Generate #UD exception for unsupported instructions which cause vm-exits,

instead of terminating the guest.

Signed-off-by: Alexey Romko <nevilad@yahoo.com>

Author: nevilad

core/include/vmx.h

@@ -58,16 +58,16 @@ enum {
     VMX_EXIT_RDPMC                   = 15, // Guest executed RDPMC instruction
     VMX_EXIT_RDTSC                   = 16, // Guest executed RDTSC instruction
     VMX_EXIT_RSM                     = 17, // Guest executed RSM instruction in SMM
-    VMX_EXIT_VMCALL                  = 18,
-    VMX_EXIT_VMCLEAR                 = 19,
-    VMX_EXIT_VMLAUNCH                = 20,
-    VMX_EXIT_VMPTRLD                 = 21,
-    VMX_EXIT_VMPTRST                 = 22,
-    VMX_EXIT_VMREAD                  = 23,
-    VMX_EXIT_VMRESUME                = 24,
-    VMX_EXIT_VMWRITE                 = 25,
-    VMX_EXIT_VMXOFF                  = 26,
-    VMX_EXIT_VMXON                   = 27,
+    VMX_EXIT_VMCALL                  = 18, // Guest executed VMCALL instruction
+    VMX_EXIT_VMCLEAR                 = 19, // Guest executed VMCLEAR instruction
+    VMX_EXIT_VMLAUNCH                = 20, // Guest executed VMLAUNCH instruction
+    VMX_EXIT_VMPTRLD                 = 21, // Guest executed VMPTRLD instruction
+    VMX_EXIT_VMPTRST                 = 22, // Guest executed VMPTRST instruction
+    VMX_EXIT_VMREAD                  = 23, // Guest executed VMREAD instruction
+    VMX_EXIT_VMRESUME                = 24, // Guest executed VMRESUME instruction
+    VMX_EXIT_VMWRITE                 = 25, // Guest executed VMWRITE instruction
+    VMX_EXIT_VMXOFF                  = 26, // Guest executed VMXON instruction
+    VMX_EXIT_VMXON                   = 27, // Guest executed VMXOFF instruction
     VMX_EXIT_CR_ACCESS               = 28, // Guest accessed a control register
     VMX_EXIT_DR_ACCESS               = 29, // Guest attempted access to debug register
     VMX_EXIT_IO                      = 30, // Guest attempted I/O
@@ -91,7 +91,7 @@ enum {
     VMX_EXIT_VMX_TIMER_EXIT          = 52,
     VMX_EXIT_INVVPID                 = 53,
     VMX_EXIT_WBINVD                  = 54,
-    VMX_EXIT_XSETBV                  = 55,
+    VMX_EXIT_XSETBV                  = 55, // Guest executed XSETBV instruction
     VMX_EXIT_APIC_WRITE              = 56,
     VMX_EXIT_RDRAND                  = 57,
     VMX_EXIT_INVPCID                 = 58,

core/vcpu.c

@@ -100,6 +100,8 @@ static int exit_invalid_guest_state(struct vcpu_t *vcpu,
 static int exit_ept_misconfiguration(struct vcpu_t *vcpu,
                                      struct hax_tunnel *htun);
 static int exit_ept_violation(struct vcpu_t *vcpu, struct hax_tunnel *htun);
+static int exit_unsupported_instruction(struct vcpu_t *vcpu, 
+                                        struct hax_tunnel *htun);
 static int null_handler(struct vcpu_t *vcpu, struct hax_tunnel *hun);
 
 static void advance_rip(struct vcpu_t *vcpu);
@@ -388,6 +390,22 @@ static int (*handler_funcs[])(struct vcpu_t *vcpu, struct hax_tunnel *htun) = {
     [VMX_EXIT_FAILED_VMENTER_GS]  = exit_invalid_guest_state,
     [VMX_EXIT_EPT_VIOLATION]      = exit_ept_violation,
     [VMX_EXIT_EPT_MISCONFIG]      = exit_ept_misconfiguration,
+    [VMX_EXIT_GETSEC]             = exit_unsupported_instruction,
+    [VMX_EXIT_INVD]               = exit_unsupported_instruction,
+    [VMX_EXIT_VMCALL]             = exit_unsupported_instruction,
+    [VMX_EXIT_VMCLEAR]            = exit_unsupported_instruction,
+    [VMX_EXIT_VMLAUNCH]           = exit_unsupported_instruction,
+    [VMX_EXIT_VMPTRLD]            = exit_unsupported_instruction,
+    [VMX_EXIT_VMPTRST]            = exit_unsupported_instruction,
+    //VMREAD and VMWRITE vm-exits are conditional. When "VMCS shadowing" bit
+    //in secondary CPU VM-execution control is 0, these exit. This condition
+    //holds in haxm.
+    [VMX_EXIT_VMREAD]             = exit_unsupported_instruction,
+    [VMX_EXIT_VMWRITE]            = exit_unsupported_instruction,
+    [VMX_EXIT_VMRESUME]           = exit_unsupported_instruction,
+    [VMX_EXIT_VMXOFF]             = exit_unsupported_instruction,
+    [VMX_EXIT_VMXON]              = exit_unsupported_instruction,
+    [VMX_EXIT_XSETBV]             = exit_unsupported_instruction,
 };
 
 static int nr_handlers = ARRAY_ELEMENTS(handler_funcs);
@@ -3882,6 +3900,13 @@ static int exit_ept_violation(struct vcpu_t *vcpu, struct hax_tunnel *htun)
     return vcpu_emulate_insn(vcpu);
 }
 
+static int exit_unsupported_instruction(struct vcpu_t *vcpu, 
+                                        struct hax_tunnel *htun)
+{
+    hax_inject_exception(vcpu, VECTOR_UD, NO_ERROR_CODE);
+    return HAX_RESUME;
+}
+
 static void handle_mem_fault(struct vcpu_t *vcpu, struct hax_tunnel *htun)
 {
     hax_log(HAX_LOGW,