On Thu Oct 16, 2025 at 4:49 AM JST, Daniel del Castillo wrote: > This patch solves the existing mentions of COHA, a task > in the Nova task list about improving the `CoherentAllocation` API. > I confirmed by talking to Alexandre Courbot, that the reading/writing > methods in `CoherentAllocation` can never be safe, so > this patch doesn't actually change `CoherentAllocation`, but rather > tries to solve the existing references to [COHA].
This mention of background discussions should be in the comment part of your commit (below the `---`). > > Signed-off-by: Daniel del Castillo <[email protected]> > --- > drivers/gpu/nova-core/dma.rs | 20 ++--- > drivers/gpu/nova-core/firmware/fwsec.rs | 104 ++++++++++-------------- > 2 files changed, 50 insertions(+), 74 deletions(-) > > diff --git a/drivers/gpu/nova-core/dma.rs b/drivers/gpu/nova-core/dma.rs > index 94f44bcfd748..639a99cf72c4 100644 > --- a/drivers/gpu/nova-core/dma.rs > +++ b/drivers/gpu/nova-core/dma.rs > @@ -25,21 +25,11 @@ pub(crate) fn new(dev: &device::Device<device::Bound>, > len: usize) -> Result<Sel > } > > pub(crate) fn from_data(dev: &device::Device<device::Bound>, data: > &[u8]) -> Result<Self> { > - Self::new(dev, data.len()).map(|mut dma_obj| { > - // TODO[COHA]: replace with `CoherentAllocation::write()` once > available. > - // SAFETY: > - // - `dma_obj`'s size is at least `data.len()`. > - // - We have just created this object and there is no other user > at this stage. > - unsafe { > - core::ptr::copy_nonoverlapping( > - data.as_ptr(), > - dma_obj.dma.start_ptr_mut(), > - data.len(), > - ); > - } > - > - dma_obj > - }) > + let mut dma_obj = Self::new(dev, data.len())?; > + // SAFETY: We have just created this object and there is no other > user at this stage. > + unsafe { dma_obj.write(data, 0)? }; > + > + Ok(dma_obj) Can you preserve the use of `map`? This removes the need for the temporary variable. <snip> > /// The FWSEC microcode, extracted from the BIOS and to be run on the GSP > falcon. > @@ -260,32 +245,38 @@ fn new_fwsec(dev: &Device<device::Bound>, bios: &Vbios, > cmd: FwsecCommand) -> Re > > // Find the DMEM mapper section in the firmware. > for i in 0..hdr.entry_count as usize { > - let app: &FalconAppifV1 = > // SAFETY: we have exclusive access to `dma_object`. > - unsafe { > + let app: &FalconAppifV1 = unsafe { > transmute( > &dma_object, > - hdr_offset + hdr.header_size as usize + i * > hdr.entry_size as usize > + hdr_offset + hdr.header_size as usize + i * > hdr.entry_size as usize, > ) > }?; > > if app.id != NVFW_FALCON_APPIF_ID_DMEMMAPPER { > continue; > } > + let dmem_base = app.dmem_base; > > // SAFETY: we have exclusive access to `dma_object`. > let dmem_mapper: &mut FalconAppifDmemmapperV3 = unsafe { > - transmute_mut( > - &mut dma_object, > - (desc.imem_load_size + app.dmem_base) as usize, > - ) > + transmute_mut(&mut dma_object, (desc.imem_load_size + > dmem_base) as usize) > }?; > > + dmem_mapper.init_cmd = match cmd { > + FwsecCommand::Frts { > + frts_addr: _, > + frts_size: _, Can the `{ .. }` syntax be used here? > + } => NVFW_FALCON_APPIF_DMEMMAPPER_CMD_FRTS, > + FwsecCommand::Sb => NVFW_FALCON_APPIF_DMEMMAPPER_CMD_SB, > + }; > + let cmd_in_buffer_offset = dmem_mapper.cmd_in_buffer_offset; > + > // SAFETY: we have exclusive access to `dma_object`. > let frts_cmd: &mut FrtsCmd = unsafe { > transmute_mut( > &mut dma_object, > - (desc.imem_load_size + dmem_mapper.cmd_in_buffer_offset) > as usize, > + (desc.imem_load_size + cmd_in_buffer_offset) as usize, > ) > }?; > > @@ -296,24 +287,19 @@ fn new_fwsec(dev: &Device<device::Bound>, bios: &Vbios, > cmd: FwsecCommand) -> Re > size: 0, > flags: 2, > }; > - > - dmem_mapper.init_cmd = match cmd { > - FwsecCommand::Frts { > - frts_addr, > - frts_size, > - } => { > - frts_cmd.frts_region = FrtsRegion { > - ver: 1, > - hdr: size_of::<FrtsRegion>() as u32, > - addr: (frts_addr >> 12) as u32, > - size: (frts_size >> 12) as u32, > - ftype: NVFW_FRTS_CMD_REGION_TYPE_FB, > - }; > - > - NVFW_FALCON_APPIF_DMEMMAPPER_CMD_FRTS > - } > - FwsecCommand::Sb => NVFW_FALCON_APPIF_DMEMMAPPER_CMD_SB, > - }; > + if let FwsecCommand::Frts { > + frts_addr, > + frts_size, > + } = cmd > + { > + frts_cmd.frts_region = FrtsRegion { > + ver: 1, > + hdr: size_of::<FrtsRegion>() as u32, > + addr: (frts_addr >> 12) as u32, > + size: (frts_size >> 12) as u32, > + ftype: NVFW_FRTS_CMD_REGION_TYPE_FB, > + }; > + } I liked that the original code updated both `init_cmd` and `frts_region` in the same match block. I understand it might be difficult to preserve due to the borrowing rules, but can you try to preserve it if that's possible at all?
