[Xen-devel] [PATCH v6 2/7] xen/x86: split Dom0 build into PV and PVHv2

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Split the Dom0 builder into two different functions, one for PV (and classic
PVH), and another one for PVHv2. Introduce a new command line parameter called
'dom0' that can be used to request the creation of a PVHv2 Dom0 by setting the
'hvm' sub-option. A panic has also been added if a user tries to use dom0=hvm
until all the code is in place, then the panic will be removed.

While there mark the dom0_shadow option that was used by PV Dom0 as deprecated,
it was lacking documentation and was not functional. Point users towards
dom0=shadow instead.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Changes since v5:
 - Remove duplicate define.
 - Also move the sanity check for d->vcpu[0]->is_initialised.
 - Mark dom0_shadow as deprecated, point users to switch to dom0=shadow.
 - Move the temporary panic from setup.c to the end of construct_dom0_pvh.

Changes since v4:
 - Move common sanity BUG_ONs and process_pending_softirqs to construct_dom0.
 - Remove the non-existant documentation about dom0_shadow option.
 - Fix the define of dom0_shadow to be 'false' instead of 0.
 - Move the parsing of the dom0 command line option to domain_build.c.
 - s/hvm/pvh.

Changes since v3:
 - Correctly declare the parameter list.
 - Add a panic if dom0=hvm is used. This will be removed once all the code is in
   place.

Changes since v2:
 - Fix coding style.
 - Introduce a new dom0 option that allows passing several parameters.
   Currently supported ones are hvm and shadow.

Changes since RFC:
 - Add documentation for the new command line option.
 - Simplify the logic in construct_dom0.
---
 docs/misc/xen-command-line.markdown | 19 ++++++++++
 xen/arch/x86/domain_build.c         | 71 +++++++++++++++++++++++++++++++------
 xen/arch/x86/setup.c                |  8 +++++
 xen/include/asm-x86/setup.h         |  7 ++++
 4 files changed, 94 insertions(+), 11 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index a11fdf9..3acbb33 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -649,6 +649,8 @@ affinities to prefer but be not limited to the specified 
node(s).
 ### dom0\_shadow
 > `= <boolean>`
 
+This option is deprecated, please use `dom0=shadow` instead.
+
 ### dom0\_vcpus\_pin
 > `= <boolean>`
 
@@ -656,6 +658,23 @@ affinities to prefer but be not limited to the specified 
node(s).
 
 Pin dom0 vcpus to their respective pcpus
 
+### dom0
+> `= List of [ pvh | shadow ]`
+
+> Sub-options:
+
+> `pvh`
+
+> Default: `false`
+
+Flag that makes a dom0 boot in PVHv2 mode.
+
+> `shadow`
+
+> Default: `false`
+
+Flag that makes a dom0 use shadow paging.
+
 ### dom0pvh
 > `= <boolean>`
 
diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index 243df96..7123931 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -191,11 +191,38 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
 }
 
 #ifdef CONFIG_SHADOW_PAGING
-static bool_t __initdata opt_dom0_shadow;
+bool __initdata opt_dom0_shadow;
 boolean_param("dom0_shadow", opt_dom0_shadow);
-#else
-#define opt_dom0_shadow 0
 #endif
+bool __initdata dom0_pvh;
+
+/*
+ * List of parameters that affect Dom0 creation:
+ *
+ *  - pvh               Create a PVHv2 Dom0.
+ *  - shadow            Use shadow paging for Dom0.
+ */
+static void __init parse_dom0_param(char *s)
+{
+    char *ss;
+
+    do {
+
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        if ( !strcmp(s, "pvh") )
+            dom0_pvh = true;
+#ifdef CONFIG_SHADOW_PAGING
+        else if ( !strcmp(s, "shadow") )
+            opt_dom0_shadow = true;
+#endif
+
+        s = ss + 1;
+    } while ( ss );
+}
+custom_param("dom0", parse_dom0_param);
 
 static char __initdata opt_dom0_ioports_disable[200] = "";
 string_param("dom0_ioports_disable", opt_dom0_ioports_disable);
@@ -951,7 +978,7 @@ static int __init setup_permissions(struct domain *d)
     return rc;
 }
 
-int __init construct_dom0(
+static int __init construct_dom0_pv(
     struct domain *d,
     const module_t *image, unsigned long image_headroom,
     module_t *initrd,
@@ -1007,13 +1034,6 @@ int __init construct_dom0(
     /* Machine address of next candidate page-table page. */
     paddr_t mpt_alloc;
 
-    /* Sanity! */
-    BUG_ON(d->domain_id != 0);
-    BUG_ON(d->vcpu[0] == NULL);
-    BUG_ON(v->is_initialised);
-
-    process_pending_softirqs();
-
     printk("*** LOADING DOMAIN 0 ***\n");
 
     d->max_pages = ~0U;
@@ -1655,6 +1675,35 @@ out:
     return rc;
 }
 
+static int __init construct_dom0_pvh(struct domain *d, const module_t *image,
+                                     unsigned long image_headroom,
+                                     module_t *initrd,
+                                     void *(*bootstrap_map)(const module_t *),
+                                     char *cmdline)
+{
+
+    printk("** Building a PVH Dom0 **\n");
+
+    panic("Building a PVHv2 Dom0 is not yet supported.");
+    return 0;
+}
+
+int __init construct_dom0(struct domain *d, const module_t *image,
+                          unsigned long image_headroom, module_t *initrd,
+                          void *(*bootstrap_map)(const module_t *),
+                          char *cmdline)
+{
+    /* Sanity! */
+    BUG_ON(d->domain_id != 0);
+    BUG_ON(d->vcpu[0] == NULL);
+    BUG_ON(d->vcpu[0]->is_initialised);
+
+    process_pending_softirqs();
+
+    return (is_hvm_domain(d) ? construct_dom0_pvh : construct_dom0_pv)
+           (d, image, image_headroom, initrd,bootstrap_map, cmdline);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 176ee74..48fd955 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1550,6 +1550,14 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     if ( opt_dom0pvh )
         domcr_flags |= DOMCRF_pvh | DOMCRF_hap;
 
+    if ( dom0_pvh )
+    {
+        domcr_flags |= DOMCRF_hvm |
+                       ((hvm_funcs.hap_supported && !opt_dom0_shadow) ?
+                         DOMCRF_hap : 0);
+        config.emulation_flags = XEN_X86_EMU_LAPIC|XEN_X86_EMU_IOAPIC;
+    }
+
     /* Create initial domain 0. */
     dom0 = domain_create(0, domcr_flags, 0, &config);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
index c65b79c..47b9442 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -57,4 +57,11 @@ extern uint8_t kbd_shift_flags;
 extern unsigned long highmem_start;
 #endif
 
+#ifdef CONFIG_SHADOW_PAGING
+extern bool opt_dom0_shadow;
+#else
+#define opt_dom0_shadow false
+#endif
+extern bool dom0_pvh;
+
 #endif
-- 
2.10.1 (Apple Git-78)


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