x86/svm: Use named (bit)fields for task switch exit info

Introduce vmcb.ei.* to provide names to fields in exitinfo{1,2}.  Implement
the task switch names for now, and clean up the TASK_SWITCH handler.

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

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 48203c538c09c0fa7d393ff789a2d96913391e6c..fb2677b9a6bb3bcc175c0eaaf01de897c4652b96 100644 (file)
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -2748,10 +2748,7 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
         svm_vmexit_do_invalidate_cache(regs, exit_reason == VMEXIT_INVD);
         break;
 
-    case VMEXIT_TASK_SWITCH: {
-        enum hvm_task_switch_reason reason;
-        int32_t errcode = -1;
-
+    case VMEXIT_TASK_SWITCH:
         /*
          * All TASK_SWITCH intercepts have fault-like semantics.  NRIP is
          * never provided, even for instruction-induced task switches, but we
@@ -2797,19 +2794,12 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
         if ( insn_len < 0 && (insn_len = svm_get_task_switch_insn_len()) == 0 )
             goto crash_or_fault;
 
-        if ( (vmcb->exitinfo2 >> 36) & 1 )
-            reason = TSW_iret;
-        else if ( (vmcb->exitinfo2 >> 38) & 1 )
-            reason = TSW_jmp;
-        else
-            reason = TSW_call_or_int;
-        if ( (vmcb->exitinfo2 >> 44) & 1 )
-            errcode = (uint32_t)vmcb->exitinfo2;
-
-        hvm_task_switch(vmcb->exitinfo1, reason, errcode, insn_len,
-                        (vmcb->exitinfo2 & (1ul << 48)) ? X86_EFLAGS_RF : 0);
+        hvm_task_switch(vmcb->ei.task_switch.sel,
+                        vmcb->ei.task_switch.iret ? TSW_iret :
+                        vmcb->ei.task_switch.jmp  ? TSW_jmp  : TSW_call_or_int,
+                        vmcb->ei.task_switch.ev ? vmcb->ei.task_switch.ec : -1,
+                        insn_len, vmcb->ei.task_switch.rf ? X86_EFLAGS_RF : 0);
         break;
-    }
 
     case VMEXIT_CPUID:
         if ( (insn_len = svm_get_insn_len(v, INSTR_CPUID)) == 0 )

diff --git a/xen/include/asm-x86/hvm/svm/vmcb.h b/xen/include/asm-x86/hvm/svm/vmcb.h
index d2fc4d72816758ec21dcd1856201fb57b644c827..56aff9b2ea7b5335432a9c17ed128fc1d21a73cf 100644 (file)
--- a/xen/include/asm-x86/hvm/svm/vmcb.h
+++ b/xen/include/asm-x86/hvm/svm/vmcb.h
@@ -418,8 +418,28 @@ struct vmcb_struct {
     vintr_t _vintr;             /* offset 0x60 - cleanbit 3 */
     u64 interrupt_shadow;       /* offset 0x68 */
     u64 exitcode;               /* offset 0x70 */
-    u64 exitinfo1;              /* offset 0x78 */
-    u64 exitinfo2;              /* offset 0x80 */
+    union {
+        struct {
+            uint64_t exitinfo1; /* offset 0x78 */
+            uint64_t exitinfo2; /* offset 0x80 */
+        };
+        union {
+            struct {
+                uint16_t sel;
+                uint64_t :48;
+
+                uint32_t ec;
+                uint32_t :4;
+                bool     iret:1;
+                uint32_t :1;
+                bool     jmp:1;
+                uint32_t :5;
+                bool     ev:1;
+                uint32_t :3;
+                bool     rf:1;
+            } task_switch;
+        } ei;
+    };
     intinfo_t exit_int_info;    /* offset 0x88 */
     u64 _np_enable;             /* offset 0x90 - cleanbit 4 */
     u64 res08[2];