CPUID VMExit handler

2025-08-10 13:59:54 +00:00
parent ab26b4bf45
commit 0f0aeda267
3 changed files with 306 additions and 1 deletions
--- a/nel_os_kernel/src/vmm/x86_64/intel/cpuid.rs
+++ b/nel_os_kernel/src/vmm/x86_64/intel/cpuid.rs
@ -0,0 +1,288 @@
+use modular_bitfield::bitfield;
+use raw_cpuid::cpuid;
+
+use crate::vmm::x86_64::intel::vcpu::IntelVCpu;
+
+pub fn handle_cpuid_vmexit(vcpu: &mut IntelVCpu) {
+    let regs = &mut vcpu.guest_registers;
+
+    let vendor: &[u8; 12] = b"miHypervisor";
+    let brand_string: &[u8; 48] = b"mii Hypervisor CPU on Intel VT-x               \0";
+    let vendor = unsafe { core::mem::transmute::<&[u8; 12], &[u32; 3]>(vendor) };
+    let brand_string = unsafe { core::mem::transmute::<&[u8; 48], &[u32; 12]>(brand_string) };
+
+    match VmxLeaf::from(regs.rax) {
+        VmxLeaf::EXTENDED_FEATURE_2 => {
+            regs.rax = brand_string[0] as u64;
+            regs.rbx = brand_string[1] as u64;
+            regs.rcx = brand_string[2] as u64;
+            regs.rdx = brand_string[3] as u64;
+        }
+        VmxLeaf::EXTENDED_FEATURE_3 => {
+            regs.rax = brand_string[4] as u64;
+            regs.rbx = brand_string[5] as u64;
+            regs.rcx = brand_string[6] as u64;
+            regs.rdx = brand_string[7] as u64;
+        }
+        VmxLeaf::EXTENDED_FEATURE_4 => {
+            regs.rax = brand_string[8] as u64;
+            regs.rbx = brand_string[9] as u64;
+            regs.rcx = brand_string[10] as u64;
+            regs.rdx = brand_string[11] as u64;
+        }
+        VmxLeaf::EXTENDED_ENUMERATION => match regs.rcx {
+            0 => {
+                regs.rax = 0b11;
+                regs.rbx = 576;
+                regs.rcx = 576;
+                regs.rdx = 0x00000000;
+            }
+            1 => {
+                regs.rax = 0x00000001;
+                regs.rbx = 0;
+                regs.rcx = 0;
+                regs.rdx = 0;
+            }
+            2 => {
+                regs.rax = 512;
+                regs.rbx = 0;
+                regs.rcx = 0;
+                regs.rdx = 0;
+            }
+            _ => {
+                invalid(vcpu);
+            }
+        },
+        VmxLeaf::EXTENDED_FEATURE => match regs.rcx {
+            0 => {
+                let mut ebx = ExtFeatureEbx0::new()
+                    .with_fsgsbase(false)
+                    .with_smep(true)
+                    .with_invpcid(false)
+                    .with_smap(true);
+                regs.rax = 1;
+                regs.rbx = u32::from(ebx) as u64;
+                regs.rcx = 0;
+                regs.rdx = 0;
+            }
+            1 => {
+                invalid(vcpu);
+            }
+            2 => {
+                invalid(vcpu);
+            }
+            _ => {
+                panic!("Unhandled CPUID leaf: {:#x}.{:#x}", regs.rax, regs.rcx);
+            }
+        },
+        VmxLeaf::EXTENDED_PROCESSOR_SIGNATURE => {
+            let signature = cpuid!(0x80000001, 0);
+            regs.rax = 0x00000000;
+            regs.rbx = 0x00000000;
+            regs.rcx = signature.ecx as u64;
+            regs.rdx = signature.edx as u64;
+        }
+        VmxLeaf::EXTENDED_FUNCTION => {
+            regs.rax = 0x80000000 + 4;
+            regs.rbx = 0x00000000;
+            regs.rcx = 0x00000000;
+            regs.rdx = 0x00000000;
+        }
+        VmxLeaf::MAXIMUM_INPUT => {
+            regs.rax = 0x20;
+            regs.rbx = vendor[0] as u64;
+            regs.rcx = vendor[2] as u64;
+            regs.rdx = vendor[1] as u64;
+        }
+        VmxLeaf::VERSION_AND_FEATURE_INFO => {
+            let ecx = FeatureInfoEcx::new()
+                .with_pcid(true)
+                .with_sse4_1(true)
+                .with_sse4_2(true)
+                .with_xsave(true)
+                .with_osxsave(true);
+
+            let edx = FeatureInfoEdx::new()
+                .with_fpu(true)
+                .with_vme(true)
+                .with_de(true)
+                .with_pse(true)
+                .with_msr(true)
+                .with_pae(true)
+                .with_cx8(true)
+                .with_sep(true)
+                .with_pge(true)
+                .with_cmov(true)
+                .with_pse36(true)
+                .with_acpi(true)
+                .with_fxsr(true)
+                .with_sse(true)
+                .with_sse2(true);
+
+            let mut version_and_feature_info = cpuid!(0x1, 0);
+            let feature = cpuid!(0x0, 0);
+            version_and_feature_info.ecx &= !(1 << 17);
+
+            regs.rax = version_and_feature_info.eax as u64;
+            regs.rbx = version_and_feature_info.ebx as u64;
+            regs.rcx = u32::from(ecx) as u64;
+            regs.rdx = u32::from(edx) as u64;
+        }
+        _ => {
+            invalid(vcpu);
+        }
+    }
+}
+
+fn invalid(vcpu: &mut IntelVCpu) {
+    let regs = &mut vcpu.guest_registers;
+
+    regs.rax = 0;
+    regs.rbx = 0;
+    regs.rcx = 0;
+    regs.rdx = 0;
+}
+
+#[bitfield]
+#[repr(u32)]
+#[derive(Debug, Clone, Copy)]
+pub struct FeatureInfoEcx {
+    pub sse3: bool,
+    pub pclmulqdq: bool,
+    pub dtes64: bool,
+    pub monitor: bool,
+    pub ds_cpl: bool,
+    pub vmx: bool,
+    pub smx: bool,
+    pub eist: bool,
+    pub tm2: bool,
+    pub ssse3: bool,
+    pub cnxt_id: bool,
+    pub sdbg: bool,
+    pub fma: bool,
+    pub cmpxchg16b: bool,
+    pub xtpr: bool,
+    pub pdcm: bool,
+    pub _reserved_0: bool,
+    pub pcid: bool,
+    pub dca: bool,
+    pub sse4_1: bool,
+    pub sse4_2: bool,
+    pub x2apic: bool,
+    pub movbe: bool,
+    pub popcnt: bool,
+    pub tsc_deadline: bool,
+    pub aesni: bool,
+    pub xsave: bool,
+    pub osxsave: bool,
+    pub avx: bool,
+    pub f16c: bool,
+    pub rdrand: bool,
+    pub hypervisor: bool,
+}
+
+#[bitfield]
+#[repr(u32)]
+#[derive(Debug, Clone, Copy)]
+pub struct FeatureInfoEdx {
+    pub fpu: bool,
+    pub vme: bool,
+    pub de: bool,
+    pub pse: bool,
+    pub tsc: bool,
+    pub msr: bool,
+    pub pae: bool,
+    pub mce: bool,
+    pub cx8: bool,
+    pub apic: bool,
+    pub _reserved_0: bool,
+    pub sep: bool,
+    pub mtrr: bool,
+    pub pge: bool,
+    pub mca: bool,
+    pub cmov: bool,
+    pub pat: bool,
+    pub pse36: bool,
+    pub psn: bool,
+    pub clfsh: bool,
+    pub _reserved_1: bool,
+    pub ds: bool,
+    pub acpi: bool,
+    pub mmx: bool,
+    pub fxsr: bool,
+    pub sse: bool,
+    pub sse2: bool,
+    pub ss: bool,
+    pub htt: bool,
+    pub tm: bool,
+    pub _reserved_2: bool,
+    pub pbe: bool,
+}
+
+#[bitfield]
+#[repr(u32)]
+#[derive(Debug, Clone, Copy)]
+pub struct ExtFeatureEbx0 {
+    pub fsgsbase: bool,
+    pub tsc_adjust: bool,
+    pub sgx: bool,
+    pub bmi1: bool,
+    pub hle: bool,
+    pub avx2: bool,
+    pub fdp: bool,
+    pub smep: bool,
+    pub bmi2: bool,
+    pub erms: bool,
+    pub invpcid: bool,
+    pub rtm: bool,
+    pub rdtm: bool,
+    pub fpucsds: bool,
+    pub mpx: bool,
+    pub rdta: bool,
+    pub avx512f: bool,
+    pub avx512dq: bool,
+    pub rdseed: bool,
+    pub adx: bool,
+    pub smap: bool,
+    pub avx512ifma: bool,
+    pub _reserved1: bool,
+    pub clflushopt: bool,
+    pub clwb: bool,
+    pub pt: bool,
+    pub avx512pf: bool,
+    pub avx512er: bool,
+    pub avx512cd: bool,
+    pub sha: bool,
+    pub avx512bw: bool,
+    pub avx512vl: bool,
+}
+
+pub enum VmxLeaf {
+    MAXIMUM_INPUT = 0x0,
+    VERSION_AND_FEATURE_INFO = 0x1,
+    EXTENDED_FEATURE = 0x7,
+    EXTENDED_ENUMERATION = 0xD,
+    EXTENDED_FUNCTION = 0x80000000,
+    EXTENDED_PROCESSOR_SIGNATURE = 0x80000001,
+    EXTENDED_FEATURE_2 = 0x80000002,
+    EXTENDED_FEATURE_3 = 0x80000003,
+    EXTENDED_FEATURE_4 = 0x80000004,
+    UNKNOWN = 0xFFFFFFFF,
+}
+
+impl VmxLeaf {
+    pub fn from(rax: u64) -> VmxLeaf {
+        match rax {
+            0x0 => VmxLeaf::MAXIMUM_INPUT,
+            0x1 => VmxLeaf::VERSION_AND_FEATURE_INFO,
+            0x7 => VmxLeaf::EXTENDED_FEATURE,
+            0xD => VmxLeaf::EXTENDED_ENUMERATION,
+            0x80000000 => VmxLeaf::EXTENDED_FUNCTION,
+            0x80000001 => VmxLeaf::EXTENDED_PROCESSOR_SIGNATURE,
+            0x80000002 => VmxLeaf::EXTENDED_FEATURE_2,
+            0x80000003 => VmxLeaf::EXTENDED_FEATURE_3,
+            0x80000004 => VmxLeaf::EXTENDED_FEATURE_4,
+            _ => VmxLeaf::UNKNOWN,
+        }
+    }
+}
--- a/nel_os_kernel/src/vmm/x86_64/intel/mod.rs
+++ b/nel_os_kernel/src/vmm/x86_64/intel/mod.rs
@ -1,5 +1,6 @@
 pub mod asm;
 mod controls;
+mod cpuid;
 mod ept;
 mod register;
 pub mod vcpu;
--- a/nel_os_kernel/src/vmm/x86_64/intel/vcpu.rs
+++ b/nel_os_kernel/src/vmm/x86_64/intel/vcpu.rs
@ -12,7 +12,7 @@ use crate::{
        x86_64::{
            common::{self, read_msr},
            intel::{
-                controls, ept,
+                controls, cpuid, ept,
                register::GuestRegisters,
                vmcs::{
                    self,
@ -76,6 +76,11 @@ impl IntelVCpu {
                VmxExitReason::HLT => {
                    //info!("VM hlt");
                }
+                VmxExitReason::CPUID => {
+                    info!("VM exit reason: CPUID");
+                    cpuid::handle_cpuid_vmexit(self);
+                    self.step_next_inst()?;
+                }
                VmxExitReason::EPT_VIOLATION => {
                    let guest_address = vmread(vmcs::ro::GUEST_PHYSICAL_ADDR_FULL)?;
                    info!("EPT Violation at guest address: {:#x}", guest_address);
@ -83,6 +88,7 @@ impl IntelVCpu {
                }
                _ => {
                    info!("VM exit reason: {:?}", exit_reason);
+                    return Err("Unhandled VM exit reason");
                }
            }
        }
@ -90,6 +96,16 @@ impl IntelVCpu {
        Ok(())
    }

+    fn step_next_inst(&mut self) -> Result<(), &'static str> {
+        use x86::vmx::vmcs;
+        let rip = vmread(vmcs::guest::RIP)?;
+        vmwrite(
+            vmcs::guest::RIP,
+            rip + vmread(vmcs::ro::VMEXIT_INSTRUCTION_LEN)?,
+        )?;
+        Ok(())
+    }
+
    fn vmentry(&mut self) -> Result<(), InstructionError> {
        let success = {
            let result: u16;