hypervisor: Add support for setting KVM identity map

Extending the Vm trait with set_identity_map_address() in order to
expose this ioctl to the VMM.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
(cherry picked from commit c452471c4e)
Signed-off-by: Rob Bradford <robert.bradford@intel.com>

hypervisor/src/kvm/mod.rs

@@ -135,6 +135,15 @@ pub struct KvmVm {
 /// vm.set/get().unwrap()
 ///
 impl vm::Vm for KvmVm {
+    #[cfg(target_arch = "x86_64")]
+    ///
+    /// Sets the address of the one-page region in the VM's address space.
+    ///
+    fn set_identity_map_address(&self, address: u64) -> vm::Result<()> {
+        self.fd
+            .set_identity_map_address(address)
+            .map_err(|e| vm::HypervisorVmError::SetIdentityMapAddress(e.into()))
+    }
     #[cfg(target_arch = "x86_64")]
     ///
     /// Sets the address of the three-page region in the VM's address space.

hypervisor/src/kvm/x86_64/mod.rs

@@ -124,6 +124,9 @@ pub fn check_required_kvm_extensions(kvm: &Kvm) -> KvmResult<()> {
     if !kvm.check_extension(Cap::SplitIrqchip) {
         return Err(KvmError::CapabilityMissing(Cap::SplitIrqchip));
     }
+    if !kvm.check_extension(Cap::SetIdentityMapAddr) {
+        return Err(KvmError::CapabilityMissing(Cap::SetIdentityMapAddr));
+    }
     if !kvm.check_extension(Cap::SetTssAddr) {
         return Err(KvmError::CapabilityMissing(Cap::SetTssAddr));
     }

hypervisor/src/mshv/mod.rs

@@ -764,6 +764,13 @@ fn hv_state_init() -> Arc<RwLock<HvState>> {
 /// vm.set/get().unwrap()
 ///
 impl vm::Vm for MshvVm {
+    #[cfg(target_arch = "x86_64")]
+    ///
+    /// Sets the address of the one-page region in the VM's address space.
+    ///
+    fn set_identity_map_address(&self, _address: u64) -> vm::Result<()> {
+        Ok(())
+    }
     #[cfg(target_arch = "x86_64")]
     ///
     /// Sets the address of the three-page region in the VM's address space.

hypervisor/src/vm.rs

@@ -58,6 +58,11 @@ pub enum HypervisorVmError {
     #[error("Failed to create Vcpu: {0}")]
     CreateVcpu(#[source] anyhow::Error),
     ///
+    /// Identity map address error
+    ///
+    #[error("Failed to set identity map address: {0}")]
+    SetIdentityMapAddress(#[source] anyhow::Error),
+    ///
     /// TSS address error
     ///
     #[error("Failed to set TSS address: {0}")]
@@ -217,6 +222,9 @@ pub type Result<T> = std::result::Result<T, HypervisorVmError>;
 /// This crate provides a hypervisor-agnostic interfaces for Vm
 ///
 pub trait Vm: Send + Sync {
+    #[cfg(target_arch = "x86_64")]
+    /// Sets the address of the one-page region in the VM's address space.
+    fn set_identity_map_address(&self, address: u64) -> Result<()>;
     #[cfg(target_arch = "x86_64")]
     /// Sets the address of the three-page region in the VM's address space.
     fn set_tss_address(&self, offset: usize) -> Result<()>;