Reviewed-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
Tested-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
On Tue, Aug 01, 2023 at 04:05:21PM -0700, Sean Christopherson wrote:
> Move the check that a vGPU is attached from is_2MB_gtt_possible() all the
> way up to shadow_ppgtt_mm() to avoid unnecessary work, and to make it more
> obvious that a future cleanup of is_2MB_gtt_possible() isn't introducing a
> bug.
>
> is_2MB_gtt_possible() has only one caller, ppgtt_populate_shadow_entry(),
> and all paths in ppgtt_populate_shadow_entry() eventually check for
> attachment by way of intel_gvt_dma_map_guest_page().
>
> And of the paths that lead to ppgtt_populate_shadow_entry(),
> shadow_ppgtt_mm() is the only one that doesn't already check for
> INTEL_VGPU_STATUS_ACTIVE or INTEL_VGPU_STATUS_ATTACHED.
>
> workload_thread() <= pick_next_workload() => INTEL_VGPU_STATUS_ACTIVE
> |
> -> dispatch_workload()
> |
> |-> prepare_workload()
> |
> -> intel_vgpu_sync_oos_pages()
> | |
> | |-> ppgtt_set_guest_page_sync()
> | |
> | |-> sync_oos_page()
> | |
> | |-> ppgtt_populate_shadow_entry()
> |
> |-> intel_vgpu_flush_post_shadow()
> |
> 1: |-> ppgtt_handle_guest_write_page_table()
> |
> |-> ppgtt_handle_guest_entry_add()
> |
> 2: | -> ppgtt_populate_spt_by_guest_entry()
> | |
> | |-> ppgtt_populate_spt()
> | |
> | |-> ppgtt_populate_shadow_entry()
> | |
> | |-> ppgtt_populate_spt_by_guest_entry() [see 2]
> |
> |-> ppgtt_populate_shadow_entry()
>
> kvmgt_page_track_write() <= KVM callback => INTEL_VGPU_STATUS_ATTACHED
> |
> |-> intel_vgpu_page_track_handler()
> |
> |-> ppgtt_write_protection_handler()
> |
> |-> ppgtt_handle_guest_write_page_table_bytes()
> |
> |-> ppgtt_handle_guest_write_page_table() [see 1]
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
>
> v4.1:
>
> - Actually make the code do what the changelog says. [Yan]
> - Fix a typo in the changelog. [Yan]
>
> drivers/gpu/drm/i915/gvt/gtt.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
> index 5426a27c1b71..de6a484090d7 100644
> --- a/drivers/gpu/drm/i915/gvt/gtt.c
> +++ b/drivers/gpu/drm/i915/gvt/gtt.c
> @@ -1163,8 +1163,6 @@ static int is_2MB_gtt_possible(struct intel_vgpu *vgpu,
> if (!HAS_PAGE_SIZES(vgpu->gvt->gt->i915, I915_GTT_PAGE_SIZE_2M))
> return 0;
>
> - if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
> - return -EINVAL;
> pfn = gfn_to_pfn(vgpu->vfio_device.kvm, ops->get_pfn(entry));
> if (is_error_noslot_pfn(pfn))
> return -EINVAL;
> @@ -1827,6 +1825,9 @@ static int shadow_ppgtt_mm(struct intel_vgpu_mm *mm)
> if (mm->ppgtt_mm.shadowed)
> return 0;
>
> + if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status))
> + return -EINVAL;
> +
> mm->ppgtt_mm.shadowed = true;
>
> for (index = 0; index < ARRAY_SIZE(mm->ppgtt_mm.guest_pdps); index++) {
>
> base-commit: 03e8f77e106ba1d2fd980f8b38339dad33333a07
> --
> 2.41.0.585.gd2178a4bd4-goog
>
