Re: [PATCH v10 21/21] gpu: nova-core: Use runtime BAR1 size instead of hardcoded 256MB

Eliot Courtney
2026-04-02T12:27:08Z

On Wed Apr 1, 2026 at 6:20 AM JST, Joel Fernandes wrote:
> From: Zhi Wang <zhiw@nvidia.com>
>
> Remove the hardcoded BAR1_SIZE = SZ_256M constant. On GPUs like L40 the
> BAR1 aperture is larger than 256MB; using a hardcoded size prevents large
> BAR1 from working and mapping it would fail.
>
> Signed-off-by: Zhi Wang <zhiw@nvidia.com>
> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
> ---
> drivers/gpu/nova-core/driver.rs | 8 ++------
> drivers/gpu/nova-core/gpu.rs | 7 +------
> 2 files changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
> index b1aafaff0cee..6f95f8672158 100644
> --- a/drivers/gpu/nova-core/driver.rs
> +++ b/drivers/gpu/nova-core/driver.rs
> @@ -13,10 +13,7 @@
> Vendor, //
> },
> prelude::*,
> - sizes::{
> - SZ_16M,
> - SZ_256M, //
> - },
> + sizes::SZ_16M,
> sync::{
> atomic::{
> Atomic,
> @@ -40,7 +37,6 @@ pub(crate) struct NovaCore {
> }
>
> const BAR0_SIZE: usize = SZ_16M;
> -pub(crate) const BAR1_SIZE: usize = SZ_256M;
>
> // For now we only support Ampere which can use up to 47-bit DMA addresses.
> //
> @@ -51,7 +47,7 @@ pub(crate) struct NovaCore {
> const GPU_DMA_BITS: u32 = 47;
>
> pub(crate) type Bar0 = pci::Bar<BAR0_SIZE>;
> -pub(crate) type Bar1 = pci::Bar<BAR1_SIZE>;
> +pub(crate) type Bar1 = pci::Bar;
>
> kernel::pci_device_table!(
> PCI_TABLE,
> diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
> index 8206ec015b26..ba6f1f6f0485 100644
> --- a/drivers/gpu/nova-core/gpu.rs
> +++ b/drivers/gpu/nova-core/gpu.rs
> @@ -353,16 +353,11 @@ pub(crate) fn run_selftests(
>
> #[cfg(CONFIG_NOVA_MM_SELFTESTS)]
> fn run_mm_selftests(self: Pin<&mut Self>, pdev: &pci::Device<device::Bound>) -> Result {
> - use crate::driver::BAR1_SIZE;
> -
> // PRAMIN aperture self-tests.
> crate::mm::pramin::run_self_test(pdev.as_ref(), self.mm.pramin(), self.spec.chipset)?;
>
> // BAR1 self-tests.
> - let bar1 = Arc::pin_init(
> - pdev.iomap_region_sized::<BAR1_SIZE>(1, c"nova-core/bar1"),
> - GFP_KERNEL,
> - )?;
> + let bar1 = Arc::pin_init(pdev.iomap_region(1, c"nova-core/bar1"), GFP_KERNEL)?;
> let bar1_access = bar1.access(pdev.as_ref())?;
>
> crate::mm::bar_user::run_self_test(

Can we move this directly after patch 17 which adds the fixed bar1? Or
alternatively fold it in while preserving Zhi's attribution (I am not
sure what the conventional method for this is).