FUCK

2026-07-28 12:00:02 +08:00
parent efa626ed17
commit 17a577f2ed
51 changed files with 8446 additions and 787 deletions
@@ -0,0 +1,90 @@
+/* VM-Exit assembly entry.
+ *
+ * On VM-Exit, CPU loads host state from VMCS:
+ *   - host CR0/CR3/CR4, segment registers
+ *   - host RSP = VMCS_HOST_RSP (top of g_host_stack)
+ *   - host RIP = VMCS_HOST_RIP (this function)
+ *
+ * VMCS does NOT save guest GPRs (RAX-R15). They remain in the CPU registers
+ * and must be saved explicitly if the C dispatcher wants to read or modify
+ * them (e.g. for VMCALL hypercall arguments and return values).
+ *
+ * This function:
+ *   1. Saves all 16 guest GPRs into g_guest_regs
+ *   2. Calls vmm_vmexit_entry() (C dispatcher, returns void)
+ *      - Internally calls vmexit_dispatch(); sets g_guest_terminated if !resume
+ *   3. Restores all 16 guest GPRs from g_guest_regs (C may have modified rax)
+ *   4. Checks g_guest_terminated:
+ *      - 0: executes vmresume (GPRs = guest values, possibly modified by C)
+ *           If vmresume fails, falls through to terminate
+ *      - 1: restores saved host RSP, jmps to saved return RIP
+ *
+ * The saved RSP/RIP point into the vmlaunch inline asm block (in vmm_self_test
+ * or linux_launch). After the jmp, C flow continues with failed=0.
+ */
+
+.section .text
+.global vmx_vm_exit_handler
+vmx_vm_exit_handler:
+    /* Step 1: Save all 16 guest GPRs to g_guest_regs.
+     * GPRs at this point hold guest values (VMCS doesn't save them). */
+    movq %rax,  g_guest_regs + 0(%rip)
+    movq %rbx,  g_guest_regs + 8(%rip)
+    movq %rcx,  g_guest_regs + 16(%rip)
+    movq %rdx,  g_guest_regs + 24(%rip)
+    movq %rsi,  g_guest_regs + 32(%rip)
+    movq %rdi,  g_guest_regs + 40(%rip)
+    movq %rbp,  g_guest_regs + 48(%rip)
+    movq %r8,   g_guest_regs + 56(%rip)
+    movq %r9,   g_guest_regs + 64(%rip)
+    movq %r10,  g_guest_regs + 72(%rip)
+    movq %r11,  g_guest_regs + 80(%rip)
+    movq %r12,  g_guest_regs + 88(%rip)
+    movq %r13,  g_guest_regs + 96(%rip)
+    movq %r14,  g_guest_regs + 104(%rip)
+    movq %r15,  g_guest_regs + 112(%rip)
+
+    /* Step 2: Align stack to 16 bytes and call C dispatcher.
+     * The host RSP (from VMCS_HOST_RSP) is 16-byte aligned minus 8
+     * (for the implicit return address), so we sub 8 for alignment. */
+    subq $8, %rsp
+    call vmm_vmexit_entry
+    addq $8, %rsp
+
+    /* Step 3: Restore all 16 guest GPRs from g_guest_regs.
+     * C handlers may have modified fields (e.g. rax = hypercall return value). */
+    movq  g_guest_regs + 0(%rip), %rax
+    movq  g_guest_regs + 8(%rip), %rbx
+    movq  g_guest_regs + 16(%rip), %rcx
+    movq  g_guest_regs + 24(%rip), %rdx
+    movq  g_guest_regs + 32(%rip), %rsi
+    movq  g_guest_regs + 40(%rip), %rdi
+    movq  g_guest_regs + 48(%rip), %rbp
+    movq  g_guest_regs + 56(%rip), %r8
+    movq  g_guest_regs + 64(%rip), %r9
+    movq  g_guest_regs + 72(%rip), %r10
+    movq  g_guest_regs + 80(%rip), %r11
+    movq  g_guest_regs + 88(%rip), %r12
+    movq  g_guest_regs + 96(%rip), %r13
+    movq  g_guest_regs + 104(%rip), %r14
+    movq  g_guest_regs + 112(%rip), %r15
+
+    /* Step 4: Check terminate flag */
+    movl g_guest_terminated(%rip), %eax
+    testl %eax, %eax
+    jnz .Lterminate
+
+    /* Resume guest: GPRs are now restored (with any C modifications).
+     * vmresume does not return on success — CPU enters guest. */
+    vmresume
+    /* If we reach here, vmresume failed (CF=1 or ZF=1). */
+    movl $1, g_guest_terminated(%rip)
+    /* Fall through to terminate */
+
+.Lterminate:
+    /* Terminate: restore saved RSP and jmp to saved return RIP.
+     * The saved RSP is the caller's stack pointer before vmlaunch.
+     * The saved RIP is the "1:" label in the vmlaunch inline asm,
+     * which sets failed=0 and continues C flow. */
+    movq g_saved_host_rsp(%rip), %rsp
+    jmpq *g_saved_return_rip(%rip)