VMM: Add kernel support for VM contexts [1/2]
[akaros.git] / kern / arch / x86 / trap.c
index 876c3b2..6cb72cb 100644 (file)
@@ -676,3 +676,191 @@ void send_ipi(uint32_t os_coreid, uint8_t vector)
        }
        __send_ipi(hw_coreid, vector);
 }
+
+/****************** VM exit handling ******************/
+
+static bool handle_vmexit_cpuid(struct vm_trapframe *tf)
+{
+       uint32_t eax, ebx, ecx, edx;
+
+       cpuid(tf->tf_rax, tf->tf_rcx, &eax, &ebx, &ecx, &edx);
+       tf->tf_rax = eax;
+       tf->tf_rbx = ebx;
+       tf->tf_rcx = ecx;
+       tf->tf_rdx = edx;
+       tf->tf_rip += 2;
+       return TRUE;
+}
+
+static bool handle_vmexit_ept_fault(struct vm_trapframe *tf)
+{
+       int prot = 0;
+       int ret;
+
+       prot |= tf->tf_exit_qual & VMX_EPT_FAULT_READ ? PROT_READ : 0;
+       prot |= tf->tf_exit_qual & VMX_EPT_FAULT_WRITE ? PROT_WRITE : 0;
+       prot |= tf->tf_exit_qual & VMX_EPT_FAULT_INS ? PROT_EXEC : 0;
+       ret = handle_page_fault(current, tf->tf_guest_pa, prot);
+       if (ret) {
+               /* TODO: maybe put ret in the TF somewhere */
+               return FALSE;
+       }
+       return TRUE;
+}
+
+static bool handle_vmexit_nmi(struct vm_trapframe *tf)
+{
+       /* Sanity checks, make sure we really got an NMI.  Feel free to remove. */
+       assert((tf->tf_intrinfo2 & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR);
+       assert((tf->tf_intrinfo2 & INTR_INFO_VECTOR_MASK) == T_NMI);
+       /* our NMI handler from trap.c won't run.  but we don't need the lock
+        * disabling stuff. */
+       extern bool mon_verbose_trace;
+
+       if (mon_verbose_trace) {
+               print_vmtrapframe(tf);
+               /* TODO: a backtrace of the guest would be nice here. */
+       }
+       printk("Core %d is at %p\n", core_id(), get_vmtf_pc(tf));
+       return TRUE;
+}
+
+bool handle_vmexit_msr(struct vm_trapframe *tf)
+{
+       bool ret;
+
+       ret = vmm_emulate_msr(&tf->tf_rcx, &tf->tf_rdx, &tf->tf_rax,
+                             (tf->tf_exit_reason == EXIT_REASON_MSR_READ
+                                                  ? VMM_MSR_EMU_READ : VMM_MSR_EMU_WRITE));
+       if (ret)
+               tf->tf_rip += 2;
+       return ret;
+}
+
+bool handle_vmexit_extirq(struct vm_trapframe *tf)
+{
+       struct hw_trapframe hw_tf;
+
+       /* For now, we just handle external IRQs.  I think guest traps should go to
+        * the guest, based on our vmctls */
+       assert((tf->tf_intrinfo2 & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_EXT_INTR);
+       /* TODO: Our IRQ handlers all expect TFs.  Let's fake one.  A bunch of
+        * handlers (e.g. backtrace/perf) will probably be unhappy about a user TF
+        * that is really a VM, so this all needs work. */
+       hw_tf.tf_gsbase = 0;
+       hw_tf.tf_fsbase = 0;
+       hw_tf.tf_rax = tf->tf_rax;
+       hw_tf.tf_rbx = tf->tf_rbx;
+       hw_tf.tf_rcx = tf->tf_rcx;
+       hw_tf.tf_rdx = tf->tf_rdx;
+       hw_tf.tf_rbp = tf->tf_rbp;
+       hw_tf.tf_rsi = tf->tf_rsi;
+       hw_tf.tf_rdi = tf->tf_rdi;
+       hw_tf.tf_r8 = tf->tf_r8;
+       hw_tf.tf_r9 = tf->tf_r9;
+       hw_tf.tf_r10 = tf->tf_r10;
+       hw_tf.tf_r11 = tf->tf_r11;
+       hw_tf.tf_r12 = tf->tf_r12;
+       hw_tf.tf_r13 = tf->tf_r13;
+       hw_tf.tf_r14 = tf->tf_r14;
+       hw_tf.tf_r15 = tf->tf_r15;
+       hw_tf.tf_trapno = tf->tf_intrinfo2 & INTR_INFO_VECTOR_MASK;
+       hw_tf.tf_err = 0;
+       hw_tf.tf_rip = tf->tf_rip;
+       hw_tf.tf_cs = GD_UT;    /* faking a user TF, even though it's a VM */
+       hw_tf.tf_rflags = tf->tf_rflags;
+       hw_tf.tf_rsp = tf->tf_rsp;
+       hw_tf.tf_ss = GD_UD;
+
+       irq_dispatch(&hw_tf);
+       /* Consider returning whether or not there was a handler registered */
+       return TRUE;
+}
+
+static void vmexit_dispatch(struct vm_trapframe *tf)
+{
+       bool handled = FALSE;
+
+       /* Do not block in any of these functions.
+        *
+        * If we block, we'll probably need to finalize the context.  If we do, then
+        * there's a chance the guest pcore can start somewhere else, and then we
+        * can't get the GPC loaded again.  Plus, they could be running a GPC with
+        * an unresolved vmexit.  It's just mess.
+        *
+        * If we want to enable IRQs, we can do so on a case-by-case basis.  Don't
+        * do it for external IRQs - the irq_dispatch code will handle it. */
+       switch (tf->tf_exit_reason) {
+       case EXIT_REASON_VMCALL:
+               if (current->vmm.flags & VMM_VMCALL_PRINTF) {
+                       printk("%c", tf->tf_rdi);
+                       tf->tf_rip += 3;
+                       handled = TRUE;
+               }
+               break;
+       case EXIT_REASON_CPUID:
+               handled = handle_vmexit_cpuid(tf);
+               break;
+       case EXIT_REASON_EPT_VIOLATION:
+               handled = handle_vmexit_ept_fault(tf);
+               break;
+       case EXIT_REASON_EXCEPTION_NMI:
+               handled = handle_vmexit_nmi(tf);
+               break;
+       case EXIT_REASON_MSR_READ:
+       case EXIT_REASON_MSR_WRITE:
+               handled = handle_vmexit_msr(tf);
+               break;
+       case EXIT_REASON_EXTERNAL_INTERRUPT:
+               handled = handle_vmexit_extirq(tf);
+               break;
+       default:
+               printd("Unhandled vmexit: reason 0x%x, exit qualification 0x%x\n",
+                      tf->tf_exit_reason, tf->tf_exit_qual);
+       }
+       if (!handled) {
+               tf->tf_flags |= VMCTX_FL_HAS_FAULT;
+               if (reflect_current_context()) {
+                       /* VM contexts shouldn't be in vcore context, so this should be
+                        * pretty rare (unlike SCPs or VC ctx page faults). */
+                       printk("[kernel] Unable to reflect VM Exit\n");
+                       print_vmtrapframe(tf);
+                       proc_destroy(current);
+               }
+       }
+}
+
+void handle_vmexit(struct vm_trapframe *tf)
+{
+       struct per_cpu_info *pcpui = &per_cpu_info[core_id()];
+
+       tf->tf_rip = vmcs_read(GUEST_RIP);
+       tf->tf_rflags = vmcs_read(GUEST_RFLAGS);
+       tf->tf_rsp = vmcs_read(GUEST_RSP);
+       tf->tf_cr2 = rcr2();
+       tf->tf_cr3 = vmcs_read(GUEST_CR3);
+       tf->tf_guest_pcoreid = pcpui->guest_pcoreid;
+       tf->tf_flags |= VMCTX_FL_PARTIAL;
+       tf->tf_exit_reason = vmcs_read(VM_EXIT_REASON);
+       tf->tf_exit_qual = vmcs_read(EXIT_QUALIFICATION);
+       tf->tf_intrinfo1 = vmcs_read(GUEST_INTERRUPTIBILITY_INFO);
+       tf->tf_intrinfo2 = vmcs_read(VM_EXIT_INTR_INFO);
+       tf->tf_guest_va = vmcs_read(GUEST_LINEAR_ADDRESS);
+       tf->tf_guest_pa = vmcs_read(GUEST_PHYSICAL_ADDRESS);
+
+       set_current_ctx_vm(pcpui, tf);
+       tf = &pcpui->cur_ctx->tf.vm_tf;
+       vmexit_dispatch(tf);
+       /* We're either restarting a partial VM ctx (vmcs was launched, loaded on
+        * the core, etc) or a SW vc ctx for the reflected trap.  Or the proc is
+        * dying and we'll handle a __death KMSG shortly. */
+       proc_restartcore();
+}
+
+void x86_finalize_vmtf(struct vm_trapframe *tf)
+{
+       struct per_cpu_info *pcpui = &per_cpu_info[core_id()];
+
+       x86_vmtf_clear_partial(tf);
+       unload_guest_pcore(pcpui->cur_proc, pcpui->guest_pcoreid);
+}