[PATCH 6.19 751/844] drm/amdgpu: GPU vm support 5-level page table
From: Sasha Levin
Date: Sat Feb 28 2026 - 14:47:03 EST
From: Philip Yang <Philip.Yang@xxxxxxx>
[ Upstream commit f6b1c1f5fd7237f77fc3880603ea54dcf0371a20 ]
If GPU supports 5-level page table, but CPU disable 5-level page table
by using boot option no5lvl or CPU feature not available, the virtual
address will be 48bit, not needed to enable 5-level page table on GPU
vm.
If adev->vm_manager.num_level, number of pde levels, set to 4, then
gfxhub and mmhub register VM_CONTEXTx_CNTL/PAGE_TABLE_DEPTH will set
to 4 to enable 5-level page table in page table walker.
Set vm_manager.root_level to AMDGPU_VM_PDE3, then update GPU mapping
will allocate and update PDE3/PDE2/PDE1/PDE0/PTB 5-level page tables.
If max_level is not 4, no change for the logic to support features
needed by old ASICs.
v2: squash in CONFIG fix
Signed-off-by: Philip Yang <Philip.Yang@xxxxxxx>
Acked-by: Felix Kuehling <felix.kuehling@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Stable-dep-of: 3b948dd0366a ("drm/amdgpu: Use 5-level paging if gmc support 57-bit VA")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 20 ++++++++++++++++++++
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 3 ++-
drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 1 +
3 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index a67285118c37b..4d329454456bc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2360,9 +2360,26 @@ void amdgpu_vm_adjust_size(struct amdgpu_device *adev, uint32_t min_vm_size,
unsigned max_bits)
{
unsigned int max_size = 1 << (max_bits - 30);
+ bool sys_5level_pgtable = false;
unsigned int vm_size;
uint64_t tmp;
+#ifdef CONFIG_X86_64
+ /*
+ * Refer to function configure_5level_paging() for details.
+ */
+ sys_5level_pgtable = (native_read_cr4() & X86_CR4_LA57);
+#endif
+
+ /*
+ * If GPU supports 5-level page table, but system uses 4-level page table,
+ * then use 4-level page table on GPU
+ */
+ if (max_level == 4 && !sys_5level_pgtable) {
+ min_vm_size = 256 * 1024;
+ max_level = 3;
+ }
+
/* adjust vm size first */
if (amdgpu_vm_size != -1) {
vm_size = amdgpu_vm_size;
@@ -2405,6 +2422,9 @@ void amdgpu_vm_adjust_size(struct amdgpu_device *adev, uint32_t min_vm_size,
tmp = DIV_ROUND_UP(fls64(tmp) - 1, 9) - 1;
adev->vm_manager.num_level = min_t(unsigned int, max_level, tmp);
switch (adev->vm_manager.num_level) {
+ case 4:
+ adev->vm_manager.root_level = AMDGPU_VM_PDB3;
+ break;
case 3:
adev->vm_manager.root_level = AMDGPU_VM_PDB2;
break;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 15d757c016cbb..de53176a398dc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -185,9 +185,10 @@ struct amdgpu_bo_vm;
#define AMDGPU_VM_USE_CPU_FOR_COMPUTE (1 << 1)
/* VMPT level enumerate, and the hiberachy is:
- * PDB2->PDB1->PDB0->PTB
+ * PDB3->PDB2->PDB1->PDB0->PTB
*/
enum amdgpu_vm_level {
+ AMDGPU_VM_PDB3,
AMDGPU_VM_PDB2,
AMDGPU_VM_PDB1,
AMDGPU_VM_PDB0,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
index f794fb1cc06e6..c7a7d51080a87 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -51,6 +51,7 @@ static unsigned int amdgpu_vm_pt_level_shift(struct amdgpu_device *adev,
unsigned int level)
{
switch (level) {
+ case AMDGPU_VM_PDB3:
case AMDGPU_VM_PDB2:
case AMDGPU_VM_PDB1:
case AMDGPU_VM_PDB0:
--
2.51.0