[PATCH v11 11/20] gpu: nova-core: mm: Add MMU v3 page table types

[Joel Fernandes <joelagnelf@nvidia.com>]

Add page table entry and directory structures for MMU version 3
used by Hopper and later GPUs.

Cc: Nikola Djukic <ndjukic@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 drivers/gpu/nova-core/mm/pagetable.rs      |   1 +
 drivers/gpu/nova-core/mm/pagetable/ver2.rs |  10 +-
 drivers/gpu/nova-core/mm/pagetable/ver3.rs | 391 +++++++++++++++++++++
 3 files changed, 397 insertions(+), 5 deletions(-)
 create mode 100644 drivers/gpu/nova-core/mm/pagetable/ver3.rs

diff --git a/drivers/gpu/nova-core/mm/pagetable.rs b/drivers/gpu/nova-core/mm/pagetable.rs
index f6b184c9b8c8..9897818b3b07 100644
--- a/drivers/gpu/nova-core/mm/pagetable.rs
+++ b/drivers/gpu/nova-core/mm/pagetable.rs
@@ -9,6 +9,7 @@
 #![expect(dead_code)]
 
 pub(super) mod ver2;
+pub(super) mod ver3;
 
 use kernel::num::Bounded;
 
diff --git a/drivers/gpu/nova-core/mm/pagetable/ver2.rs b/drivers/gpu/nova-core/mm/pagetable/ver2.rs
index 8086f1e5abd8..37066688b5f1 100644
--- a/drivers/gpu/nova-core/mm/pagetable/ver2.rs
+++ b/drivers/gpu/nova-core/mm/pagetable/ver2.rs
@@ -59,11 +59,11 @@ pub(super) fn new(va: VirtualAddress) -> Self {
 impl VaLevelIndex for VirtualAddressV2 {
     fn level_index(&self, level: u64) -> u64 {
         match level {
-            0 => self.pde3_idx(),
-            1 => self.pde2_idx(),
-            2 => self.pde1_idx(),
-            3 => self.pde0_idx(),
-            4 => self.pt_idx(),
+            0 => self.pde3_idx().get(),
+            1 => self.pde2_idx().get(),
+            2 => self.pde1_idx().get(),
+            3 => self.pde0_idx().get(),
+            4 => self.pt_idx().get(),
             _ => 0,
         }
     }
diff --git a/drivers/gpu/nova-core/mm/pagetable/ver3.rs b/drivers/gpu/nova-core/mm/pagetable/ver3.rs
new file mode 100644
index 000000000000..2f9e762c4667
--- /dev/null
+++ b/drivers/gpu/nova-core/mm/pagetable/ver3.rs
@@ -0,0 +1,391 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! MMU v3 page table types for Hopper and later GPUs.
+//!
+//! This module defines MMU version 3 specific types (Hopper and later GPUs).
+//!
+//! Key differences from MMU v2:
+//! - Unified 40-bit address field for all apertures (v2 had separate sys/vid fields).
+//! - PCF (Page Classification Field) replaces separate privilege/RO/atomic/cache bits.
+//! - KIND field is 4 bits (not 8).
+//! - IS_PTE bit in PDE to support large pages directly.
+//! - No COMPTAGLINE field (compression handled differently in v3).
+//! - No separate ENCRYPTED bit.
+//!
+//! Bit field layouts derived from the NVIDIA OpenRM documentation:
+//! `open-gpu-kernel-modules/src/common/inc/swref/published/hopper/gh100/dev_mmu.h`
+
+#![expect(dead_code)]
+
+use kernel::bitfield;
+use kernel::num::Bounded;
+use kernel::prelude::*;
+use pin_init::Zeroable;
+
+use super::{
+    AperturePde,
+    AperturePte,
+    PageTableLevel,
+    VaLevelIndex, //
+};
+use crate::mm::{
+    Pfn,
+    VirtualAddress,
+    VramAddress, //
+};
+
+// Bounded to version 3 Pfn conversion.
+impl_pfn_bounded!(40);
+
+bitfield! {
+    /// MMU v3 57-bit virtual address layout.
+    pub(super) struct VirtualAddressV3(u64) {
+        /// Page offset [11:0].
+        11:0    offset;
+        /// PT index [20:12].
+        20:12   pt_idx;
+        /// PDE0 index [28:21].
+        28:21   pde0_idx;
+        /// PDE1 index [37:29].
+        37:29   pde1_idx;
+        /// PDE2 index [46:38].
+        46:38   pde2_idx;
+        /// PDE3 index [55:47].
+        55:47   pde3_idx;
+        /// PDE4 index [56].
+        56:56   pde4_idx;
+    }
+}
+
+impl VirtualAddressV3 {
+    /// Create a [`VirtualAddressV3`] from a [`VirtualAddress`].
+    pub(super) fn new(va: VirtualAddress) -> Self {
+        Self::from_raw(va.raw_u64())
+    }
+}
+
+impl VaLevelIndex for VirtualAddressV3 {
+    fn level_index(&self, level: u64) -> u64 {
+        match level {
+            0 => self.pde4_idx().get(),
+            1 => self.pde3_idx().get(),
+            2 => self.pde2_idx().get(),
+            3 => self.pde1_idx().get(),
+            4 => self.pde0_idx().get(),
+            5 => self.pt_idx().get(),
+            _ => 0,
+        }
+    }
+}
+
+/// PDE levels for MMU v3 (6-level hierarchy).
+pub(super) const PDE_LEVELS: &[PageTableLevel] = &[
+    PageTableLevel::Pdb,
+    PageTableLevel::L1,
+    PageTableLevel::L2,
+    PageTableLevel::L3,
+    PageTableLevel::L4,
+];
+
+/// PTE level for MMU v3.
+pub(super) const PTE_LEVEL: PageTableLevel = PageTableLevel::L5;
+
+/// Dual PDE level for MMU v3 (128-bit entries).
+pub(super) const DUAL_PDE_LEVEL: PageTableLevel = PageTableLevel::L4;
+
+bitfield! {
+    /// Page Classification Field for PTEs (5 bits) in MMU v3.
+    pub(in crate::mm) struct PtePcf(u8) {
+        /// Bypass L2 cache (0=cached, 1=bypass).
+        0:0     uncached;
+        /// Access counting disabled (0=enabled, 1=disabled).
+        1:1     acd;
+        /// Read-only access (0=read-write, 1=read-only).
+        2:2     read_only;
+        /// Atomics disabled (0=enabled, 1=disabled).
+        3:3     no_atomic;
+        /// Privileged access only (0=regular, 1=privileged).
+        4:4     privileged;
+    }
+}
+
+impl PtePcf {
+    /// Create PCF for read-write mapping (cached, no atomics, regular mode).
+    fn rw() -> Self {
+        Self::zeroed().with_no_atomic(true)
+    }
+
+    /// Create PCF for read-only mapping (cached, no atomics, regular mode).
+    fn ro() -> Self {
+        Self::zeroed().with_read_only(true).with_no_atomic(true)
+    }
+
+    /// Get the raw `u8` value.
+    fn raw_u8(&self) -> u8 {
+        self.into_raw()
+    }
+}
+
+impl From<Bounded<u64, 5>> for PtePcf {
+    fn from(val: Bounded<u64, 5>) -> Self {
+        Self::from_raw(u8::from(val))
+    }
+}
+
+impl From<PtePcf> for Bounded<u64, 5> {
+    fn from(pcf: PtePcf) -> Self {
+        Bounded::from_expr(u64::from(pcf.into_raw()) & 0x1F)
+    }
+}
+
+bitfield! {
+    /// Page Classification Field for PDEs (3 bits) in MMU v3.
+    ///
+    /// Controls Address Translation Services (ATS) and caching.
+    pub(in crate::mm) struct PdePcf(u8) {
+        /// Bypass L2 cache (0=cached, 1=bypass).
+        0:0     uncached;
+        /// ATS disabled (0=enabled, 1=disabled).
+        1:1     no_ats;
+    }
+}
+
+impl PdePcf {
+    /// Create PCF for cached mapping with ATS enabled (default).
+    fn cached() -> Self {
+        Self::zeroed()
+    }
+
+    /// Get the raw `u8` value.
+    fn raw_u8(&self) -> u8 {
+        self.into_raw()
+    }
+}
+
+impl From<Bounded<u64, 3>> for PdePcf {
+    fn from(val: Bounded<u64, 3>) -> Self {
+        Self::from_raw(u8::from(val))
+    }
+}
+
+impl From<PdePcf> for Bounded<u64, 3> {
+    fn from(pcf: PdePcf) -> Self {
+        Bounded::from_expr(u64::from(pcf.into_raw()) & 0x7)
+    }
+}
+
+bitfield! {
+    /// Page Table Entry for MMU v3.
+    pub(in crate::mm) struct Pte(u64) {
+        /// Entry is valid.
+        0:0     valid;
+        /// Memory aperture type.
+        2:1     aperture => AperturePte;
+        /// Page Classification Field.
+        7:3     pcf => PtePcf;
+        /// Surface kind (4 bits, 0x0=pitch, 0xF=invalid).
+        11:8    kind;
+        /// Physical frame number (for all apertures).
+        51:12   frame_number => Pfn;
+        /// Peer GPU ID for peer memory (0-7).
+        63:61   peer_id;
+    }
+}
+
+impl Pte {
+    /// Create a PTE from a `u64` value.
+    pub(super) fn new(val: u64) -> Self {
+        Self::from_raw(val)
+    }
+
+    /// Create a valid PTE for video memory.
+    pub(super) fn new_vram(frame: Pfn, writable: bool) -> Self {
+        let pcf = if writable { PtePcf::rw() } else { PtePcf::ro() };
+        Self::zeroed()
+            .with_valid(true)
+            .with_aperture(AperturePte::VideoMemory)
+            .with_pcf(pcf)
+            .with_frame_number(frame)
+    }
+
+    /// Create an invalid PTE.
+    pub(super) fn invalid() -> Self {
+        Self::zeroed()
+    }
+
+    /// Get the raw `u64` value.
+    pub(super) fn raw_u64(&self) -> u64 {
+        self.into_raw()
+    }
+}
+
+bitfield! {
+    /// Page Directory Entry for MMU v3 (Hopper+).
+    ///
+    /// Note: v3 uses a unified 40-bit address field (v2 had separate sys/vid address fields).
+    pub(in crate::mm) struct Pde(u64) {
+        /// Entry is a PTE (0=PDE, 1=large page PTE).
+        0:0     is_pte;
+        /// Memory aperture type.
+        2:1     aperture => AperturePde;
+        /// Page Classification Field (3 bits for PDE).
+        5:3     pcf => PdePcf;
+        /// Table frame number (40-bit unified address).
+        51:12   table_frame => Pfn;
+    }
+}
+
+impl Pde {
+    /// Create a PDE from a `u64` value.
+    pub(super) fn new(val: u64) -> Self {
+        Self::from_raw(val)
+    }
+
+    /// Create a valid PDE pointing to a page table in video memory.
+    pub(super) fn new_vram(table_pfn: Pfn) -> Self {
+        Self::zeroed()
+            .with_is_pte(false)
+            .with_aperture(AperturePde::VideoMemory)
+            .with_table_frame(table_pfn)
+    }
+
+    /// Create an invalid PDE.
+    pub(super) fn invalid() -> Self {
+        Self::zeroed().with_aperture(AperturePde::Invalid)
+    }
+
+    /// Check if this PDE is valid.
+    pub(super) fn is_valid(&self) -> bool {
+        self.aperture() != AperturePde::Invalid
+    }
+
+    /// Get the VRAM address of the page table.
+    pub(super) fn table_vram_address(&self) -> VramAddress {
+        debug_assert!(
+            self.aperture() == AperturePde::VideoMemory,
+            "table_vram_address called on non-VRAM PDE (aperture: {:?})",
+            self.aperture()
+        );
+        VramAddress::from(self.table_frame())
+    }
+
+    /// Get the raw `u64` value.
+    pub(super) fn raw_u64(&self) -> u64 {
+        self.into_raw()
+    }
+}
+
+bitfield! {
+    /// Big Page Table pointer in Dual PDE (MMU v3).
+    ///
+    /// 64-bit lower word of the 128-bit Dual PDE.
+    pub(super) struct DualPdeBig(u64) {
+        /// Entry is a PTE (for large pages).
+        0:0     is_pte;
+        /// Memory aperture type.
+        2:1     aperture => AperturePde;
+        /// Page Classification Field.
+        5:3     pcf => PdePcf;
+        /// Table frame (table address 256-byte aligned).
+        51:8    table_frame;
+    }
+}
+
+impl DualPdeBig {
+    /// Create a big page table pointer from a `u64` value.
+    fn new(val: u64) -> Self {
+        Self::from_raw(val)
+    }
+
+    /// Create an invalid big page table pointer.
+    fn invalid() -> Self {
+        Self::zeroed().with_aperture(AperturePde::Invalid)
+    }
+
+    /// Create a valid big PDE pointing to a page table in video memory.
+    fn new_vram(table_addr: VramAddress) -> Result<Self> {
+        // Big page table addresses must be 256-byte aligned (shift 8).
+        if table_addr.raw_u64() & 0xFF != 0 {
+            return Err(EINVAL);
+        }
+
+        let table_frame = Bounded::from_expr(table_addr.raw_u64() >> 8);
+        Ok(Self::zeroed()
+            .with_is_pte(false)
+            .with_aperture(AperturePde::VideoMemory)
+            .with_table_frame(table_frame))
+    }
+
+    /// Check if this big PDE is valid.
+    fn is_valid(&self) -> bool {
+        self.aperture() != AperturePde::Invalid
+    }
+
+    /// Get the VRAM address of the big page table.
+    fn table_vram_address(&self) -> VramAddress {
+        debug_assert!(
+            self.aperture() == AperturePde::VideoMemory,
+            "table_vram_address called on non-VRAM DualPdeBig (aperture: {:?})",
+            self.aperture()
+        );
+        VramAddress::new(self.table_frame().get() << 8)
+    }
+
+    /// Get the raw `u64` value.
+    pub(super) fn raw_u64(&self) -> u64 {
+        self.into_raw()
+    }
+}
+
+/// Dual PDE at Level 4 for MMU v3 - 128-bit entry.
+///
+/// Contains both big (64KB) and small (4KB) page table pointers:
+/// - Lower 64 bits: Big Page Table pointer.
+/// - Upper 64 bits: Small Page Table pointer.
+///
+/// ## Note
+///
+/// The big and small page table pointers have different address layouts:
+/// - Big address = field value << 8 (256-byte alignment).
+/// - Small address = field value << 12 (4KB alignment).
+///
+/// This is why `DualPdeBig` is a separate type from `Pde`.
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub(in crate::mm) struct DualPde {
+    /// Big Page Table pointer.
+    pub(super) big: DualPdeBig,
+    /// Small Page Table pointer.
+    pub(super) small: Pde,
+}
+
+// SAFETY: Both `DualPdeBig` and `Pde` fields are `Zeroable` (bitfield types are Zeroable).
+unsafe impl Zeroable for DualPde {}
+
+impl DualPde {
+    /// Create a dual PDE from raw 128-bit value (two `u64`s).
+    pub(super) fn new(big: u64, small: u64) -> Self {
+        Self {
+            big: DualPdeBig::new(big),
+            small: Pde::new(small),
+        }
+    }
+
+    /// Create a dual PDE with only the small page table pointer set.
+    pub(super) fn new_small(table_pfn: Pfn) -> Self {
+        Self {
+            big: DualPdeBig::invalid(),
+            small: Pde::new_vram(table_pfn),
+        }
+    }
+
+    /// Check if the small page table pointer is valid.
+    pub(super) fn has_small(&self) -> bool {
+        self.small.is_valid()
+    }
+
+    /// Check if the big page table pointer is valid.
+    fn has_big(&self) -> bool {
+        self.big.is_valid()
+    }
+}
-- 
2.34.1