[PATCH v2 1/6] xen: introduce hardware domain create flag

[Jason Andryuk <jason.andryuk@xxxxxxx>]

From: "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>

Add and use a new internal create domain flag to specify the hardware
domain.  This removes the hardcoding of domid 0 as the hardware domain.

This allows more flexibility with domain creation.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
---
v2:
() around binary &
Only allow late_hwdom for dom0
---
 xen/arch/arm/domain_build.c | 2 +-
 xen/arch/x86/setup.c        | 3 ++-
 xen/common/domain.c         | 6 +++++-
 xen/include/xen/domain.h    | 2 ++
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 2b5b433183..051c48329a 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2366,7 +2366,7 @@ void __init create_dom0(void)
         .max_maptrack_frames = -1,
         .grant_opts = XEN_DOMCTL_GRANT_version(opt_gnttab_max_version),
     };
-    unsigned int flags = CDF_privileged;
+    unsigned int flags = CDF_privileged | CDF_hardware;
     int rc;
 
     /* The vGIC for DOM0 is exactly emulating the hardware GIC */
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index d70abb7e0c..67d399c469 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1018,7 +1018,8 @@ static struct domain *__init create_dom0(struct boot_info 
*bi)
 
     /* Create initial domain.  Not d0 for pvshim. */
     domid = get_initial_domain_id();
-    d = domain_create(domid, &dom0_cfg, pv_shim ? 0 : CDF_privileged);
+    d = domain_create(domid, &dom0_cfg,
+                      pv_shim ? 0 : CDF_privileged | CDF_hardware);
     if ( IS_ERR(d) )
         panic("Error creating d%u: %ld\n", domid, PTR_ERR(d));
 
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 585fd726a9..b3eb589872 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -820,11 +820,15 @@ struct domain *domain_create(domid_t domid,
     d->is_privileged = flags & CDF_privileged;
 
     /* Sort out our idea of is_hardware_domain(). */
-    if ( domid == 0 || domid == hardware_domid )
+    if ( (flags & CDF_hardware) || domid == hardware_domid )
     {
         if ( hardware_domid < 0 || hardware_domid >= DOMID_FIRST_RESERVED )
             panic("The value of hardware_dom must be a valid domain ID\n");
 
+        /* late_hwdom is only allowed for dom0. */
+        if ( hardware_domain && hardware_domain->domain_id )
+            return ERR_PTR(-EINVAL);
+
         old_hwdom = hardware_domain;
         hardware_domain = d;
     }
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 83069de501..9be18d16b9 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -52,6 +52,8 @@ domid_t get_initial_domain_id(void);
 #else
 #define CDF_staticmem            0
 #endif
+/* This is the hardware domain.  Only 1 allowed. */
+#define CDF_hardware             (1U << 3)
 
 #define is_domain_direct_mapped(d) ((d)->cdf & CDF_directmap)
 #define is_domain_using_staticmem(d) ((d)->cdf & CDF_staticmem)
-- 
2.49.0