[Xen-devel] [PATCH v4 09/14] 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.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
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 | 17 +++++++++++++++++
 xen/arch/x86/domain_build.c         | 28 +++++++++++++++++++++++----
 xen/arch/x86/setup.c                | 38 +++++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/setup.h         |  6 ++++++
 4 files changed, 85 insertions(+), 4 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index 0138978..c9729be 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -656,6 +656,23 @@ affinities to prefer but be not limited to the specified 
node(s).
 
 Pin dom0 vcpus to their respective pcpus
 
+### dom0
+> `= List of [ hvm | shadow ]`
+
+> Sub-options:
+
+> `hvm`
+
+> 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 1e557b9..2c9ebf2 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -191,10 +191,8 @@ 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
 
 static char __initdata opt_dom0_ioports_disable[200] = "";
@@ -951,7 +949,7 @@ 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,
@@ -1655,6 +1653,28 @@ out:
     return rc;
 }
 
+static int __init construct_dom0_hvm(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");
+
+    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)
+{
+
+    return (is_hvm_domain(d) ? construct_dom0_hvm : 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 b130671..255e20c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -187,6 +187,35 @@ static void __init parse_acpi_param(char *s)
     }
 }
 
+/*
+ * List of parameters that affect Dom0 creation:
+ *
+ *  - hvm               Create a PVHv2 Dom0.
+ *  - shadow            Use shadow paging for Dom0.
+ */
+static bool __initdata dom0_hvm;
+static void __init parse_dom0_param(char *s)
+{
+    char *ss;
+
+    do {
+
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        if ( !strcmp(s, "hvm") )
+            dom0_hvm = 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 const module_t *__initdata initial_images;
 static unsigned int __initdata nr_initial_images;
 
@@ -1541,6 +1570,15 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     if ( opt_dom0pvh )
         domcr_flags |= DOMCRF_pvh | DOMCRF_hap;
 
+    if ( dom0_hvm )
+    {
+        panic("Building a PVHv2 Dom0 is not yet supported.");
+        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..c4179d1 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -57,4 +57,10 @@ 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 0
+#endif
+
 #endif
-- 
2.9.3 (Apple Git-75)


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