[RFC PATCH 1/15]: PVH xen: turn gdb_frames/gdt_ents into union

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

PVH only needs gdtaddr and gdtsz, so a union is created. There is no
functional code change in this patch.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>


diff -r bf249cd5f2c1 -r 278d7a933d88 tools/libxc/xc_domain_restore.c
--- a/tools/libxc/xc_domain_restore.c	Tue Oct 30 18:12:11 2012 +0000
+++ b/tools/libxc/xc_domain_restore.c	Fri Jan 11 16:19:40 2013 -0800
@@ -1933,15 +1933,15 @@ int xc_domain_restore(xc_interface *xch,
             munmap(start_info, PAGE_SIZE);
         }
         /* Uncanonicalise each GDT frame number. */
-        if ( GET_FIELD(ctxt, gdt_ents) > 8192 )
+        if ( GET_FIELD(ctxt, u.pv.gdt_ents) > 8192 )
         {
             ERROR("GDT entry count out of range");
             goto out;
         }
 
-        for ( j = 0; (512*j) < GET_FIELD(ctxt, gdt_ents); j++ )
+        for ( j = 0; (512*j) < GET_FIELD(ctxt, u.pv.gdt_ents); j++ )
         {
-            pfn = GET_FIELD(ctxt, gdt_frames[j]);
+            pfn = GET_FIELD(ctxt, u.pv.gdt_frames[j]);
             if ( (pfn >= dinfo->p2m_size) ||
                  (pfn_type[pfn] != XEN_DOMCTL_PFINFO_NOTAB) )
             {
@@ -1949,7 +1949,7 @@ int xc_domain_restore(xc_interface *xch,
                       j, (unsigned long)pfn);
                 goto out;
             }
-            SET_FIELD(ctxt, gdt_frames[j], ctx->p2m[pfn]);
+            SET_FIELD(ctxt, u.pv.gdt_frames[j], ctx->p2m[pfn]);
         }
         /* Uncanonicalise the page table base pointer. */
         pfn = UNFOLD_CR3(GET_FIELD(ctxt, ctrlreg[3]));
diff -r bf249cd5f2c1 -r 278d7a933d88 tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c	Tue Oct 30 18:12:11 2012 +0000
+++ b/tools/libxc/xc_domain_save.c	Fri Jan 11 16:19:40 2013 -0800
@@ -1889,15 +1889,15 @@ int xc_domain_save(xc_interface *xch, in
         }
 
         /* Canonicalise each GDT frame number. */
-        for ( j = 0; (512*j) < GET_FIELD(&ctxt, gdt_ents); j++ )
+        for ( j = 0; (512*j) < GET_FIELD(&ctxt, u.pv.gdt_ents); j++ )
         {
-            mfn = GET_FIELD(&ctxt, gdt_frames[j]);
+            mfn = GET_FIELD(&ctxt, u.pv.gdt_frames[j]);
             if ( !MFN_IS_IN_PSEUDOPHYS_MAP(mfn) )
             {
                 ERROR("GDT frame is not in range of pseudophys map");
                 goto out;
             }
-            SET_FIELD(&ctxt, gdt_frames[j], mfn_to_pfn(mfn));
+            SET_FIELD(&ctxt, u.pv.gdt_frames[j], mfn_to_pfn(mfn));
         }
 
         /* Canonicalise the page table base pointer. */
diff -r bf249cd5f2c1 -r 278d7a933d88 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c	Tue Oct 30 18:12:11 2012 +0000
+++ b/xen/arch/x86/domain.c	Fri Jan 11 16:19:40 2013 -0800
@@ -811,8 +811,8 @@ int arch_set_info_guest(
         }
 
         for ( i = 0; i < ARRAY_SIZE(v->arch.pv_vcpu.gdt_frames); ++i )
-            fail |= v->arch.pv_vcpu.gdt_frames[i] != c(gdt_frames[i]);
-        fail |= v->arch.pv_vcpu.gdt_ents != c(gdt_ents);
+            fail |= v->arch.pv_vcpu.gdt_frames[i] != c(u.pv.gdt_frames[i]);
+        fail |= v->arch.pv_vcpu.gdt_ents != c(u.pv.gdt_ents);
 
         fail |= v->arch.pv_vcpu.ldt_base != c(ldt_base);
         fail |= v->arch.pv_vcpu.ldt_ents != c(ldt_ents);
@@ -861,17 +861,17 @@ int arch_set_info_guest(
         d->vm_assist = c(vm_assist);
 
     if ( !compat )
-        rc = (int)set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
+        rc = (int)set_gdt(v, c.nat->u.pv.gdt_frames, c.nat->u.pv.gdt_ents);
     else
     {
         unsigned long gdt_frames[ARRAY_SIZE(v->arch.pv_vcpu.gdt_frames)];
-        unsigned int n = (c.cmp->gdt_ents + 511) / 512;
+        unsigned int n = (c.cmp->u.pv.gdt_ents + 511) / 512;
 
         if ( n > ARRAY_SIZE(v->arch.pv_vcpu.gdt_frames) )
             return -EINVAL;
         for ( i = 0; i < n; ++i )
-            gdt_frames[i] = c.cmp->gdt_frames[i];
-        rc = (int)set_gdt(v, gdt_frames, c.cmp->gdt_ents);
+            gdt_frames[i] = c.cmp->u.pv.gdt_frames[i];
+        rc = (int)set_gdt(v, gdt_frames, c.cmp->u.pv.gdt_ents);
     }
     if ( rc != 0 )
         return rc;
diff -r bf249cd5f2c1 -r 278d7a933d88 xen/arch/x86/domctl.c
--- a/xen/arch/x86/domctl.c	Tue Oct 30 18:12:11 2012 +0000
+++ b/xen/arch/x86/domctl.c	Fri Jan 11 16:19:40 2013 -0800
@@ -1651,12 +1651,12 @@ void arch_get_info_guest(struct vcpu *v,
         c(ldt_base = v->arch.pv_vcpu.ldt_base);
         c(ldt_ents = v->arch.pv_vcpu.ldt_ents);
         for ( i = 0; i < ARRAY_SIZE(v->arch.pv_vcpu.gdt_frames); ++i )
-            c(gdt_frames[i] = v->arch.pv_vcpu.gdt_frames[i]);
-        BUILD_BUG_ON(ARRAY_SIZE(c.nat->gdt_frames) !=
-                     ARRAY_SIZE(c.cmp->gdt_frames));
-        for ( ; i < ARRAY_SIZE(c.nat->gdt_frames); ++i )
-            c(gdt_frames[i] = 0);
-        c(gdt_ents = v->arch.pv_vcpu.gdt_ents);
+            c(u.pv.gdt_frames[i] = v->arch.pv_vcpu.gdt_frames[i]);
+        BUILD_BUG_ON(ARRAY_SIZE(c.nat->u.pv.gdt_frames) !=
+                     ARRAY_SIZE(c.cmp->u.pv.gdt_frames));
+        for ( ; i < ARRAY_SIZE(c.nat->u.pv.gdt_frames); ++i )
+            c(u.pv.gdt_frames[i] = 0);
+        c(u.pv.gdt_ents = v->arch.pv_vcpu.gdt_ents);
         c(kernel_ss = v->arch.pv_vcpu.kernel_ss);
         c(kernel_sp = v->arch.pv_vcpu.kernel_sp);
         for ( i = 0; i < ARRAY_SIZE(v->arch.pv_vcpu.ctrlreg); ++i )
diff -r bf249cd5f2c1 -r 278d7a933d88 xen/include/public/arch-x86/xen.h
--- a/xen/include/public/arch-x86/xen.h	Tue Oct 30 18:12:11 2012 +0000
+++ b/xen/include/public/arch-x86/xen.h	Fri Jan 11 16:19:40 2013 -0800
@@ -157,7 +157,16 @@ struct vcpu_guest_context {
     struct cpu_user_regs user_regs;         /* User-level CPU registers     */
     struct trap_info trap_ctxt[256];        /* Virtual IDT                  */
     unsigned long ldt_base, ldt_ents;       /* LDT (linear address, # ents) */
-    unsigned long gdt_frames[16], gdt_ents; /* GDT (machine frames, # ents) */
+    union {
+        struct {
+            /* GDT (machine frames, # ents) */
+            unsigned long gdt_frames[16], gdt_ents;
+        } pv;
+        struct {
+            /* PVH: GDTR addr and size */   
+            unsigned long gdtaddr, gdtsz;
+        } pvh;
+    } u;
     unsigned long kernel_ss, kernel_sp;     /* Virtual TSS (only SS1/SP1)   */
     /* NB. User pagetable on x86/64 is placed in ctrlreg[1]. */
     unsigned long ctrlreg[8];               /* CR0-CR7 (control registers)  */