drm/amd/amdgpu:save psp ring wptr to avoid attack

[ Upstream commit 2370eba9f552eaae3d8aa1f70b8e9eec5c560f9e ]

[Why]
When some tools performing psp mailbox attack, the readback value
of register can be a random value which may break psp.

[How]
Use a psp wptr cache machanism to aovid the change made by attack.

v2: unify change and add detailed reason

Signed-off-by: Victor Zhao <Victor.Zhao@amd.com>
Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.h
index 919d2fb..60b7563 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_psp.h
@@ -73,6 +73,7 @@ struct psp_ring
        uint64_t                        ring_mem_mc_addr;
        void                            *ring_mem_handle;
        uint32_t                        ring_size;
+       uint32_t                        ring_wptr;
 };
 
 /* More registers may will be supported */

diff --git a/drivers/gpu/drm/amd/amdgpu/psp_v11_0.c b/drivers/gpu/drm/amd/amdgpu/psp_v11_0.c
index 6c5d961..cb764b5 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/psp_v11_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/psp_v11_0.c
@@ -732,7 +732,7 @@ static uint32_t psp_v11_0_ring_get_wptr(struct psp_context *psp)
        struct amdgpu_device *adev = psp->adev;
 
        if (amdgpu_sriov_vf(adev))
-               data = RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_102);
+               data = psp->km_ring.ring_wptr;
        else
                data = RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_67);
 
@@ -746,6 +746,7 @@ static void psp_v11_0_ring_set_wptr(struct psp_context *psp, uint32_t value)
        if (amdgpu_sriov_vf(adev)) {
                WREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_102, value);
                WREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_101, GFX_CTRL_CMD_ID_CONSUME_CMD);
+               psp->km_ring.ring_wptr = value;
        } else
                WREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_67, value);
 }

diff --git a/drivers/gpu/drm/amd/amdgpu/psp_v3_1.c b/drivers/gpu/drm/amd/amdgpu/psp_v3_1.c
index f2e725f..908664a 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/psp_v3_1.c
+++ b/drivers/gpu/drm/amd/amdgpu/psp_v3_1.c
@@ -379,7 +379,7 @@ static uint32_t psp_v3_1_ring_get_wptr(struct psp_context *psp)
        struct amdgpu_device *adev = psp->adev;
 
        if (amdgpu_sriov_vf(adev))
-               data = RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_102);
+               data = psp->km_ring.ring_wptr;
        else
                data = RREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_67);
        return data;
@@ -394,6 +394,7 @@ static void psp_v3_1_ring_set_wptr(struct psp_context *psp, uint32_t value)
                /* send interrupt to PSP for SRIOV ring write pointer update */
                WREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_101,
                        GFX_CTRL_CMD_ID_CONSUME_CMD);
+               psp->km_ring.ring_wptr = value;
        } else
                WREG32_SOC15(MP0, 0, mmMP0_SMN_C2PMSG_67, value);
 }