pci: Detect BAR reprogramming

Based on the value being written to the BAR, the implementation can
now detect if the BAR is being moved to another address. If that is the
case, it invokes move_bar() function from the DeviceRelocation trait.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

pci/src/bus.rs

@@ -9,6 +9,7 @@ use crate::device::{DeviceRelocation, Error as PciDeviceError, PciDevice};
 use byteorder::{ByteOrder, LittleEndian};
 use devices::BusDevice;
 use std;
+use std::ops::DerefMut;
 use std::sync::Arc;
 use std::sync::Mutex;
 use vm_memory::{Address, GuestAddress, GuestUsize};
@@ -75,7 +76,7 @@ pub struct PciBus {
     /// Devices attached to this bus.
     /// Device 0 is host bridge.
     devices: Vec<Arc<Mutex<dyn PciDevice>>>,
-    _device_reloc: Arc<dyn DeviceRelocation>,
+    device_reloc: Arc<dyn DeviceRelocation>,
 }
 
 impl PciBus {
@@ -86,7 +87,7 @@ impl PciBus {
 
         PciBus {
             devices,
-            _device_reloc: device_reloc,
+            device_reloc,
         }
     }
 
@@ -185,10 +186,26 @@ impl PciConfigIo {
             return;
         }
 
-        if let Some(d) = self.pci_bus.lock().unwrap().devices.get(device) {
-            d.lock()
-                .unwrap()
-                .write_config_register(register, offset, data);
+        let pci_bus = self.pci_bus.lock().unwrap();
+        if let Some(d) = pci_bus.devices.get(device) {
+            let mut device = d.lock().unwrap();
+
+            // Find out if one of the device's BAR is being reprogrammed
+            let bar_reprog_params = device.detect_bar_reprogramming(register, data);
+
+            // Update the register value
+            device.write_config_register(register, offset, data);
+
+            // Reprogram the BAR if needed
+            if let Some(params) = bar_reprog_params {
+                pci_bus.device_reloc.move_bar(
+                    params.old_base,
+                    params.new_base,
+                    params.len,
+                    device.deref_mut(),
+                    params.region_type,
+                );
+            }
         }
     }
 
@@ -285,10 +302,26 @@ impl PciConfigMmio {
             return;
         }
 
-        if let Some(d) = self.pci_bus.lock().unwrap().devices.get(device) {
-            d.lock()
-                .unwrap()
-                .write_config_register(register, offset, data);
+        let pci_bus = self.pci_bus.lock().unwrap();
+        if let Some(d) = pci_bus.devices.get(device) {
+            let mut device = d.lock().unwrap();
+
+            // Find out if one of the device's BAR is being reprogrammed
+            let bar_reprog_params = device.detect_bar_reprogramming(register, data);
+
+            // Update the register value
+            device.write_config_register(register, offset, data);
+
+            // Reprogram the BAR if needed
+            if let Some(params) = bar_reprog_params {
+                pci_bus.device_reloc.move_bar(
+                    params.old_base,
+                    params.new_base,
+                    params.len,
+                    device.deref_mut(),
+                    params.region_type,
+                );
+            }
         }
     }
 }