[RFC V0 PATCH 1/1] Replace handle_mmio calls in svm/vmx

[Mukesh Rathor <mukesh.rathor@oracle.com>]

svm/vmx IO and CR intercepts call handle_mmio to emulate which
is slightly inappropriate.  Create hvm_emulate() and replace those
calls with hvm_emulate().

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/hvm/emulate.c        | 26 ++++++++++++++++++++++++++
 xen/arch/x86/hvm/svm/svm.c        | 12 ++++++------
 xen/arch/x86/hvm/vmx/vmx.c        | 10 +++-------
 xen/include/asm-x86/hvm/emulate.h |  1 +
 4 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index eac159f..c568196 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -1252,6 +1252,32 @@ void hvm_emulate_prepare(
     hvmemul_get_seg_reg(x86_seg_ss, hvmemul_ctxt);
 }
 
+void hvm_emulate(struct cpu_user_regs *regs)
+{
+    int rc;
+    struct hvm_emulate_ctxt ctxt;
+    
+    hvm_emulate_prepare(&ctxt, regs);
+    rc = hvm_emulate_one(&ctxt);
+    
+    switch ( rc )
+    {
+    case X86EMUL_UNHANDLEABLE:
+        hvm_inject_hw_exception(TRAP_gp_fault, 0);
+        break;
+    case X86EMUL_EXCEPTION:
+    {
+        uint8_t vector = ctxt.exn_pending ? ctxt.exn_vector : TRAP_gp_fault;
+        int32_t errcode = ctxt.exn_pending ? ctxt.exn_error_code : 0;
+        hvm_inject_hw_exception(vector, errcode);
+        /* fall thru */
+    }
+    default:
+        hvm_emulate_writeback(&ctxt);
+        break;
+    }
+}       
+
 void hvm_emulate_writeback(
     struct hvm_emulate_ctxt *hvmemul_ctxt)
 {
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 89df9f7..6c24ad2 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -2475,16 +2475,16 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
             if ( handle_pio(port, bytes, dir) )
                 __update_guest_eip(regs, vmcb->exitinfo2 - vmcb->rip);
         }
-        else if ( !handle_mmio() )
-            hvm_inject_hw_exception(TRAP_gp_fault, 0);
+        else 
+            hvm_emulate(regs);
         break;
 
     case VMEXIT_CR0_READ ... VMEXIT_CR15_READ:
     case VMEXIT_CR0_WRITE ... VMEXIT_CR15_WRITE:
         if ( cpu_has_svm_decode && (vmcb->exitinfo1 & (1ULL << 63)) )
             svm_vmexit_do_cr_access(vmcb, regs);
-        else if ( !handle_mmio() ) 
-            hvm_inject_hw_exception(TRAP_gp_fault, 0);
+        else
+            hvm_emulate(regs);
         break;
 
     case VMEXIT_INVLPG:
@@ -2493,8 +2493,8 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
             svm_invlpg_intercept(vmcb->exitinfo1);
             __update_guest_eip(regs, vmcb->nextrip - vmcb->rip);
         }
-        else if ( !handle_mmio() )
-            hvm_inject_hw_exception(TRAP_gp_fault, 0);
+        else
+            hvm_emulate(regs);
         break;
 
     case VMEXIT_INVLPGA:
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index dd969dc..415b73e 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3008,8 +3008,8 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
         break;
 
     case EXIT_REASON_APIC_ACCESS:
-        if ( !vmx_handle_eoi_write() && !handle_mmio() )
-            hvm_inject_hw_exception(TRAP_gp_fault, 0);
+        if ( !vmx_handle_eoi_write() )
+            hvm_emulate(regs);
         break;
 
     case EXIT_REASON_EOI_INDUCED:
@@ -3026,11 +3026,7 @@ void vmx_vmexit_handler(struct cpu_user_regs *regs)
     case EXIT_REASON_IO_INSTRUCTION:
         __vmread(EXIT_QUALIFICATION, &exit_qualification);
         if ( exit_qualification & 0x10 )
-        {
-            /* INS, OUTS */
-            if ( !handle_mmio() )
-                hvm_inject_hw_exception(TRAP_gp_fault, 0);
-        }
+            hvm_emulate(regs);   /* INS, OUTS */
         else
         {
             /* IN, OUT */
diff --git a/xen/include/asm-x86/hvm/emulate.h b/xen/include/asm-x86/hvm/emulate.h
index 00a06cc..bc4a249 100644
--- a/xen/include/asm-x86/hvm/emulate.h
+++ b/xen/include/asm-x86/hvm/emulate.h
@@ -35,6 +35,7 @@ struct hvm_emulate_ctxt {
     uint32_t intr_shadow;
 };
 
+void hvm_emulate(struct cpu_user_regs *regs);
 int hvm_emulate_one(
     struct hvm_emulate_ctxt *hvmemul_ctxt);
 void hvm_emulate_prepare(
-- 
1.8.3.1