[SDPA][HipDNN] ASM kernel loading and dispatch

[AnaghaRaoAMD]

Motivation

Implements ASM kernel loading and dispatch

Technical Details

Kernel Execution Implementation

Implements the complete kernel loading and dispatch pipeline for fwd_hd128_bf16_rtne.co ASM kernel:

1. SdpaKernelPlan - Kernel execution state (26 member variables):

   • Stores kernel module/function handles
   • Tensor UIDs and metadata (dims, strides)
   • Attention scale
   • execute(): Populates fmha_fwd_v3_args (656 bytes) and launches via hipModuleLaunchKernel()

2. SdpaKernelPlanBuilder - Plan creation:

   • buildPlan(): Loads kernel via hipModuleLoad() and extracts tensor metadata from graph
   • Parses Q/K/V tensor dimensions and strides from SDPA graph node
   • Computes attention scale (default: 1/√D_qk)

3. Key Implementation Details:

   • Kernel launch: HIP_LAUNCH_PARAM mechanism for large arg structures
   • Grid dimensions: [ceil(S_q/256), H_q, B]
   • Block dimensions: [512, 1, 1] (fixed for this kernel)
   • Strides: Converted from elements to bytes (stride × 2 for BF16)
   • Module lifecycle: Loaded on plan build, unloaded in destructor

Modified Files:

• src/SdpaKernelPlan.{hpp,cpp} - Execution implementation
• src/SdpaKernelPlanBuilder.cpp - Plan building with graph parsing

Test Plan

Verified with existing unit test infrastructure and integration tests

ninja install
 ./bin/sdpa_kernel_plugin_integration_tests
[==========] Running 2 tests from 2 test suites.
[----------] Global test environment set-up.
[----------] 1 test from IntegrationSdpaKernelNoEngines
[ RUN      ] IntegrationSdpaKernelNoEngines.BatchnormInferenceGraphBuildFails
[       OK ] IntegrationSdpaKernelNoEngines.BatchnormInferenceGraphBuildFails (1476 ms)
[----------] 1 test from IntegrationSdpaKernelNoEngines (1476 ms total)

[----------] 1 test from Smoke/IntegrationGpuSdpaFwdBf16
[ RUN      ] Smoke/IntegrationGpuSdpaFwdBf16.Correctness/0
[       OK ] Smoke/IntegrationGpuSdpaFwdBf16.Correctness/0 (1806 ms)
[----------] 1 test from Smoke/IntegrationGpuSdpaFwdBf16 (1806 ms total)

[----------] Global test environment tear-down
[==========] 2 tests from 2 test suites ran. (3283 ms total)
[  PASSED  ] 2 tests.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[DarylHawkinsAMD]

Looks good, just had one question inline

[jerehartAMD]

Looks good! I have a couple of comments, but I think the only one that's especially important to address is the move constructor one