fix(cpu-template-helper): ignore wide registers

When SVE extension is enabled on aarch64 cpus, KVM will
return wide registers when queried. Because cpu templates
do not support registers wider than 128 bits we need
to ignore wide registers when converting cpu configuration
into a cpu template.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

src/cpu-template-helper/src/template/dump/aarch64.rs

@@ -4,24 +4,26 @@
 use vmm::arch::aarch64::regs::RegSize;
 use vmm::cpu_config::aarch64::custom_cpu_template::RegisterModifier;
 use vmm::cpu_config::templates::{CpuConfiguration, CustomCpuTemplate, RegisterValueFilter};
+use vmm::logger::warn;
 
 use crate::utils::aarch64::reg_modifier;
 
 pub fn config_to_template(cpu_config: &CpuConfiguration) -> CustomCpuTemplate {
     let mut reg_modifiers: Vec<RegisterModifier> = cpu_config
         .regs
         .iter()
-        .map(|reg| match reg.size() {
-            RegSize::U32 => {
-                reg_modifier!(reg.id, u128::from(reg.value::<u32, 4>()))
+        .filter_map(|reg| match reg.size() {
+            RegSize::U32 => Some(reg_modifier!(reg.id, u128::from(reg.value::<u32, 4>()))),
+            RegSize::U64 => Some(reg_modifier!(reg.id, u128::from(reg.value::<u64, 8>()))),
+            RegSize::U128 => Some(reg_modifier!(reg.id, reg.value::<u128, 16>())),
+            _ => {
+                warn!(
+                    "Only 32, 64 and 128 bit wide registers are supported in cpu templates. \
+                     Skipping: {:#x}",
+                    reg.id
+                );
+                None
             }
-            RegSize::U64 => {
-                reg_modifier!(reg.id, u128::from(reg.value::<u64, 8>()))
-            }
-            RegSize::U128 => {
-                reg_modifier!(reg.id, reg.value::<u128, 16>())
-            }
-            _ => unreachable!("Only 32, 64 and 128 bit wide registers are supported"),
         })
         .collect();
     reg_modifiers.sort_by_key(|modifier| modifier.addr);
@@ -43,6 +45,10 @@ mod tests {
     const KVM_REG_SIZE_U32: u64 = 0x0020000000000000;
     const KVM_REG_SIZE_U64: u64 = 0x0030000000000000;
     const KVM_REG_SIZE_U128: u64 = 0x0040000000000000;
+    const KVM_REG_SIZE_U256: u64 = 0x0050000000000000;
+    const KVM_REG_SIZE_U512: u64 = 0x0060000000000000;
+    const KVM_REG_SIZE_U1024: u64 = 0x0070000000000000;
+    const KVM_REG_SIZE_U2048: u64 = 0x0080000000000000;
 
     fn build_sample_regs() -> Aarch64RegisterVec {
         let mut v = Aarch64RegisterVec::default();
@@ -58,6 +64,10 @@ mod tests {
             KVM_REG_SIZE_U64,
             &0x0000_ffff_0000_ffff_u64.to_le_bytes(),
         ));
+        v.push(Aarch64RegisterRef::new(KVM_REG_SIZE_U256, &[0x69; 32]));
+        v.push(Aarch64RegisterRef::new(KVM_REG_SIZE_U512, &[0x69; 64]));
+        v.push(Aarch64RegisterRef::new(KVM_REG_SIZE_U1024, &[0x69; 128]));
+        v.push(Aarch64RegisterRef::new(KVM_REG_SIZE_U2048, &[0x69; 256]));
         v
     }
 

tests/integration_tests/functional/test_cpu_template_helper.py

@@ -410,8 +410,6 @@ def test_json_static_templates(
     """
     Verify that JSON static CPU templates are applied as intended.
     """
-    if custom_cpu_template["name"] == "aarch64_with_sve_and_pac":
-        pytest.skip("does not work yet")
     # Generate VM config with JSON static CPU template
     microvm = test_microvm_with_api
     microvm.spawn()