libxc: introduce xc_domain_get_guest_width()

As a wrapper to XEN_DOMCTL_get_address_size, and use it
wherever the call was being issued directly via do_domctl(),
saving quite some line of code.

Actually, the function returns the guest width in bytes,
rather than directly what XEN_DOMCTL_get_address_size provides
(which is a number of bits), since that is what it is useful
almost everywhere.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

10 files changed, 48 insertions, 78 deletions

diff --git a/tools/libxc/xc_core.c b/tools/libxc/xc_core.c
index 4207eed6dc..4bc1abb441 100644
--- a/tools/libxc/xc_core.c
+++ b/tools/libxc/xc_core.c
@@ -417,24 +417,6 @@ elfnote_dump_format_version(xc_interface *xch,
     return dump_rtn(xch, args, (char*)&format_version, sizeof(format_version));
 }
 
-static int
-get_guest_width(xc_interface *xch,
-                uint32_t domid,
-                unsigned int *guest_width)
-{
-    DECLARE_DOMCTL;
-
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-
-    if ( do_domctl(xch, &domctl) != 0 )
-        return 1;
-        
-    *guest_width = domctl.u.address_size.size / 8;
-    return 0;
-}
-
 int
 xc_domain_dumpcore_via_callback(xc_interface *xch,
                                 uint32_t domid,
@@ -478,7 +460,7 @@ xc_domain_dumpcore_via_callback(xc_interface *xch,
     struct xc_core_section_headers *sheaders = NULL;
     Elf64_Shdr *shdr;
  
-    if ( get_guest_width(xch, domid, &dinfo->guest_width) != 0 )
+    if ( xc_domain_get_guest_width(xch, domid, &dinfo->guest_width) != 0 )
     {
         PERROR("Could not get address size for domain");
         return sts;
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index fa47787d3e..bbbf9b80eb 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -436,17 +436,15 @@ static void xc_cpuid_pv_policy(
     const unsigned int *input, unsigned int *regs)
 {
     DECLARE_DOMCTL;
+    unsigned int guest_width;
     int guest_64bit, xen_64bit = hypervisor_is_64bit(xch);
     char brand[13];
     uint64_t xfeature_mask;
 
     xc_cpuid_brand_get(brand);
 
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-    do_domctl(xch, &domctl);
-    guest_64bit = (domctl.u.address_size.size == 64);
+    xc_domain_get_guest_width(xch, domid, &guest_width);
+    guest_64bit = (guest_width == 8);
 
     /* Detecting Xen's atitude towards XSAVE */
     memset(&domctl, 0, sizeof(domctl));
diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index 41f59d3dd1..7cc2ff2411 100644
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -54,24 +54,17 @@ const char *xc_domain_get_native_protocol(xc_interface *xch,
     int ret;
     uint32_t guest_width;
     const char *protocol;
-    DECLARE_DOMCTL;
 
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-
-    ret = do_domctl(xch, &domctl);
+    ret = xc_domain_get_guest_width(xch, domid, &guest_width);
 
     if ( ret )
         return NULL;
 
-    guest_width = domctl.u.address_size.size;
-
     switch (guest_width) {
-    case 32: /* 32 bit guest */
+    case 4: /* 32 bit guest */
         protocol = XEN_IO_PROTO_ABI_X86_32;
         break;
-    case 64: /* 64 bit guest */
+    case 8: /* 64 bit guest */
         protocol = XEN_IO_PROTO_ABI_X86_64;
         break;
     default:
diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 3257e2af94..c0ce079e3d 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -270,6 +270,22 @@ out:
     return ret;
 }
 
+int xc_domain_get_guest_width(xc_interface *xch, uint32_t domid,
+                              unsigned int *guest_width)
+{
+    DECLARE_DOMCTL;
+
+    memset(&domctl, 0, sizeof(domctl));
+    domctl.domain = domid;
+    domctl.cmd = XEN_DOMCTL_get_address_size;
+
+    if ( do_domctl(xch, &domctl) != 0 )
+        return 1;
+
+    /* We want the result in bytes */
+    *guest_width = domctl.u.address_size.size / 8;
+    return 0;
+}
 
 int xc_domain_getinfo(xc_interface *xch,
                       uint32_t first_domid,
diff --git a/tools/libxc/xc_offline_page.c b/tools/libxc/xc_offline_page.c
index 36b981285c..1f6dbc6d5e 100644
--- a/tools/libxc/xc_offline_page.c
+++ b/tools/libxc/xc_offline_page.c
@@ -193,21 +193,14 @@ static int get_pt_level(xc_interface *xch, uint32_t domid,
                         unsigned int *pt_level,
                         unsigned int *gwidth)
 {
-    DECLARE_DOMCTL;
     xen_capabilities_info_t xen_caps = "";
 
     if (xc_version(xch, XENVER_capabilities, &xen_caps) != 0)
         return -1;
 
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-
-    if ( do_domctl(xch, &domctl) != 0 )
+    if (xc_domain_get_guest_width(xch, domid, gwidth) != 0)
         return -1;
 
-    *gwidth = domctl.u.address_size.size / 8;
-
     if (strstr(xen_caps, "xen-3.0-x86_64"))
         /* Depends on whether it's a compat 32-on-64 guest */
         *pt_level = ( (*gwidth == 8) ? 4 : 3 );
diff --git a/tools/libxc/xc_pagetab.c b/tools/libxc/xc_pagetab.c
index 27c4e9fcbc..8525967527 100644
--- a/tools/libxc/xc_pagetab.c
+++ b/tools/libxc/xc_pagetab.c
@@ -51,15 +51,13 @@ unsigned long xc_translate_foreign_address(xc_interface *xch, uint32_t dom,
         pt_levels = (ctx.msr_efer&EFER_LMA) ? 4 : (ctx.cr4&CR4_PAE) ? 3 : 2;
         paddr = ctx.cr3 & ((pt_levels == 3) ? ~0x1full : ~0xfffull);
     } else {
-        DECLARE_DOMCTL;
+        unsigned int gwidth;
         vcpu_guest_context_any_t ctx;
         if (xc_vcpu_getcontext(xch, dom, vcpu, &ctx) != 0)
             return 0;
-        domctl.domain = dom;
-        domctl.cmd = XEN_DOMCTL_get_address_size;
-        if ( do_domctl(xch, &domctl) != 0 )
+        if (xc_domain_get_guest_width(xch, dom, &gwidth) != 0)
             return 0;
-        if (domctl.u.address_size.size == 64) {
+        if (gwidth == 8) {
             pt_levels = 4;
             paddr = (uint64_t)xen_cr3_to_pfn_x86_64(ctx.x64.ctrlreg[3])
                 << PAGE_SHIFT;
diff --git a/tools/libxc/xc_resume.c b/tools/libxc/xc_resume.c
index 1c43ec612d..cb6165049f 100644
--- a/tools/libxc/xc_resume.c
+++ b/tools/libxc/xc_resume.c
@@ -24,19 +24,6 @@
 #include <xen/foreign/x86_64.h>
 #include <xen/hvm/params.h>
 
-static int pv_guest_width(xc_interface *xch, uint32_t domid)
-{
-    DECLARE_DOMCTL;
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-    if ( xc_domctl(xch, &domctl) != 0 )
-    {
-        PERROR("Could not get guest address size");
-        return -1;
-    }
-    return domctl.u.address_size.size / 8;
-}
-
 static int modify_returncode(xc_interface *xch, uint32_t domid)
 {
     vcpu_guest_context_any_t ctxt;
@@ -71,8 +58,7 @@ static int modify_returncode(xc_interface *xch, uint32_t domid)
     else
     {
         /* Probe PV guest address width. */
-        dinfo->guest_width = pv_guest_width(xch, domid);
-        if ( dinfo->guest_width < 0 )
+        if ( xc_domain_get_guest_width(xch, domid, &dinfo->guest_width) )
             return -1;
     }
 
@@ -120,7 +106,8 @@ static int xc_domain_resume_any(xc_interface *xch, uint32_t domid)
     xc_dominfo_t info;
     int i, rc = -1;
 #if defined(__i386__) || defined(__x86_64__)
-    struct domain_info_context _dinfo = { .p2m_size = 0 };
+    struct domain_info_context _dinfo = { .guest_width = 0,
+                                          .p2m_size = 0 };
     struct domain_info_context *dinfo = &_dinfo;
     unsigned long mfn;
     vcpu_guest_context_any_t ctxt;
@@ -147,7 +134,7 @@ static int xc_domain_resume_any(xc_interface *xch, uint32_t domid)
         return rc;
     }
 
-    dinfo->guest_width = pv_guest_width(xch, domid);
+    xc_domain_get_guest_width(xch, domid, &dinfo->guest_width);
     if ( dinfo->guest_width != sizeof(long) )
     {
         ERROR("Cannot resume uncooperative cross-address-size guests");
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index f2cebafc9d..58d51f353a 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -560,6 +560,19 @@ int xc_vcpu_getaffinity(xc_interface *xch,
                         int vcpu,
                         xc_cpumap_t cpumap);
 
+
+/**
+ * This function will return the guest_width (in bytes) for the
+ * specified domain.
+ *
+ * @param xch a handle to an open hypervisor interface.
+ * @param domid the domain id one wants the address size width of.
+ * @param addr_size the address size.
+ */
+int xc_domain_get_guest_width(xc_interface *xch, uint32_t domid,
+                              unsigned int *guest_width);
+
+
 /**
  * This function will return information about one or more domains. It is
  * designed to iterate over the list of domains. If a single domain is
diff --git a/tools/libxc/xg_save_restore.h b/tools/libxc/xg_save_restore.h
index 651200339b..f859621f62 100644
--- a/tools/libxc/xg_save_restore.h
+++ b/tools/libxc/xg_save_restore.h
@@ -301,7 +301,6 @@ static inline int get_platform_info(xc_interface *xch, uint32_t dom,
 {
     xen_capabilities_info_t xen_caps = "";
     xen_platform_parameters_t xen_params;
-    DECLARE_DOMCTL;
 
     if (xc_version(xch, XENVER_platform_parameters, &xen_params) != 0)
         return 0;
@@ -313,15 +312,9 @@ static inline int get_platform_info(xc_interface *xch, uint32_t dom,
 
     *hvirt_start = xen_params.virt_start;
 
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = dom;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-
-    if ( do_domctl(xch, &domctl) != 0 )
+    if ( xc_domain_get_guest_width(xch, dom, guest_width) != 0)
         return 0; 
 
-    *guest_width = domctl.u.address_size.size / 8;
-
     /* 64-bit tools will see the 64-bit hvirt_start, but 32-bit guests 
      * will be using the compat one. */
     if ( *guest_width < sizeof (unsigned long) )
diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c
index 060e480005..1214185bd8 100644
--- a/tools/xentrace/xenctx.c
+++ b/tools/xentrace/xenctx.c
@@ -771,12 +771,9 @@ static void dump_ctx(int vcpu)
             }
             ctxt_word_size = (strstr(xen_caps, "xen-3.0-x86_64")) ? 8 : 4;
         } else {
-            struct xen_domctl domctl;
-            memset(&domctl, 0, sizeof domctl);
-            domctl.domain = xenctx.domid;
-            domctl.cmd = XEN_DOMCTL_get_address_size;
-            if (xc_domctl(xenctx.xc_handle, &domctl) == 0)
-                ctxt_word_size = guest_word_size = domctl.u.address_size.size / 8;
+            unsigned int gw;
+            if ( !xc_domain_get_guest_width(xenctx.xc_handle, xenctx.domid, &gw) )
+                ctxt_word_size = guest_word_size = gw;
         }
     }
 #endif