Merge pull request #1218 from hermit-os/virtio-bugfix

fix(virtio-pci): `next_ptr` + `cfg_ptr` offsets

src/drivers/virtio/transport/pci.rs

@@ -702,9 +702,10 @@ impl NotifCfg {
 
 		// Assumes the cap_len is a multiple of 8
 		// This read MIGHT be slow, as it does NOT ensure 32 bit alignment.
-		let notify_off_multiplier = cap.device.read_register(
-			u16::try_from(cap.origin.cfg_ptr).unwrap() + u16::from(cap.origin.cap_struct.cap_len),
-		);
+		let notify_off_multiplier_ptr =
+			cap.origin.cfg_ptr + u32::try_from(mem::size_of::<PciCapRaw>()).unwrap();
+		let notify_off_multiplier_ptr = u16::try_from(notify_off_multiplier_ptr).unwrap();
+		let notify_off_multiplier = cap.device.read_register(notify_off_multiplier_ptr);
 
 		// define base memory address from which the actual Queue Notify address can be derived via
 		// base_addr + queue_notify_off * notify_off_multiplier.
@@ -921,8 +922,8 @@ impl PciCfgAlt {
 // #[repr(C)]
 // struct PciCap64 {
 //    pci_cap: PciCap,
-//    offset_high: u32,
-//    length_high: u32
+//    offset_hi: u32,
+//    length_hi: u32
 pub struct ShMemCfg {
 	mem_addr: VirtMemAddr,
 	length: MemLen,
@@ -947,24 +948,25 @@ impl ShMemCfg {
 
 		// Assumes the cap_len is a multiple of 8
 		// This read MIGHT be slow, as it does NOT ensure 32 bit alignment.
-		let offset_high = cap.device.read_register(
-			u16::try_from(cap.origin.cfg_ptr).unwrap() + u16::from(cap.origin.cap_struct.cap_len),
-		);
+		let offset_hi_ptr =
+			cap.origin.cfg_ptr + u32::try_from(mem::size_of::<PciCapRaw>()).unwrap();
+		let offset_hi_ptr = u16::try_from(offset_hi_ptr).unwrap();
+		let offset_hi = cap.device.read_register(offset_hi_ptr);
 
 		// Create 64 bit offset from high and low 32 bit values
 		let offset =
-			MemOff::from((u64::from(offset_high) << 32) ^ u64::from(cap.origin.cap_struct.offset));
+			MemOff::from((u64::from(offset_hi) << 32) ^ u64::from(cap.origin.cap_struct.offset));
 
 		// Assumes the cap_len is a multiple of 8
 		// This read MIGHT be slow, as it does NOT ensure 32 bit alignment.
-		let length_high = cap.device.read_register(
-			u16::try_from(cap.origin.cfg_ptr).unwrap()
-				+ u16::from(cap.origin.cap_struct.cap_len + 4),
-		);
+		let length_hi_ptr = cap.origin.cfg_ptr
+			+ u32::try_from(mem::size_of::<PciCapRaw>() + mem::size_of::<u32>()).unwrap();
+		let length_hi_ptr = u16::try_from(length_hi_ptr).unwrap();
+		let length_hi = cap.device.read_register(length_hi_ptr);
 
 		// Create 64 bit length from high and low 32 bit values
 		let length =
-			MemLen::from((u64::from(length_high) << 32) ^ u64::from(cap.origin.cap_struct.length));
+			MemLen::from((u64::from(length_hi) << 32) ^ u64::from(cap.origin.cap_struct.length));
 
 		let virt_addr_raw = cap.bar.mem_addr + offset;
 		let raw_ptr = ptr::with_exposed_provenance_mut::<u8>(virt_addr_raw.into());
@@ -1118,6 +1120,7 @@ fn read_caps(
 
 		let mut iter = bars.iter();
 
+		let cfg_ptr = next_ptr;
 		// Set next pointer for next iteration of `caplist.
 		next_ptr = u32::from(cap_raw.cap_next);
 
@@ -1151,7 +1154,7 @@ fn read_caps(
 					length: MemLen::from(cap_raw.length),
 					device: *device,
 					origin: Origin {
-						cfg_ptr: next_ptr,
+						cfg_ptr,
 						dev_id: device_id,
 						cap_struct: cap_raw,
 					},