x86/vmx: improvements to vmentry failure handling

Combine the almost identical vm_launch_fail() and vm_resume_fail() into a
single vmx_vmentry_failure().

Re-save all GPRs so that domain_crash() prints the real register values,
rather than the stack frame of the vmx_vmentry_failure() call.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>

xen/arch/x86/hvm/vmx/entry.S

@@ -101,14 +101,15 @@ UNLIKELY_END(realmode)
 
 /*.Lvmx_resume:*/
         VMRESUME
-        sti
-        call vm_resume_fail
-        ud2
+        jmp  .Lvmx_vmentry_fail
 
 .Lvmx_launch:
         VMLAUNCH
+
+.Lvmx_vmentry_fail:
         sti
-        call vm_launch_fail
+        SAVE_ALL
+        call vmx_vmentry_failure
         ud2
 
 ENTRY(vmx_asm_do_vmentry)

xen/arch/x86/hvm/vmx/vmcs.c

@@ -1612,21 +1612,14 @@ void vmx_destroy_vmcs(struct vcpu *v)
     free_xenheap_page(v->arch.hvm_vmx.msr_bitmap);
 }
 
-void vm_launch_fail(void)
+void vmx_vmentry_failure(void)
 {
+    struct vcpu *curr = current;
     unsigned long error;
 
     __vmread(VM_INSTRUCTION_ERROR, &error);
-    printk("<vm_launch_fail> error code %lx\n", error);
-    domain_crash_synchronous();
-}
-
-void vm_resume_fail(void)
-{
-    unsigned long error;
-
-    __vmread(VM_INSTRUCTION_ERROR, &error);
-    printk("<vm_resume_fail> error code %lx\n", error);
+    gprintk(XENLOG_ERR, "VM%s error: %#lx\n",
+            curr->arch.hvm_vmx.launched ? "RESUME" : "LAUNCH", error);
     domain_crash_synchronous();
 }