refactor: move CpuConfiguration creation into itself

Move manual creation of `CpuConfiguration` from
`configure_system_for_boot` into `CpuConfiguration::new`.

Signed-off-by: Egor Lazarchuk <[email protected]>

Author: ShadowCurse

src/vmm/src/arch/aarch64/mod.rs

@@ -27,8 +27,6 @@ use linux_loader::loader::{Cmdline, KernelLoader};
 use vm_memory::GuestMemoryError;
 
 use self::gic::GICDevice;
-use crate::arch::aarch64::regs::Aarch64RegisterVec;
-use crate::arch::aarch64::vcpu::{VcpuArchError, get_registers};
 use crate::arch::{BootProtocol, DeviceType, EntryPoint};
 use crate::cpu_config::aarch64::{CpuConfiguration, CpuConfigurationError};
 use crate::cpu_config::templates::CustomCpuTemplate;
@@ -51,12 +49,10 @@ pub enum ConfigurationError {
     KernelFile,
     /// Cannot load kernel due to invalid memory configuration or invalid kernel image: {0}
     KernelLoader(linux_loader::loader::Error),
-    /// Error initializing the vcpu: {0}
-    VcpuInit(KvmVcpuError),
+    /// Error creating vcpu configuration: {0}
+    VcpuConfig(CpuConfigurationError),
     /// Error configuring the vcpu: {0}
     VcpuConfigure(KvmVcpuError),
-    /// Error reading vcpu registers: {0}
-    VcpuGetRegs(VcpuArchError),
     /// Error applying vcpu template: {0}
     VcpuApplyTemplate(CpuConfigurationError),
 }
@@ -84,18 +80,8 @@ pub fn configure_system_for_boot(
     boot_cmdline: Cmdline,
 ) -> Result<(), ConfigurationError> {
     // Construct the base CpuConfiguration to apply CPU template onto.
-    let cpu_config = {
-        for vcpu in vcpus.iter_mut() {
-            vcpu.kvm_vcpu
-                .init(&cpu_template.vcpu_features)
-                .map_err(ConfigurationError::VcpuInit)?;
-        }
-
-        let mut regs = Aarch64RegisterVec::default();
-        get_registers(&vcpus[0].kvm_vcpu.fd, &cpu_template.reg_list(), &mut regs)
-            .map_err(ConfigurationError::VcpuGetRegs)?;
-        CpuConfiguration { regs }
-    };
+    let cpu_config =
+        CpuConfiguration::new(cpu_template, vcpus).map_err(ConfigurationError::VcpuConfig)?;
 
     // Apply CPU template to the base CpuConfiguration.
     let cpu_config = CpuConfiguration::apply_template(cpu_config, cpu_template)

src/vmm/src/arch/x86_64/mod.rs

@@ -48,7 +48,7 @@ use super::EntryPoint;
 use crate::acpi::create_acpi_tables;
 use crate::arch::{BootProtocol, SYSTEM_MEM_SIZE, SYSTEM_MEM_START};
 use crate::cpu_config::templates::{CustomCpuTemplate, GuestConfigError};
-use crate::cpu_config::x86_64::{CpuConfiguration, cpuid};
+use crate::cpu_config::x86_64::CpuConfiguration;
 use crate::device_manager::resources::ResourceAllocator;
 use crate::initrd::InitrdConfig;
 use crate::utils::{mib_to_bytes, u64_to_usize};
@@ -153,16 +153,8 @@ pub fn configure_system_for_boot(
     boot_cmdline: Cmdline,
 ) -> Result<(), ConfigurationError> {
     // Construct the base CpuConfiguration to apply CPU template onto.
-    let cpu_config = {
-        let cpuid = cpuid::Cpuid::try_from(vmm.kvm.supported_cpuid.clone())
-            .map_err(GuestConfigError::CpuidFromKvmCpuid)?;
-        let msrs = vcpus[0]
-            .kvm_vcpu
-            .get_msrs(cpu_template.msr_index_iter())
-            .map_err(GuestConfigError::VcpuIoctl)?;
-        CpuConfiguration { cpuid, msrs }
-    };
-
+    let cpu_config =
+        CpuConfiguration::new(vmm.kvm.supported_cpuid.clone(), cpu_template, &vcpus[0])?;
     // Apply CPU template to the base CpuConfiguration.
     let cpu_config = CpuConfiguration::apply_template(cpu_config, cpu_template)?;
 

src/vmm/src/cpu_config/aarch64/mod.rs

@@ -9,13 +9,19 @@ pub mod static_cpu_templates;
 pub mod test_utils;
 
 use super::templates::CustomCpuTemplate;
+use crate::Vcpu;
 use crate::arch::aarch64::regs::{Aarch64RegisterVec, RegSize};
-use crate::arch::aarch64::vcpu::VcpuArchError;
+use crate::arch::aarch64::vcpu::{VcpuArchError, get_registers};
+use crate::vstate::vcpu::KvmVcpuError;
 
 /// Errors thrown while configuring templates.
-#[derive(Debug, PartialEq, Eq, thiserror::Error)]
-#[error("Failed to create a guest cpu configuration: {0}")]
-pub struct CpuConfigurationError(#[from] pub VcpuArchError);
+#[derive(Debug, PartialEq, Eq, thiserror::Error, displaydoc::Display)]
+pub enum CpuConfigurationError {
+    /// Error initializing the vcpu: {0}
+    VcpuInit(KvmVcpuError),
+    /// Error reading vcpu registers: {0}
+    VcpuGetRegs(VcpuArchError),
+}
 
 /// CPU configuration for aarch64
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
@@ -25,6 +31,23 @@ pub struct CpuConfiguration {
 }
 
 impl CpuConfiguration {
+    /// Create new CpuConfiguration.
+    pub fn new(
+        cpu_template: &CustomCpuTemplate,
+        vcpus: &mut [Vcpu],
+    ) -> Result<Self, CpuConfigurationError> {
+        for vcpu in vcpus.iter_mut() {
+            vcpu.kvm_vcpu
+                .init(&cpu_template.vcpu_features)
+                .map_err(CpuConfigurationError::VcpuInit)?;
+        }
+
+        let mut regs = Aarch64RegisterVec::default();
+        get_registers(&vcpus[0].kvm_vcpu.fd, &cpu_template.reg_list(), &mut regs)
+            .map_err(CpuConfigurationError::VcpuGetRegs)?;
+        Ok(CpuConfiguration { regs })
+    }
+
     /// Creates new guest CPU config based on the provided template
     pub fn apply_template(
         mut self,

src/vmm/src/cpu_config/x86_64/mod.rs

@@ -12,8 +12,11 @@ pub mod test_utils;
 
 use std::collections::BTreeMap;
 
+use kvm_bindings::CpuId;
+
 use self::custom_cpu_template::CpuidRegister;
 use super::templates::CustomCpuTemplate;
+use crate::Vcpu;
 use crate::cpu_config::x86_64::cpuid::{Cpuid, CpuidKey};
 
 /// Errors thrown while configuring templates.
@@ -41,6 +44,21 @@ pub struct CpuConfiguration {
 }
 
 impl CpuConfiguration {
+    /// Create new CpuConfiguration.
+    pub fn new(
+        supported_cpuid: CpuId,
+        cpu_template: &CustomCpuTemplate,
+        first_vcpu: &Vcpu,
+    ) -> Result<Self, CpuConfigurationError> {
+        let cpuid = cpuid::Cpuid::try_from(supported_cpuid)
+            .map_err(CpuConfigurationError::CpuidFromKvmCpuid)?;
+        let msrs = first_vcpu
+            .kvm_vcpu
+            .get_msrs(cpu_template.msr_index_iter())
+            .map_err(CpuConfigurationError::VcpuIoctl)?;
+        Ok(CpuConfiguration { cpuid, msrs })
+    }
+
     /// Modifies provided config with changes from template
     pub fn apply_template(
         self,