kernel: Bypass reading non-existent msrs on non-intel machines

kernel/src/lib.rs

@@ -197,8 +197,16 @@ fn start_init_thread() {
 
 #[no_mangle]
 pub extern "C" fn rust_main() -> ! {
+    let mut isIntel : bool = false;
+
     match CpuId::new().get_vendor_info() {
-        Some(vendor) => println!("RedLeaf booting (CPU model: {})", vendor.as_string()),
+        Some(vendor) => {
+            let vendor_string = vendor.as_string();
+            println!("RedLeaf booting (CPU model: {})", vendor_string);
+            if vendor_string == "GenuineIntel" {
+                isIntel = true;
+            }
+        },
         None => println!("RedLeaf booting on (CPU model: unknown)"),
     }
 
@@ -235,7 +243,7 @@ pub extern "C" fn rust_main() -> ! {
     // To enable NX mappings
     unsafe {
         // Enable NXE bit (11)
-        use x86::msr::{rdmsr, wrmsr, IA32_EFER};
+        use x86::msr::{rdmsr, wrmsr, IA32_EFER, IA32_MISC_ENABLE, MSR_PLATFORM_INFO, IA32_PERF_STATUS, IA32_PERF_CTL, IA32_MPERF, IA32_APERF};
         let efer = rdmsr(IA32_EFER) | 1 << 11;
         wrmsr(IA32_EFER, efer);
 
@@ -244,37 +252,39 @@ pub extern "C" fn rust_main() -> ! {
             let aperf_old = rdmsr(IA32_APERF);
             let mperf_old = rdmsr(IA32_MPERF);
 
-            let perf_status = rdmsr(IA32_PERF_STATUS);
-            let perf_ctl = rdmsr(IA32_PERF_CTL);
-            println!(
-                "IA32_PERF_STATUS {:x} IA32_PERF_CTL {:x}",
-                perf_status, perf_ctl
-            );
-
-            // request 2.2GHz
-            // If you want to request a different frequency, write to PERF_CTL
-            //wrmsr(IA32_PERF_CTL, 0x1600);
-
-            let mut misc = rdmsr(IA32_MISC_ENABLE);
-            // Disable turbo boost
-            misc |= (1u64 << 38);
-            // Disable Intel speed-step technology
-            misc &= !(1u64 << 16);
-            wrmsr(IA32_MISC_ENABLE, misc);
-            println!("IA32_MISC_ENABLE {:x}", rdmsr(IA32_MISC_ENABLE));
-
-            // Read MSR_PLATFORM_INFO
-            let plat_info = rdmsr(MSR_PLATFORM_INFO);
-            println!("MSR_PLATFORM_INFO {:x}", plat_info);
-            let nominal_tsc = (plat_info >> 8) & 0xff;
-            let lfm = (plat_info >> 40) & 0xf;
-
-            // FIXME: 100MHz multiplier differs with family. For c220g2/Haswell, it is 100.
-            println!(
-                "Nominal TSC frequency {} MHz LFM {} MHz",
-                nominal_tsc * 100,
-                lfm * 100
-            );
+            if isIntel {
+                let perf_status = rdmsr(IA32_PERF_STATUS);
+                let perf_ctl = rdmsr(IA32_PERF_CTL);
+                println!(
+                    "IA32_PERF_STATUS {:x} IA32_PERF_CTL {:x}",
+                    perf_status, perf_ctl
+                );
+
+                // request 2.2GHz
+                // If you want to request a different frequency, write to PERF_CTL
+                //wrmsr(IA32_PERF_CTL, 0x1600);
+
+                let mut misc = rdmsr(IA32_MISC_ENABLE);
+                // Disable turbo boost
+                misc |= (1u64 << 38);
+                // Disable Intel speed-step technology
+                misc &= !(1u64 << 16);
+                wrmsr(IA32_MISC_ENABLE, misc);
+                println!("IA32_MISC_ENABLE {:x}", rdmsr(IA32_MISC_ENABLE));
+
+                // Read MSR_PLATFORM_INFO
+                let plat_info = rdmsr(MSR_PLATFORM_INFO);
+                println!("MSR_PLATFORM_INFO {:x}", plat_info);
+                let nominal_tsc = (plat_info >> 8) & 0xff;
+                let lfm = (plat_info >> 40) & 0xf;
+
+                // FIXME: 100MHz multiplier differs with family. For c220g2/Haswell, it is 100.
+                println!(
+                    "Nominal TSC frequency {} MHz LFM {} MHz",
+                    nominal_tsc * 100,
+                    lfm * 100
+                );
+            }
 
             let aperf_delta = rdmsr(IA32_APERF) - aperf_old;
             let mperf_delta = rdmsr(IA32_MPERF) - mperf_old;