[PATCH v3 3/5] xen/domain: Move guest type checks into the arch_sanitise_domain_config() path

[Andrew Cooper <andrew.cooper3@citrix.com>]

This is a more appropriate location for the checks to happen, and cleans up
the common code substantially.

Take the opportunity to make ARM strictly require HVM|HAP for guests, which is
how the toolstack behaves, and leave a dprintk() behind for auditing failures.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>

v2:
 * New
v3:
 * Rewrite to retain the existing bug compatibility on the x86 side.
---
 xen/arch/arm/domain.c |  6 ++++++
 xen/arch/x86/domain.c |  8 ++++++++
 xen/common/domain.c   | 34 +++-------------------------------
 3 files changed, 17 insertions(+), 31 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index c24ace6..71ad1f9 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -601,6 +601,12 @@ void vcpu_switch_to_aarch64_mode(struct vcpu *v)
 
 int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
 {
+    if ( config->flags != (XEN_DOMCTL_CDF_hvm_guest | XEN_DOMCTL_CDF_hap) )
+    {
+        dprintk(XENLOG_INFO, "Unsupported configuration %#x\n", config->flags);
+        return -EINVAL;
+    }
+
     /* Fill in the native GIC version, passed back to the toolstack. */
     if ( config->arch.gic_version == XEN_DOMCTL_CONFIG_GIC_NATIVE )
     {
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 28a145a..272fd84 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -420,6 +420,14 @@ void arch_vcpu_destroy(struct vcpu *v)
 
 int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
 {
+    bool hvm = config->flags & XEN_DOMCTL_CDF_hvm_guest;
+
+    if ( hvm ? !hvm_enabled : !IS_ENABLED(CONFIG_PV) )
+    {
+        dprintk(XENLOG_INFO, "%s support not available\n", hvm ? "HVM" : "PV");
+        return -EINVAL;
+    }
+
     return 0;
 }
 
diff --git a/xen/common/domain.c b/xen/common/domain.c
index ddaf74a..f69f405 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -339,37 +339,9 @@ struct domain *domain_create(domid_t domid,
         hardware_domain = d;
     }
 
-    /* Sort out our idea of is_{pv,hvm}_domain(). */
-    if ( config )
-    {
-        if ( config->flags & XEN_DOMCTL_CDF_hvm_guest )
-        {
-#ifdef CONFIG_HVM
-            d->guest_type = guest_type_hvm;
-#else
-            err = -EINVAL;
-            goto fail;
-#endif
-        }
-        else
-        {
-#ifdef CONFIG_PV
-            d->guest_type = guest_type_pv;
-#else
-            err = -EINVAL;
-            goto fail;
-#endif
-        }
-    }
-    else
-    {
-        /*
-         * At least the idle domain should be treated as PV domain
-         * because it uses PV context switch functions. To err on the
-         * safe side, leave all system domains to be guest_type_pv.
-         */
-        d->guest_type = guest_type_pv;
-    }
+    /* Sort out our idea of is_{pv,hvm}_domain().  All system domains are PV. */
+    d->guest_type = ((config && (config->flags & XEN_DOMCTL_CDF_hvm_guest))
+                     ? guest_type_hvm : guest_type_pv);
 
     TRACE_1D(TRC_DOM0_DOM_ADD, d->domain_id);
 
-- 
2.1.4


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