Introduce a trait for 128-bit Dual Page Directory Entries. The `read()`/`write()` helpers issue two 64-bit accesses through a `PraminWindow` to load/store the 128-bit value.
Signed-off-by: Joel Fernandes <[email protected]> --- drivers/gpu/nova-core/mm/pagetable.rs | 34 +++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/drivers/gpu/nova-core/mm/pagetable.rs b/drivers/gpu/nova-core/mm/pagetable.rs index 1c94b3afa8b2..7ea090024d91 100644 --- a/drivers/gpu/nova-core/mm/pagetable.rs +++ b/drivers/gpu/nova-core/mm/pagetable.rs @@ -159,6 +159,40 @@ fn is_valid_vram(&self) -> bool { } } +/// Operations on Dual Page Directory Entries (128-bit `DualPde`s). +pub(super) trait DualPdeOps: Copy + core::fmt::Debug { + /// Create a `DualPde` from raw 128-bit value (two `u64`s). + fn from_raw(big: u64, small: u64) -> Self; + + /// Create a `DualPde` with only the small page table pointer set. + fn new_small(table_pfn: Pfn) -> Self; + + /// Check if the small page table pointer is valid. + fn has_small(&self) -> bool; + + /// Get the small page table VRAM address. + fn small_vram_address(&self) -> VramAddress; + + /// Get the raw `u64` value of the big PDE. + fn big_raw_u64(&self) -> u64; + + /// Get the raw `u64` value of the small PDE. + fn small_raw_u64(&self) -> u64; + + /// Read a dual PDE (128-bit) from VRAM. + fn read(window: &mut pramin::PraminWindow<'_>, addr: VramAddress) -> Result<Self> { + let lo = window.try_read64(addr)?; + let hi = window.try_read64(addr + 8)?; + Ok(Self::from_raw(lo, hi)) + } + + /// Write this dual PDE (128-bit) to VRAM. + fn write(&self, window: &mut pramin::PraminWindow<'_>, addr: VramAddress) -> Result { + window.try_write64(addr, self.big_raw_u64())?; + window.try_write64(addr + 8, self.small_raw_u64()) + } +} + /// Memory aperture for Page Table Entries (`PTE`s). /// /// Determines which memory region the `PTE` points to. -- 2.34.1
