VMExit

nel_os_kernel/src/vmm/x86_64/intel/asm.rs

@@ -0,0 +1,281 @@
+use crate::vmm::x86_64::intel::{register::GuestRegisters, vcpu::IntelVCpu};
+use core::{arch::global_asm, mem::offset_of};
+
+#[allow(improper_ctypes)]
+unsafe extern "C" {
+    pub unsafe fn asm_vm_entry(vcpu: *mut IntelVCpu) -> u16;
+    pub unsafe fn asm_vmexit_handler() -> !;
+}
+
+global_asm!(
+".global asm_vm_entry",
+".type asm_vm_entry, @function",
+"asm_vm_entry:", // rdi = *VCpu
+"push rbp",
+"push r15",
+"push r14",
+"push r13",
+"push r12",
+"push rbx",
+/*
+   stack:
+   +-----+
+   | RBX |
+   +-----+
+   | R12 |
+   +-----+
+   | R13 |
+   +-----+
+   | R14 |
+   +-----+
+   | R15 |
+   +-----+
+   | RBP |
+   +-----+
+   | RIP |
+   +-----+
+
+   regs:
+   RDI = *VCpu
+   */
+
+"lea rbx, [rdi + {guest_regs_offset}]", // rbx = *guest_regs
+"push rbx", // push *guest_regs
+"push rdi", // push *VCpu
+"lea rdi, [rsp + 8]", // rdi = rsp + 8 = *guest_regs
+"call set_host_stack",
+"pop rdi", // rdi = *VCpu
+"test byte ptr [rdi + {launch_done_offset}], 1", // flag = launch_done ? 1 : 0
+/*
+   stack:
+   +-------------+
+   | *guest_regs |
+   +-------------+
+   |     RBX     |
+   +-------------+
+   |     R12     |
+   +-------------+
+   |     R13     |
+   +-------------+
+   |     R14     |
+   +-------------+
+   |     R15     |
+   +-------------+
+   |     RBP     |
+   +-------------+
+   |     RIP     |
+   +-------------+
+   regs:
+   RDI = *VCpu
+   RBX = *guest_regs
+   */
+"mov rax, rbx", // rax = *guest_regs
+"mov rcx, [rax+{reg_offset_rcx}]", // rcx = guest_regs.rcx
+"mov rdx, [rax+{reg_offset_rdx}]", // rdx = guest_regs.rdx
+"mov rbx, [rax+{reg_offset_rbx}]", // rbx = guest_regs.rbx
+"mov rsi, [rax+{reg_offset_rsi}]    ", // rsi = guest_regs.rsi
+
+"mov rdi, [rax+{reg_offset_rdi}]", // rdi = guest_regs.rdi
+"mov rbp, [rax+{reg_offset_rbp}]", // rbp = guest_regs.rbp
+"mov r8, [rax+{reg_offset_r8}]", // r8 = guest_regs.r8
+"mov r9, [rax+{reg_offset_r9}]", // r9 = guest_regs.r9
+
+"mov r10, [rax+{reg_offset_r10}]", // r10 = guest_regs.r10
+"mov r11, [rax+{reg_offset_r11}]", // r11 = guest_regs.r11
+"mov r12, [rax+{reg_offset_r12}]", // r12 = guest_regs.r12
+"mov r13, [rax+{reg_offset_r13}]", // r13 = guest_regs.r13
+"mov r14, [rax+{reg_offset_r14}]", // r14 = guest_regs.r14
+"mov r15, [rax+{reg_offset_r15}]", // r15 = guest_regs.r15
+"movaps xmm0, [rax+{reg_offset_xmm0}]", // xmm0 = guest_regs.xmm0
+"movaps xmm1, [rax+{reg_offset_xmm1}]", // xmm1 = guest_regs.xmm1
+"movaps xmm2, [rax+{reg_offset_xmm2}]", // xmm2 = guest_regs.xmm2
+"movaps xmm3, [rax+{reg_offset_xmm3}]", // xmm3 = guest_regs.xmm3
+"movaps xmm4, [rax+{reg_offset_xmm4}]", // xmm4 = guest_regs.xmm4
+"movaps xmm5, [rax+{reg_offset_xmm5}]", // xmm5 = guest_regs.xmm5
+"movaps xmm6, [rax+{reg_offset_xmm6}]", // xmm6 = guest_regs.xmm6
+"movaps xmm7, [rax+{reg_offset_xmm7}]", // xmm7 = guest_regs.xmm7
+"mov rax, [rax+{reg_offset_rax}]", // rax = guest_regs.rax
+/*
+   stack:
+   +-------------+
+   | *guest_regs |
+   +-------------+
+   |     RBX     |
+   +-------------+
+   |     R12     |
+   +-------------+
+   |     R13     |
+   +-------------+
+   |     R14     |
+   +-------------+
+   |     R15     |
+   +-------------+
+   |     RBP     |
+   +-------------+
+   |     RIP     |
+   +-------------+
+   */
+"jz 2f",
+"vmresume",
+"2:",
+"vmlaunch",
+"mov ax, 1",
+"add rsp, 0x8",
+"pop rbx",
+"pop r12",
+"pop r13",
+"pop r14",
+"pop r15",
+"pop rbp",
+"ret",
+
+".size asm_vm_entry, . - asm_vm_entry",
+
+".global asm_vmexit_handler",
+".type asm_vmexit_handler, @function",
+"asm_vmexit_handler:",
+"cli",
+/*
+   stack:
+   +-------------+
+   | *guest_regs |
+   +-------------+
+   |     RBX     |
+   +-------------+
+   |     R12     |
+   +-------------+
+   |     R13     |
+   +-------------+
+
+   |     R14     |
+   +-------------+
+   |     R15     |
+   +-------------+
+   |     RBP     |
+   +-------------+
+   |     RIP     |
+   +-------------+
+
+   regs:
+   RAX = guest CPU's rax
+   */
+"push rax",
+"mov rax, qword ptr [rsp + 0x8]", // rax = *guest_regs
+/*
+   stack:
+   +-------------+
+
+   |  guest RAX  |
+   +-------------+
+   | *guest_regs |
+   +-------------+
+   |     RBX     |
+   +-------------+
+   |     R12     |
+   +-------------+
+   |     R13     |
+   +-------------+
+   |     R14     |
+   +-------------+
+   |     R15     |
+
+   +-------------+
+   |     RBP     |
+   +-------------+
+   |     RIP     |
+   +-------------+
+   */
+
+
+"pop [rax + {reg_offset_rax}]", // guest_regs.rax = guest CPU's rax
+"add rsp, 0x8", // discard *guest_regs
+/*
+   stack:
+   +-------------+
+   |     RBX     |
+   +-------------+
+   |     R12     |
+   +-------------+
+   |     R13     |
+   +-------------+
+   |     R14     |
+   +-------------+
+   |     R15     |
+   +-------------+
+   |     RBP     |
+   +-------------+
+   |     RIP     |
+   +-------------+
+   */
+
+// save rcx, rdx, rbx, rsi, rdi, rbp, r8~15, xmm0~7
+"mov [rax + {reg_offset_rcx}], rcx",
+"mov [rax + {reg_offset_rdx}], rdx",
+"mov [rax + {reg_offset_rbx}], rbx",
+"mov [rax + {reg_offset_rsi}], rsi",
+
+"mov [rax + {reg_offset_rdi}], rdi",
+"mov [rax + {reg_offset_rbp}], rbp",
+"mov [rax + {reg_offset_r8}], r8",
+"mov [rax + {reg_offset_r9}], r9",
+"mov [rax + {reg_offset_r10}], r10",
+"mov [rax + {reg_offset_r11}], r11",
+"mov [rax + {reg_offset_r12}], r12",
+"mov [rax + {reg_offset_r13}], r13",
+"mov [rax + {reg_offset_r14}], r14",
+"mov [rax + {reg_offset_r15}], r15",
+
+"movaps [rax + {reg_offset_xmm0}], xmm0",
+"movaps [rax + {reg_offset_xmm1}], xmm1",
+"movaps [rax + {reg_offset_xmm2}], xmm2",
+"movaps [rax + {reg_offset_xmm3}], xmm3",
+"movaps [rax + {reg_offset_xmm4}], xmm4",
+"movaps [rax + {reg_offset_xmm5}], xmm5",
+"movaps [rax + {reg_offset_xmm6}], xmm6",
+"movaps [rax + {reg_offset_xmm7}], xmm7",
+"pop rbx",
+"pop r12",
+"pop r13",
+"pop r14",
+"pop r15",
+"pop rbp",
+/*
+
+   stack:
+   +-------------+
+   |     RIP     |
+   +-------------+
+   */
+"mov rax, 0x0",
+"ret",
+
+
+".size asm_vmexit_handler, . - asm_vmexit_handler",
+
+guest_regs_offset = const offset_of!(IntelVCpu, guest_registers),
+launch_done_offset = const offset_of!(IntelVCpu, launch_done),
+reg_offset_rax = const offset_of!(GuestRegisters, rax),
+reg_offset_rcx = const offset_of!(GuestRegisters, rcx),
+reg_offset_rdx = const offset_of!(GuestRegisters, rdx),
+reg_offset_rbx = const offset_of!(GuestRegisters, rbx),
+reg_offset_rsi = const offset_of!(GuestRegisters, rsi),
+reg_offset_rdi = const offset_of!(GuestRegisters, rdi),
+reg_offset_rbp = const offset_of!(GuestRegisters, rbp),
+reg_offset_r8 = const offset_of!(GuestRegisters, r8),
+
+reg_offset_r9 = const offset_of!(GuestRegisters, r9),
+reg_offset_r10 = const offset_of!(GuestRegisters, r10),
+reg_offset_r11 = const offset_of!(GuestRegisters, r11),
+reg_offset_r12 = const offset_of!(GuestRegisters, r12),
+reg_offset_r13 = const offset_of!(GuestRegisters, r13),
+reg_offset_r14 = const offset_of!(GuestRegisters, r14),
+reg_offset_r15 = const offset_of!(GuestRegisters, r15),
+reg_offset_xmm0 = const offset_of!(GuestRegisters, xmm0),
+reg_offset_xmm1 = const offset_of!(GuestRegisters, xmm1),
+reg_offset_xmm2 = const offset_of!(GuestRegisters, xmm2),
+reg_offset_xmm3 = const offset_of!(GuestRegisters, xmm3),
+reg_offset_xmm4 = const offset_of!(GuestRegisters, xmm4),
+reg_offset_xmm5 = const offset_of!(GuestRegisters, xmm5),
+reg_offset_xmm6 = const offset_of!(GuestRegisters, xmm6),
+reg_offset_xmm7 = const offset_of!(GuestRegisters, xmm7),
+);

nel_os_kernel/src/vmm/x86_64/intel/mod.rs

@@ -1,3 +1,4 @@
+mod asm;
 mod controls;
 mod register;
 pub mod vcpu;

nel_os_kernel/src/vmm/x86_64/intel/vcpu.rs

@@ -4,6 +4,7 @@ use raw_cpuid::cpuid;
 use x86_64::{
     registers::control::Cr4Flags,
     structures::paging::{FrameAllocator, Size4KiB},
+    VirtAddr,
 };
 
 use crate::{
@@ -25,6 +26,9 @@ use crate::{
     },
 };
 
+const TEMP_STACK_SIZE: usize = 4096;
+static mut TEMP_STACK: [u8; TEMP_STACK_SIZE + 0x10] = [0; TEMP_STACK_SIZE + 0x10];
+
 #[repr(C)]
 pub struct IntelVCpu {
     pub launch_done: bool,
@@ -64,7 +68,14 @@ impl IntelVCpu {
             unsafe { cr4() }.bits() as u64 | Cr4Flags::OSXSAVE.bits(),
         )?;
 
-        // TODO: set RIP to VMExit handler and stack
+        vmwrite(
+            vmcs::host::RIP,
+            crate::vmm::x86_64::intel::asm::asm_vmexit_handler as u64,
+        )?;
+        vmwrite(
+            vmcs::host::RSP,
+            VirtAddr::from_ptr(&raw mut TEMP_STACK).as_u64() + TEMP_STACK_SIZE as u64,
+        )?;
 
         vmwrite(vmcs::host::ES_SELECTOR, es().bits() as u64)?;
         vmwrite(vmcs::host::CS_SELECTOR, cs().bits() as u64)?;