x86/vmx: Use asm goto() in _vmx_cpu_up()

With the new toolchain baseline, we can make use of asm goto() in certain
places, and the VMXON invocation is one example.

This removes the logic to set up rc (including a fixup section where bactraces
have no connection to the invoking function), the logic to decode it,
including the default case which was dead but not visibly-so to the compiler.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 0ba65becec1e1ffef7904f9e2dd05f51a51594e0..1d427100ce9fbf6f30bda4d40a3196fdf1f17e30 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -749,30 +749,15 @@ static int _vmx_cpu_up(bool bsp)
     if ( bsp && (rc = vmx_cpu_up_prepare(cpu)) != 0 )
         return rc;
 
-    switch ( __vmxon(this_cpu(vmxon_region)) )
-    {
-    case -2: /* #UD or #GP */
-        if ( bios_locked &&
-             test_bit(X86_FEATURE_SMX, &boot_cpu_data.x86_capability) &&
-             (!(eax & IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX) ||
-              !(eax & IA32_FEATURE_CONTROL_ENABLE_VMXON_INSIDE_SMX)) )
-        {
-            printk("CPU%d: VMXON failed: perhaps because of TXT settings "
-                   "in your BIOS configuration?\n", cpu);
-            printk(" --> Disable TXT in your BIOS unless using a secure "
-                   "bootloader.\n");
-            return -EINVAL;
-        }
-        /* fall through */
-    case -1: /* CF==1 or ZF==1 */
-        printk("CPU%d: unexpected VMXON failure\n", cpu);
-        return -EINVAL;
-    case 0: /* success */
-        this_cpu(vmxon) = 1;
-        break;
-    default:
-        BUG();
-    }
+    asm goto ( "1: vmxon %[addr]\n\t"
+               "   jbe %l[vmxon_fail]\n\t"
+               _ASM_EXTABLE(1b, %l[vmxon_fault])
+               :
+               : [addr] "m" (this_cpu(vmxon_region))
+               : "memory"
+               : vmxon_fail, vmxon_fault );
+
+    this_cpu(vmxon) = 1;
 
     hvm_asid_init(cpu_has_vmx_vpid ? (1u << VMCS_VPID_WIDTH) : 0);
 
@@ -785,6 +770,24 @@ static int _vmx_cpu_up(bool bsp)
     vmx_pi_per_cpu_init(cpu);
 
     return 0;
+
+ vmxon_fault:
+    if ( bios_locked &&
+         test_bit(X86_FEATURE_SMX, &boot_cpu_data.x86_capability) &&
+         (!(eax & IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX) ||
+          !(eax & IA32_FEATURE_CONTROL_ENABLE_VMXON_INSIDE_SMX)) )
+    {
+        printk(XENLOG_ERR
+               "CPU%d: VMXON failed: perhaps because of TXT settings in your BIOS configuration?\n",
+               cpu);
+        printk(XENLOG_ERR
+               " --> Disable TXT in your BIOS unless using a secure bootloader.\n");
+        return -EINVAL;
+    }
+
+ vmxon_fail:
+    printk(XENLOG_ERR "CPU%d: unexpected VMXON failure\n", cpu);
+    return -EINVAL;
 }
 
 int cf_check vmx_cpu_up(void)

diff --git a/xen/arch/x86/include/asm/hvm/vmx/vmx.h b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
index 843f8591b9cf9a9dd8b12f7261f0d22bbc3785a5..7c6ba73407445733a0c7c882ae9ff1ac7065b87c 100644 (file)
--- a/xen/arch/x86/include/asm/hvm/vmx/vmx.h
+++ b/xen/arch/x86/include/asm/hvm/vmx/vmx.h
@@ -559,25 +559,6 @@ static inline void __vmxoff(void)
         : : : "memory" );
 }
 
-static inline int __vmxon(u64 addr)
-{
-    int rc;
-
-    asm volatile ( 
-        "1: " VMXON_OPCODE MODRM_EAX_06 "\n"
-        "   setna %b0 ; neg %0\n" /* CF==1 or ZF==1 --> rc = -1 */
-        "2:\n"
-        ".section .fixup,\"ax\"\n"
-        "3: sub $2,%0 ; jmp 2b\n"    /* #UD or #GP --> rc = -2 */
-        ".previous\n"
-        _ASM_EXTABLE(1b, 3b)
-        : "=q" (rc)
-        : "0" (0), "a" (&addr)
-        : "memory");
-
-    return rc;
-}
-
 int cf_check vmx_guest_x86_mode(struct vcpu *v);
 unsigned int vmx_get_cpl(void);