arch: AArch64: implement save/restore for GICv3

This commit implements the save/restore for GICv3.

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

arch/Cargo.toml

@@ -13,7 +13,11 @@ byteorder = "1.3.4"
 hypervisor = { path = "../hypervisor" }
 libc = "0.2.77"
 log = "0.4.11"
+serde = {version = ">=1.0.27", features = ["rc"] }
+serde_derive = ">=1.0.27"
+serde_json = ">=1.0.9"
 vm-memory = { version = "0.2.1", features = ["backend-mmap"] }
+vm-migration = { path = "../vm-migration" }
 acpi_tables = { path = "../acpi_tables", optional = true }
 arch_gen = { path = "../arch_gen" }
 

arch/src/aarch64/gic/gicv3.rs

@@ -2,13 +2,45 @@
 // SPDX-License-Identifier: Apache-2.0
 
 pub mod kvm {
-    use crate::aarch64::gic::kvm::KvmGICDevice;
+    use crate::aarch64::gic::dist_regs::{get_dist_regs, read_ctlr, set_dist_regs, write_ctlr};
-    use crate::aarch64::gic::{Error, GICDevice};
+    use crate::aarch64::gic::icc_regs::{get_icc_regs, set_icc_regs};
+    use crate::aarch64::gic::kvm::{save_pending_tables, KvmGICDevice};
+    use crate::aarch64::gic::redist_regs::{get_redist_regs, set_redist_regs};
+    use crate::aarch64::gic::GICDevice;
     use crate::layout;
+    use anyhow::anyhow;
     use hypervisor::kvm::kvm_bindings;
     use std::convert::TryInto;
     use std::sync::Arc;
     use std::{boxed::Box, result};
+    use vm_migration::{
+        Migratable, MigratableError, Pausable, Snapshot, SnapshotDataSection, Snapshottable,
+        Transportable,
+    };
+
+    /// Errors thrown while saving/restoring the GICv3.
+    #[derive(Debug)]
+    pub enum Error {
+        /// Error in saving RDIST pending tables into guest RAM.
+        SavePendingTables(crate::aarch64::gic::Error),
+        /// Error in saving GIC distributor registers.
+        SaveDistributorRegisters(crate::aarch64::gic::Error),
+        /// Error in restoring GIC distributor registers.
+        RestoreDistributorRegisters(crate::aarch64::gic::Error),
+        /// Error in saving GIC distributor control registers.
+        SaveDistributorCtrlRegisters(crate::aarch64::gic::Error),
+        /// Error in restoring GIC distributor control registers.
+        RestoreDistributorCtrlRegisters(crate::aarch64::gic::Error),
+        /// Error in saving GIC redistributor registers.
+        SaveRedistributorRegisters(crate::aarch64::gic::Error),
+        /// Error in restoring GIC redistributor registers.
+        RestoreRedistributorRegisters(crate::aarch64::gic::Error),
+        /// Error in saving GIC CPU interface registers.
+        SaveICCRegisters(crate::aarch64::gic::Error),
+        /// Error in restoring GIC CPU interface registers.
+        RestoreICCRegisters(crate::aarch64::gic::Error),
+    }
+
     type Result<T> = result::Result<T, Error>;
 
     pub struct KvmGICv3 {
@@ -25,6 +57,15 @@ pub mod kvm {
         vcpu_count: u64,
     }
 
+    #[derive(Serialize, Deserialize)]
+    pub struct Gicv3State {
+        dist: Vec<u32>,
+        rdist: Vec<u32>,
+        icc: Vec<u32>,
+        // special register that enables interrupts and affinity routing
+        gicd_ctlr: u32,
+    }
+
     impl KvmGICv3 {
         // Unfortunately bindgen omits defines that are based on other defines.
         // See arch/arm64/include/uapi/asm/kvm.h file from the linux kernel.
@@ -54,6 +95,48 @@ pub mod kvm {
         pub fn get_redists_size(vcpu_count: u64) -> u64 {
             vcpu_count * KvmGICv3::KVM_VGIC_V3_REDIST_SIZE
         }
+
+        /// Save the state of GIC.
+        fn state(&self, gicr_typers: &[u64]) -> Result<Gicv3State> {
+            // Flush redistributors pending tables to guest RAM.
+            save_pending_tables(&self.device()).map_err(Error::SavePendingTables)?;
+
+            let gicd_ctlr =
+                read_ctlr(&self.device()).map_err(Error::SaveDistributorCtrlRegisters)?;
+
+            let dist_state =
+                get_dist_regs(&self.device()).map_err(Error::SaveDistributorRegisters)?;
+
+            let rdist_state = get_redist_regs(&self.device(), &gicr_typers)
+                .map_err(Error::SaveRedistributorRegisters)?;
+
+            let icc_state =
+                get_icc_regs(&self.device(), &gicr_typers).map_err(Error::SaveICCRegisters)?;
+
+            Ok(Gicv3State {
+                dist: dist_state,
+                rdist: rdist_state,
+                icc: icc_state,
+                gicd_ctlr,
+            })
+        }
+
+        /// Restore the state of GIC.
+        fn set_state(&mut self, gicr_typers: &[u64], state: &Gicv3State) -> Result<()> {
+            write_ctlr(&self.device(), state.gicd_ctlr)
+                .map_err(Error::RestoreDistributorCtrlRegisters)?;
+
+            set_dist_regs(&self.device(), &state.dist)
+                .map_err(Error::RestoreDistributorRegisters)?;
+
+            set_redist_regs(&self.device(), gicr_typers, &state.rdist)
+                .map_err(Error::RestoreRedistributorRegisters)?;
+
+            set_icc_regs(&self.device(), &gicr_typers, &state.icc)
+                .map_err(Error::RestoreICCRegisters)?;
+
+            Ok(())
+        }
     }
 
     impl GICDevice for KvmGICv3 {
@@ -107,7 +190,7 @@ pub mod kvm {
         fn init_device_attributes(
             _vm: &Arc<dyn hypervisor::Vm>,
             gic_device: &dyn GICDevice,
-        ) -> Result<()> {
+        ) -> 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.
             */
@@ -133,4 +216,55 @@ pub mod kvm {
             Ok(())
         }
     }
+
+    const GIC_V3_SNAPSHOT_ID: &str = "gic-v3";
+    impl Snapshottable for KvmGICv3 {
+        fn id(&self) -> String {
+            GIC_V3_SNAPSHOT_ID.to_string()
+        }
+
+        fn snapshot(&mut self) -> std::result::Result<Snapshot, MigratableError> {
+            let gicr_typers = self.gicr_typers.clone();
+            let snapshot = serde_json::to_vec(&self.state(&gicr_typers).unwrap())
+                .map_err(|e| MigratableError::Snapshot(e.into()))?;
+
+            let mut gic_v3_snapshot = Snapshot::new(self.id().as_str());
+            gic_v3_snapshot.add_data_section(SnapshotDataSection {
+                id: format!("{}-section", self.id()),
+                snapshot,
+            });
+
+            Ok(gic_v3_snapshot)
+        }
+
+        fn restore(&mut self, snapshot: Snapshot) -> std::result::Result<(), MigratableError> {
+            if let Some(gic_v3_section) = snapshot
+                .snapshot_data
+                .get(&format!("{}-section", self.id()))
+            {
+                let gic_v3_state = match serde_json::from_slice(&gic_v3_section.snapshot) {
+                    Ok(state) => state,
+                    Err(error) => {
+                        return Err(MigratableError::Restore(anyhow!(
+                            "Could not deserialize GICv3 {}",
+                            error
+                        )))
+                    }
+                };
+
+                let gicr_typers = self.gicr_typers.clone();
+                return self.set_state(&gicr_typers, &gic_v3_state).map_err(|e| {
+                    MigratableError::Restore(anyhow!("Could not restore GICv3 state {:?}", e))
+                });
+            }
+
+            Err(MigratableError::Restore(anyhow!(
+                "Could not find GICv3 snapshot section"
+            )))
+        }
+    }
+
+    impl Pausable for KvmGICv3 {}
+    impl Transportable for KvmGICv3 {}
+    impl Migratable for KvmGICv3 {}
 }

arch/src/lib.rs

@@ -14,6 +14,7 @@
     clippy::cast_ptr_alignment
 )]
 
+extern crate anyhow;
 extern crate byteorder;
 extern crate hypervisor;
 extern crate libc;
@@ -23,7 +24,13 @@ extern crate log;
 extern crate acpi_tables;
 extern crate arch_gen;
 extern crate linux_loader;
+extern crate serde;
 extern crate vm_memory;
+extern crate vm_migration;
+#[cfg(target_arch = "aarch64")]
+#[macro_use]
+extern crate serde_derive;
+extern crate serde_json;
 
 use std::fmt;
 use std::result;