[Xen-devel] [PATCH v2 08/23] vixen: allow dom0 to be created with a domid != 0

[Anthony Liguori <aliguori@xxxxxxxx>]

From: Anthony Liguori <aliguori@xxxxxxxxxx>

Some older guests special case domid=0 instead of checking the
shared info flags so in order to get PV drivers loaded properly,
we need to make the guest always appear with a domid != 0.

While the Vixen domain is the hardware domain, we don't want it
to behave that way so we also modify the is_hardware_domain()
check.

Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
---
v1 -> v2
 - allow vixen domain id to be overridden via the Xen command line
---
 xen/arch/x86/dom0_build.c         | 2 +-
 xen/arch/x86/guest/vixen.c        | 7 +++++++
 xen/arch/x86/setup.c              | 2 +-
 xen/common/domain.c               | 4 ++--
 xen/include/asm-arm/guest/vixen.h | 5 +++++
 xen/include/asm-x86/guest/vixen.h | 2 ++
 xen/include/xen/sched.h           | 6 +++++-
 7 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index bf992fe..88810db 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -469,7 +469,7 @@ int __init construct_dom0(struct domain *d, const module_t 
*image,
     int rc;
 
     /* Sanity! */
-    BUG_ON(d->domain_id != 0);
+    BUG_ON(d->domain_id != dom0_domid);
     BUG_ON(d->vcpu[0] == NULL);
     BUG_ON(d->vcpu[0]->is_initialised);
 
diff --git a/xen/arch/x86/guest/vixen.c b/xen/arch/x86/guest/vixen.c
index d82e68f..c0a81dd 100644
--- a/xen/arch/x86/guest/vixen.c
+++ b/xen/arch/x86/guest/vixen.c
@@ -22,9 +22,16 @@
 #include <asm/guest/vixen.h>
 
 static int in_vixen;
+static int vixen_domid = 1;
+
+integer_param("vixen_domid", vixen_domid);
 
 bool is_vixen(void)
 {
     return in_vixen > 0;
 }
 
+int vixen_get_domid(void)
+{
+    return vixen_domid;
+}
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 7627c3f..f9d087e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1591,7 +1591,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     }
 
     /* Create initial domain 0. */
-    dom0 = domain_create(0, domcr_flags, 0, &config);
+    dom0 = domain_create(dom0_domid, domcr_flags, 0, &config);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
         panic("Error creating domain 0");
 
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 7af8d12..b4d679e 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -202,7 +202,7 @@ static int late_hwdom_init(struct domain *d)
     struct domain *dom0;
     int rv;
 
-    if ( d != hardware_domain || d->domain_id == 0 )
+    if ( d != hardware_domain || d->domain_id == dom0_domid )
         return 0;
 
     rv = xsm_init_hardware_domain(XSM_HOOK, d);
@@ -310,7 +310,7 @@ struct domain *domain_create(domid_t domid, unsigned int 
domcr_flags,
     else
         d->guest_type = guest_type_pv;
 
-    if ( domid == 0 || domid == hardware_domid )
+    if ( domid == dom0_domid || domid == hardware_domid )
     {
         if ( hardware_domid < 0 || hardware_domid >= DOMID_FIRST_RESERVED )
             panic("The value of hardware_dom must be a valid domain ID");
diff --git a/xen/include/asm-arm/guest/vixen.h 
b/xen/include/asm-arm/guest/vixen.h
index ade6724..cb51698 100644
--- a/xen/include/asm-arm/guest/vixen.h
+++ b/xen/include/asm-arm/guest/vixen.h
@@ -78,4 +78,9 @@ static inline bool vixen_ring_process(uint16_t port)
     return false;
 }
 
+static inline int vixen_get_domid(void)
+{
+    return 0;
+}
+
 #endif
diff --git a/xen/include/asm-x86/guest/vixen.h 
b/xen/include/asm-x86/guest/vixen.h
index be90c46..4e80b76 100644
--- a/xen/include/asm-x86/guest/vixen.h
+++ b/xen/include/asm-x86/guest/vixen.h
@@ -70,4 +70,6 @@ HYPERVISOR_vcpu_op(int cmd, int vcpuid, void *extra_args)
 
 bool is_vixen(void);
 
+int vixen_get_domid(void);
+
 #endif
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 002ba29..5ddf6a2 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -27,6 +27,8 @@
 #include <public/vcpu.h>
 #include <public/vm_event.h>
 #include <public/event_channel.h>
+#include <asm/guest.h>
+#include <asm/guest/vixen.h>
 
 #ifdef CONFIG_COMPAT
 #include <compat/vcpu.h>
@@ -54,6 +56,8 @@ extern domid_t hardware_domid;
 #define hardware_domid 0
 #endif
 
+#define dom0_domid (is_vixen() ? vixen_get_domid() : 0)
+
 #ifndef CONFIG_COMPAT
 #define BITS_PER_EVTCHN_WORD(d) BITS_PER_XEN_ULONG
 #else
@@ -873,7 +877,7 @@ void watchdog_domain_destroy(struct domain *d);
  *    (that is, this would not be suitable for a driver domain)
  *  - There is never a reason to deny the hardware domain access to this
  */
-#define is_hardware_domain(_d) ((_d) == hardware_domain)
+#define is_hardware_domain(_d) (!is_vixen() && ((_d) == hardware_domain))
 
 /* This check is for functionality specific to a control domain */
 #define is_control_domain(_d) ((_d)->is_privileged)
-- 
1.9.1


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