Now have a so-called mapper

Cargo.lock

@@ -2,6 +2,12 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "accessor"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd8b2abd55bf1f9cffbf00fd594566c51a9d31402553284920c1309ca8351086"
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.3"
@@ -66,6 +72,12 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
 
+[[package]]
+name = "bit_field"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc827186963e592360843fb5ba4b973e145841266c1357f7180c43526f2e5b61"
+
 [[package]]
 name = "clap"
 version = "4.5.9"
@@ -97,7 +109,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.71",
 ]
 
 [[package]]
@@ -196,6 +208,18 @@ dependencies = [
  "eyre",
  "log",
  "pci-driver",
+ "xhci",
+]
+
+[[package]]
+name = "num-derive"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "876a53fff98e03a936a674b29568b0e605f06b29372c2489ff4de23f1949743d"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
 ]
 
 [[package]]
@@ -213,6 +237,12 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "pci-driver"
 version = "0.1.4"
@@ -276,6 +306,17 @@ version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.71"
@@ -371,3 +412,16 @@ name = "windows_x86_64_msvc"
 version = "0.52.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
+[[package]]
+name = "xhci"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09f3f0483969259f2adb6524054400d94ac352e59fa37da6c6ca3b9b3d83ff83"
+dependencies = [
+ "accessor",
+ "bit_field",
+ "num-derive",
+ "num-traits",
+ "paste",
+]

Cargo.toml

@@ -9,3 +9,4 @@ env_logger = "0.11.3"
 eyre = "0.6.12"
 log = "0.4.22"
 pci-driver = "0.1.4"
+xhci = "0.9.2"

src/main.rs

@@ -1,3 +1,7 @@
+mod pci;
+
+use std::sync::Arc;
+
 use clap::Parser;
 use pci_driver::{backends::vfio::VfioPciDevice, device::PciDevice};
 
@@ -16,28 +20,17 @@ fn main() -> eyre::Result<()> {
     env_logger::init();
     let args = Args::parse();
 
-    let device = VfioPciDevice::open(&args.device)?;
+    let device = Arc::new(VfioPciDevice::open(&args.device)?);
 
     if args.reset {
         device.reset()?;
     }
 
-    let config = device.config();
+    let registers = crate::pci::load_registers(device)?;
-    // This library got the order backwards...
-    let class = (
-        config.class_code().programming_interface().read()?,
-        config.class_code().sub_class_code().read()?,
-        config.class_code().base_class_code().read()?,
-    );
-    println!("{:?}", class);
-    if class != (0x0c, 0x03, 0x30) {
-        eyre::bail!("Device is not xHCI controller!");
-    }
 
     log::info!(
-        "Found PCIe device {:04x}:{:04x}",
+        "xHCI version: {:04x}",
-        config.vendor_id().read()?,
+        registers.capability.hciversion.read_volatile().get()
-        config.device_id().read()?
     );
 
     Ok(())

src/pci.rs

@@ -0,0 +1,74 @@
+use std::{num::NonZeroUsize, sync::Arc};
+
+use eyre::OptionExt;
+use pci_driver::{
+    backends::vfio::VfioPciDevice,
+    device::PciDevice,
+    regions::{MappedOwningPciRegion, PciRegion},
+};
+use xhci::Registers;
+
+#[derive(Clone)]
+pub struct PciMapper {
+    pub device: Arc<VfioPciDevice>,
+    pub mapped_region: Arc<MappedOwningPciRegion>,
+    pub phys_base: usize,
+}
+
+impl xhci::accessor::Mapper for PciMapper {
+    unsafe fn map(&mut self, phys_start: usize, bytes: usize) -> std::num::NonZeroUsize {
+        log::trace!("Map {:#018x}: {:#x} bytes", phys_start, bytes);
+        if phys_start < self.phys_base
+            || phys_start - self.phys_base + bytes > self.mapped_region.len()
+        {
+            panic!("Tried to access invalid address");
+        }
+
+        NonZeroUsize::try_from(
+            (self.mapped_region.as_ptr() as usize) + (phys_start - self.phys_base),
+        )
+        .unwrap()
+    }
+
+    fn unmap(&mut self, virt_start: usize, bytes: usize) {
+        log::trace!("Unmap {:#018x}: {:#x} bytes", virt_start, bytes);
+        // no-op, we mapped the entire BAR 0 anyway
+    }
+}
+
+pub fn load_registers(device: Arc<VfioPciDevice>) -> eyre::Result<Registers<PciMapper>> {
+    let config = device.config();
+    let class = config.read_le_u32(0x08)? >> 8;
+    if class != 0x0c_03_30 {
+        eyre::bail!("Device is not xHCI controller!");
+    }
+
+    log::info!(
+        "Found xHCI controller device {:04x}:{:04x}",
+        config.vendor_id().read()?,
+        config.device_id().read()?
+    );
+
+    let mut bar = [0u8; 8];
+    device.config().read_bytes(0x10, &mut bar)?;
+    let phys_base = u64::from_le_bytes(bar) & 0xffff_fff8;
+
+    log::debug!("BAR physical base: {:#018x}", phys_base);
+
+    let region = device.bar(0).ok_or_eyre("Device does not have BAR 0")?;
+    let mapped_region =
+        Arc::new(region.map(0..region.len(), pci_driver::regions::Permissions::ReadWrite)?);
+
+    log::debug!(
+        "BAR virtual base: {:#018x}",
+        mapped_region.as_ptr() as usize
+    );
+
+    let mapper = PciMapper {
+        device,
+        mapped_region,
+        phys_base: phys_base.try_into()?,
+    };
+
+    unsafe { Ok(Registers::new(phys_base as usize, mapper)) }
+}