[Xen-devel] [PATCH v6 02/10] x86/hvm/domain: remove the 'hap_enabled' flag

[Paul Durrant <paul.durrant@xxxxxxxxxx>]

The hap_enabled() macro can determine whether the feature is available
using the domain 'options'; there is no need for a separate flag.

NOTE: Furthermore, by extending sanitiziing of the domain 'options', the
      macro can be transformed into an inline function and re-located to
      xen/sched.h. This also makes hap_enabled() common, thus allowing
      removal of an ugly ifdef CONFIG_X86 from the common iommu code.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

v4:
 - Add missing perentheses and move hap_enabled()
 - Fix the shim build

v3:
 - Re-worked as suggested by Jan
 - Not adding Roger's R-b as the patch has changed substantially

v2:
 - Defer changes to shadow_domain_init() to patch #4
---
 xen/arch/x86/domain.c            | 13 +++++++------
 xen/arch/x86/mm/paging.c         |  4 ++--
 xen/common/domain.c              |  7 +++++++
 xen/drivers/passthrough/iommu.c  |  2 --
 xen/include/asm-x86/hvm/domain.h |  7 -------
 xen/include/asm-x86/paging.h     |  2 +-
 xen/include/xen/sched.h          |  6 ++++++
 7 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 9a6eb89ddc..bc0db03387 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -460,6 +460,12 @@ int arch_sanitise_domain_config(struct 
xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( (config->flags & XEN_DOMCTL_CDF_hap) && !hvm_hap_supported() )
+    {
+        dprintk(XENLOG_INFO, "HAP enabled but not supported\n");
+        return -EINVAL;
+    }
+
     return 0;
 }
 
@@ -564,12 +570,7 @@ int arch_domain_create(struct domain *d,
     HYPERVISOR_COMPAT_VIRT_START(d) =
         is_pv_domain(d) ? __HYPERVISOR_COMPAT_VIRT_START : ~0u;
 
-    /* Need to determine if HAP is enabled before initialising paging */
-    if ( is_hvm_domain(d) )
-        d->arch.hvm.hap_enabled =
-            hvm_hap_supported() && (config->flags & XEN_DOMCTL_CDF_hap);
-
-    if ( (rc = paging_domain_init(d, config->flags)) != 0 )
+    if ( (rc = paging_domain_init(d)) != 0 )
         goto fail;
     paging_initialised = true;
 
diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index 011089368a..097a27f608 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -632,7 +632,7 @@ void paging_log_dirty_init(struct domain *d, const struct 
log_dirty_ops *ops)
 /*           CODE FOR PAGING SUPPORT            */
 /************************************************/
 /* Domain paging struct initialization. */
-int paging_domain_init(struct domain *d, unsigned int domcr_flags)
+int paging_domain_init(struct domain *d)
 {
     int rc;
 
@@ -653,7 +653,7 @@ int paging_domain_init(struct domain *d, unsigned int 
domcr_flags)
     if ( hap_enabled(d) )
         hap_domain_init(d);
     else
-        rc = shadow_domain_init(d, domcr_flags);
+        rc = shadow_domain_init(d, d->options);
 
     return rc;
 }
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 744b572195..6109623730 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -313,6 +313,13 @@ static int sanitise_domain_config(struct 
xen_domctl_createdomain *config)
         return -EINVAL;
     }
 
+    if ( !(config->flags & XEN_DOMCTL_CDF_hvm_guest) &&
+         (config->flags & XEN_DOMCTL_CDF_hap) )
+    {
+        dprintk(XENLOG_INFO, "HAP enabled for non-HVM guest\n");
+        return -EINVAL;
+    }
+
     return arch_sanitise_domain_config(config);
 }
 
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index f8c3bf53bd..37eb0f7d01 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -573,9 +573,7 @@ int iommu_do_domctl(
 
 void iommu_share_p2m_table(struct domain* d)
 {
-#ifdef CONFIG_X86
     ASSERT(hap_enabled(d));
-#endif
     /*
      * iommu_use_hap_pt(d) cannot be used here because during domain
      * construction need_iommu(d) will always return false here.
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 6c7c4f5aa6..bcc5621797 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -156,7 +156,6 @@ struct hvm_domain {
 
     struct viridian_domain *viridian;
 
-    bool_t                 hap_enabled;
     bool_t                 mem_sharing_enabled;
     bool_t                 qemu_mapcache_invalidate;
     bool_t                 is_s3_suspended;
@@ -195,12 +194,6 @@ struct hvm_domain {
     };
 };
 
-#ifdef CONFIG_HVM
-#define hap_enabled(d)  (is_hvm_domain(d) && (d)->arch.hvm.hap_enabled)
-#else
-#define hap_enabled(d)  ({(void)(d); false;})
-#endif
-
 #endif /* __ASM_X86_HVM_DOMAIN_H__ */
 
 /*
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index cf57ca708d..ab7887f23c 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -207,7 +207,7 @@ void paging_vcpu_init(struct vcpu *v);
 
 /* Set up the paging-assistance-specific parts of a domain struct at
  * start of day.  Called for every domain from arch_domain_create() */
-int paging_domain_init(struct domain *d, unsigned int domcr_flags);
+int paging_domain_init(struct domain *d);
 
 /* Handler for paging-control ops: operations from user-space to enable
  * and disable ephemeral shadow modes (test mode and log-dirty mode) and
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 2e6e0d3488..07a64947ed 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -954,6 +954,12 @@ static inline bool is_hvm_vcpu(const struct vcpu *v)
     return is_hvm_domain(v->domain);
 }
 
+static inline bool hap_enabled(const struct domain *d)
+{
+    return IS_ENABLED(CONFIG_HVM) && /* necessary for pv shim build */
+        evaluate_nospec(d->options & XEN_DOMCTL_CDF_hap);
+}
+
 static inline bool is_hwdom_pinned_vcpu(const struct vcpu *v)
 {
     return (is_hardware_domain(v->domain) &&
-- 
2.20.1.2.gb21ebb671


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