tools/dombuilder: Remove clear_page() from xc_dom_boot.c

pfn 0 is a legitimate (albeit unlikely) frame to use, so skipping it is wrong.
This behaviour appears to exists simply to cover the fact that zero is the
default value of an uninitialised field in dom.

ARM already clears the frames at the point that the pfns are allocated,
meaning that the added clear_page() is wasteful.  Alter x86 to match ARM and
clear the page when it is allocated.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Julien Grall <julien.grall@arm.com>
Release-acked-by: Julien Grall <julien.grall@linaro.org>

diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 7c4997a7e8e8057bd7cc9a35a8401eb3c0348306..fce151d821655724be82eb362e45ac6e66847c2d 100644 (file)
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -91,7 +91,8 @@ static int alloc_magic_pages(struct xc_dom_image *dom)
     xc_clear_domain_page(dom->xch, dom->guest_domid, dom->console_pfn);
     xc_clear_domain_page(dom->xch, dom->guest_domid, dom->xenstore_pfn);
     xc_clear_domain_page(dom->xch, dom->guest_domid, base + MEMACCESS_PFN_OFFSET);
-    xc_clear_domain_page(dom->xch, dom->guest_domid, base + VUART_PFN_OFFSET);
+    xc_clear_domain_page(dom->xch, dom->guest_domid, dom->vuart_gfn);
+
     xc_hvm_param_set(dom->xch, dom->guest_domid, HVM_PARAM_CONSOLE_PFN,
             dom->console_pfn);
     xc_hvm_param_set(dom->xch, dom->guest_domid, HVM_PARAM_STORE_PFN,

diff --git a/tools/libxc/xc_dom_boot.c b/tools/libxc/xc_dom_boot.c
index 40eb5185a953ed6d8ef84375988799b8e78a0c8d..2e5681dc5d97db7448b98a7ab751d12369eb221c 100644 (file)
--- a/tools/libxc/xc_dom_boot.c
+++ b/tools/libxc/xc_dom_boot.c
@@ -62,25 +62,6 @@ static int setup_hypercall_page(struct xc_dom_image *dom)
     return rc;
 }
 
-static int clear_page(struct xc_dom_image *dom, xen_pfn_t pfn)
-{
-    xen_pfn_t dst;
-    int rc;
-
-    if ( pfn == 0 )
-        return 0;
-
-    dst = xc_dom_p2m(dom, pfn);
-    DOMPRINTF("%s: pfn 0x%" PRIpfn ", mfn 0x%" PRIpfn "",
-              __FUNCTION__, pfn, dst);
-    rc = xc_clear_domain_page(dom->xch, dom->guest_domid, dst);
-    if ( rc != 0 )
-        xc_dom_panic(dom->xch, XC_INTERNAL_ERROR,
-                     "%s: xc_clear_domain_page failed (pfn 0x%" PRIpfn
-                     ", rc=%d)", __FUNCTION__, pfn, rc);
-    return rc;
-}
-
 
 /* ------------------------------------------------------------------------ */
 
@@ -222,13 +203,6 @@ int xc_dom_boot_image(struct xc_dom_image *dom)
         if ( (rc = dom->arch_hooks->setup_pgtables(dom)) != 0 )
             return rc;
 
-    if ( (rc = clear_page(dom, dom->console_pfn)) != 0 )
-        return rc;
-    if ( (rc = clear_page(dom, dom->xenstore_pfn)) != 0 )
-        return rc;
-    if ( (rc = clear_page(dom, dom->vuart_gfn)) != 0 )
-        return rc;
-
     /* start info page */
     if ( dom->arch_hooks->start_info )
         dom->arch_hooks->start_info(dom);

diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index 47db218ef3448db92e2e7905c6c61c3a32eebafc..bff68a011f154bc16cafdda9c18b1f666b3d37db 100644 (file)
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -543,10 +543,14 @@ static int alloc_magic_pages_pv(struct xc_dom_image *dom)
     dom->xenstore_pfn = xc_dom_alloc_page(dom, "xenstore");
     if ( dom->xenstore_pfn == INVALID_PFN )
         return -1;
+    xc_clear_domain_page(dom->xch, dom->guest_domid,
+                         xc_dom_p2m(dom, dom->xenstore_pfn));
 
     dom->console_pfn = xc_dom_alloc_page(dom, "console");
     if ( dom->console_pfn == INVALID_PFN )
         return -1;
+    xc_clear_domain_page(dom->xch, dom->guest_domid,
+                         xc_dom_p2m(dom, dom->console_pfn));
 
     dom->alloc_bootstack = 1;
 
@@ -696,7 +700,11 @@ static int alloc_magic_pages_hvm(struct xc_dom_image *dom)
                      special_pfn(SPECIALPAGE_IDENT_PT) << PAGE_SHIFT);
 
     dom->console_pfn = special_pfn(SPECIALPAGE_CONSOLE);
+    xc_clear_domain_page(dom->xch, dom->guest_domid, dom->console_pfn);
+
     dom->xenstore_pfn = special_pfn(SPECIALPAGE_XENSTORE);
+    xc_clear_domain_page(dom->xch, dom->guest_domid, dom->xenstore_pfn);
+
     dom->parms.virt_hypercall = -1;
 
     rc = 0;