[PATCH] x86/vmx: Provide named fields for IO exit qualification

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This removes most of the opencoded bit logic on the exit qualification.
Unfortunately, size is 1-based not 0-based, so need adjusting in a separate
variable.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 00b531f76cbf..a96c601efded 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -4560,23 +4560,37 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
         break;
 
     case EXIT_REASON_IO_INSTRUCTION:
-        __vmread(EXIT_QUALIFICATION, &exit_qualification);
-        if ( exit_qualification & 0x10 )
+    {
+        union {
+            unsigned long raw;
+            struct {
+                uint32_t size:3;
+                bool     in:1;
+                bool     str:1;
+                bool     rep:1;
+                bool     imm:1;
+                uint32_t :9;
+                uint16_t port;
+            };
+        } io_qual;
+        unsigned int bytes;
+
+        __vmread(EXIT_QUALIFICATION, &io_qual.raw);
+        bytes = io_qual.size + 1;
+
+        if ( io_qual.str )
         {
-            /* INS, OUTS */
             if ( !hvm_emulate_one_insn(x86_insn_is_portio, "port I/O") )
                 hvm_inject_hw_exception(TRAP_gp_fault, 0);
         }
         else
         {
-            /* IN, OUT */
-            uint16_t port = (exit_qualification >> 16) & 0xFFFF;
-            int bytes = (exit_qualification & 0x07) + 1;
-            int dir = (exit_qualification & 0x08) ? IOREQ_READ : IOREQ_WRITE;
-            if ( handle_pio(port, bytes, dir) )
+            if ( handle_pio(io_qual.port, bytes,
+                            io_qual.in ? IOREQ_READ : IOREQ_WRITE) )
                 update_guest_eip(); /* Safe: IN, OUT */
         }
         break;
+    }
 
     case EXIT_REASON_INVD:
     case EXIT_REASON_WBINVD:
-- 
2.30.2