvt_hypervisor_inject_msi(struct intel_vgpu *vgpu)
 	return 0;
 }
 
+/**
+ * intel_gvt_hypervisor_set_wp_page - translate a host VA into MFN
+ * @p: host kernel virtual address
+ *
+ * Returns:
+ * MFN on success, INTEL_GVT_INVALID_ADDR if failed.
+ */
+static inline unsigned long intel_gvt_hypervisor_virt_to_mfn(void *p)
+{
+	return intel_gvt_host.mpt->from_virt_to_mfn(p);
+}
+
+/**
+ * intel_gvt_hypervisor_set_wp_page - set a guest page to write-protected
+ * @vgpu: a vGPU
+ * @p: intel_vgpu_guest_page
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline int intel_gvt_hypervisor_set_wp_page(struct intel_vgpu *vgpu,
+		struct intel_vgpu_guest_page *p)
+{
+	int ret;
+
+	if (p->writeprotection)
+		return 0;
+
+	ret = intel_gvt_host.mpt->set_wp_page(vgpu->handle, p->gfn);
+	if (ret)
+		return ret;
+	p->writeprotection = true;
+	atomic_inc(&vgpu->gtt.n_write_protected_guest_page);
+	return 0;
+}
+
+/**
+ * intel_gvt_hypervisor_unset_wp_page - remove the write-protection of a
+ * guest page
+ * @vgpu: a vGPU
+ * @p: intel_vgpu_guest_page
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline int intel_gvt_hypervisor_unset_wp_page(struct intel_vgpu *vgpu,
+		struct intel_vgpu_guest_page *p)
+{
+	int ret;
+
+	if (!p->writeprotection)
+		return 0;
+
+	ret = intel_gvt_host.mpt->unset_wp_page(vgpu->handle, p->gfn);
+	if (ret)
+		return ret;
+	p->writeprotection = false;
+	atomic_dec(&vgpu->gtt.n_write_protected_guest_page);
+	return 0;
+}
+
+/**
+ * intel_gvt_hypervisor_read_gpa - copy data from GPA to host data buffer
+ * @vgpu: a vGPU
+ * @gpa: guest physical address
+ * @buf: host data buffer
+ * @len: data length
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline int intel_gvt_hypervisor_read_gpa(struct intel_vgpu *vgpu,
+		unsigned long gpa, void *buf, unsigned long len)
+{
+	return intel_gvt_host.mpt->read_gpa(vgpu->handle, gpa, buf, len);
+}
+
+/**
+ * intel_gvt_hypervisor_write_gpa - copy data from host data buffer to GPA
+ * @vgpu: a vGPU
+ * @gpa: guest physical address
+ * @buf: host data buffer
+ * @len: data length
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+static inline int intel_gvt_hypervisor_write_gpa(struct intel_vgpu *vgpu,
+		unsigned long gpa, void *buf, unsigned long len)
+{
+	return intel_gvt_host.mpt->write_gpa(vgpu->handle, gpa, buf, len);
+}
+
+/**
+ * intel_gvt_hypervisor_gfn_to_mfn - translate a GFN to MFN
+ * @vgpu: a vGPU
+ * @gpfn: guest pfn
+ *
+ * Returns:
+ * MFN on success, INTEL_GVT_INVALID_ADDR if failed.
+ */
+static inline unsigned long intel_gvt_hypervisor_gfn_to_mfn(
+		struct intel_vgpu *vgpu, unsigned long gfn)
+{
+	return intel_gvt_host.mpt->gfn_to_mfn(vgpu->handle, gfn);
+}
+
 #endif /* _GVT_MPT_H_ */