arch: gic: Extend GicV3Its with its_device field

In current code, the ITS device fd of GICv3 will be lost after the
creation of GIC. This commit adds a new `its_device` field for the
`GicV3Its` struct, which will be useful to save the ITS device fd.
This fd will be used in restoring the ITS device.

Signed-off-by: Henry Wang <Henry.Wang@arm.com>

arch/src/aarch64/gic/gicv3.rs

@@ -1,5 +1,8 @@
+// Copyright 2021 Arm Limited (or its affiliates). All rights reserved.
 // Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
+//
+// This file implements the GicV3 device.
 
 pub mod kvm {
     use crate::aarch64::gic::dist_regs::{get_dist_regs, read_ctlr, set_dist_regs, write_ctlr};
@@ -50,7 +53,7 @@ pub mod kvm {
     type Result<T> = result::Result<T, Error>;
 
     pub struct KvmGicV3 {
-        /// The hypervisor agnostic device
+        /// The hypervisor agnostic device for the GicV3
         device: Arc<dyn hypervisor::Device>,
 
         /// Vector holding values of GICR_TYPER for each vCPU
@@ -168,6 +171,8 @@ pub mod kvm {
             self.vcpu_count
         }
 
+        fn set_its_device(&mut self, _its_device: Option<Arc<dyn hypervisor::Device>>) {}
+
         fn set_gicr_typers(&mut self, vcpu_states: &[CpuState]) {
             let gicr_typers = construct_gicr_typers(vcpu_states);
             self.gicr_typers = gicr_typers;
@@ -202,7 +207,7 @@ pub mod kvm {
 
         fn init_device_attributes(
             _vm: &Arc<dyn hypervisor::Vm>,
-            gic_device: &dyn GicDevice,
+            gic_device: &mut dyn GicDevice,
         ) -> crate::aarch64::gic::Result<()> {
             /* Setting up the distributor attribute.
              We are placing the GIC below 1GB so we need to substract the size of the distributor.

arch/src/aarch64/gic/gicv3_its.rs

@@ -1,5 +1,7 @@
-// Copyright 2020 ARM Limited
+// Copyright 2021 Arm Limited (or its affiliates). All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
+//
+// This file implements the GicV3 device with ITS (Virtual Interrupt Translation Service).
 
 pub mod kvm {
     use std::any::Any;
@@ -13,9 +15,12 @@ pub mod kvm {
     use hypervisor::CpuState;
 
     pub struct KvmGicV3Its {
-        /// The hypervisor agnostic device
+        /// The hypervisor agnostic device for the GicV3
         device: Arc<dyn hypervisor::Device>,
 
+        /// The hypervisor agnostic device for the Its device
+        its_device: Option<Arc<dyn hypervisor::Device>>,
+
         /// GIC device properties, to be used for setting up the fdt entry
         gic_properties: [u64; 4],
 
@@ -43,6 +48,10 @@ pub mod kvm {
             &self.device
         }
 
+        fn its_device(&self) -> Option<&Arc<dyn hypervisor::Device>> {
+            self.its_device.as_ref()
+        }
+
         fn fdt_compatibility(&self) -> &str {
             "arm,gic-v3"
         }
@@ -71,6 +80,10 @@ pub mod kvm {
             self.vcpu_count
         }
 
+        fn set_its_device(&mut self, its_device: Option<Arc<dyn hypervisor::Device>>) {
+            self.its_device = its_device;
+        }
+
         fn set_gicr_typers(&mut self, _vcpu_states: &[CpuState]) {}
 
         fn as_any_concrete_mut(&mut self) -> &mut dyn Any {
@@ -89,6 +102,7 @@ pub mod kvm {
         ) -> Box<dyn GicDevice> {
             Box::new(KvmGicV3Its {
                 device,
+                its_device: None,
                 gic_properties: [
                     KvmGicV3::get_dist_addr(),
                     KvmGicV3::get_dist_size(),
@@ -105,7 +119,7 @@ pub mod kvm {
 
         fn init_device_attributes(
             vm: &Arc<dyn hypervisor::Vm>,
-            gic_device: &dyn GicDevice,
+            gic_device: &mut dyn GicDevice,
         ) -> Result<()> {
             KvmGicV3::init_device_attributes(vm, gic_device)?;
 
@@ -135,6 +149,8 @@ pub mod kvm {
                 0,
             )?;
 
+            gic_device.set_its_device(Some(its_fd));
+
             Ok(())
         }
     }

arch/src/aarch64/gic/mod.rs

@@ -31,6 +31,11 @@ pub trait GicDevice: Send {
     /// Returns the hypervisor agnostic Device of the GIC device
     fn device(&self) -> &Arc<dyn hypervisor::Device>;
 
+    /// Returns the hypervisor agnostic Device of the ITS device
+    fn its_device(&self) -> Option<&Arc<dyn hypervisor::Device>> {
+        None
+    }
+
     /// Returns the fdt compatibility property of the device
     fn fdt_compatibility(&self) -> &str;
 
@@ -58,6 +63,8 @@ pub trait GicDevice: Send {
         &[]
     }
 
+    fn set_its_device(&mut self, its_device: Option<Arc<dyn hypervisor::Device>>);
+
     /// Get the values of GICR_TYPER for each vCPU.
     fn set_gicr_typers(&mut self, vcpu_states: &[CpuState]);
 
@@ -88,7 +95,7 @@ pub mod kvm {
         /// Setup the device-specific attributes
         fn init_device_attributes(
             vm: &Arc<dyn hypervisor::Vm>,
-            gic_device: &dyn GicDevice,
+            gic_device: &mut dyn GicDevice,
         ) -> Result<()>;
 
         /// Initialize a GIC device
@@ -179,9 +186,9 @@ pub mod kvm {
         fn new(vm: &Arc<dyn hypervisor::Vm>, vcpu_count: u64) -> Result<Box<dyn GicDevice>> {
             let vgic_fd = Self::init_device(vm)?;
 
-            let device = Self::create_device(vgic_fd, vcpu_count);
+            let mut device = Self::create_device(vgic_fd, vcpu_count);
 
-            Self::init_device_attributes(vm, &*device)?;
+            Self::init_device_attributes(vm, &mut *device)?;
 
             Self::finalize_device(&*device)?;