drm/amdgpu/gmc: use PCI BARs for APUs in passthrough

If the GPU is passed through to a guest VM, use the PCI
BAR for CPU FB access rather than the physical address of
carve out.  The physical address is not valid in a guest.

v2: Fix HDP handing as suggested by Michel
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -5733,7 +5733,7 @@ void amdgpu_device_flush_hdp(struct amdgpu_device *adev,
 		struct amdgpu_ring *ring)
 {
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU)
+	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev))
 		return;
 #endif
 	if (adev->gmc.xgmi.connected_to_cpu)
@@ -5749,7 +5749,7 @@ void amdgpu_device_invalidate_hdp(struct amdgpu_device *adev,
 		struct amdgpu_ring *ring)
 {
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU)
+	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev))
 		return;
 #endif
 	if (adev->gmc.xgmi.connected_to_cpu)

drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c

@@ -814,7 +814,7 @@ static int gmc_v10_0_mc_init(struct amdgpu_device *adev)
 	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
 
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU) {
+	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) {
 		adev->gmc.aper_base = adev->gfxhub.funcs->get_mc_fb_offset(adev);
 		adev->gmc.aper_size = adev->gmc.real_vram_size;
 	}

drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c

@@ -381,8 +381,9 @@ static int gmc_v7_0_mc_init(struct amdgpu_device *adev)
 	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
 
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU &&
-	    adev->gmc.real_vram_size > adev->gmc.aper_size) {
+	if ((adev->flags & AMD_IS_APU) &&
+	    adev->gmc.real_vram_size > adev->gmc.aper_size &&
+	    !amdgpu_passthrough(adev)) {
 		adev->gmc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
 		adev->gmc.aper_size = adev->gmc.real_vram_size;
 	}

drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c

@@ -581,7 +581,7 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
 	adev->gmc.aper_size = pci_resource_len(adev->pdev, 0);
 
 #ifdef CONFIG_X86_64
-	if (adev->flags & AMD_IS_APU) {
+	if ((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) {
 		adev->gmc.aper_base = ((u64)RREG32(mmMC_VM_FB_OFFSET)) << 22;
 		adev->gmc.aper_size = adev->gmc.real_vram_size;
 	}

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

@@ -1456,7 +1456,7 @@ static int gmc_v9_0_mc_init(struct amdgpu_device *adev)
 	 */
 
 	/* check whether both host-gpu and gpu-gpu xgmi links exist */
-	if ((adev->flags & AMD_IS_APU) ||
+	if (((adev->flags & AMD_IS_APU) && !amdgpu_passthrough(adev)) ||
 	    (adev->gmc.xgmi.supported &&
 	     adev->gmc.xgmi.connected_to_cpu)) {
 		adev->gmc.aper_base =