FAILED: Patch "drm/amdgpu: Use 5-level paging if gmc support 57-bit VA" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 3b948dd0366a0b64c02e4ed1aefdf7825942e803 Mon Sep 17 00:00:00 2001
From: Philip Yang <[email protected]>
Date: Tue, 27 Jan 2026 13:52:33 -0500
Subject: [PATCH] drm/amdgpu: Use 5-level paging if gmc support 57-bit VA
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Regardless if CPU enable 5-level paging, GPU vm use 5-level paging if gmc init with 57-bit address space support, because

ARM64 4-level paging support 48-bit VA, x86 and GPU 4-level paging support 47-bit VA, require 5-level paging on GPU to support ARM64.

NPA address space 52-bit mapping on NPA GPU VM require 5-level paging.

Debugger trap get device snapshot expect LDS and Scratch base, limit above 57-bit, which is set only for 5-level paging.

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 17 -----------------
 1 file changed, 17 deletions(-)

index 6a2ea200d90c8..31383583fc682 100644
@@ -2360,26 +2360,9 @@ 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;

2.51.0