[Xen-devel] [PATCH v2] x86/vcpu: Remove struct vcpu allocation restriction when possible

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

There is no need for struct vcpu to live below the 4G boundary for PV guests,
or for HVM vcpus using HAP.

Plumb struct domain into alloc_vcpu_struct() so the x86 version can query the
domain's type and paging settings.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

v2:
 * Plumb struct domain into alloc_vcpu_struct()
---
 xen/arch/arm/domain.c    | 2 +-
 xen/arch/x86/domain.c    | 7 +++++--
 xen/common/domain.c      | 2 +-
 xen/include/xen/domain.h | 2 +-
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index feebbf5..8043287 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -516,7 +516,7 @@ void dump_pageframe_info(struct domain *d)
 #define MAX_PAGES_PER_VCPU  1
 #endif
 
-struct vcpu *alloc_vcpu_struct(void)
+struct vcpu *alloc_vcpu_struct(const struct domain *d)
 {
     struct vcpu *v;
 
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 943f95b..f6fe954 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -302,7 +302,7 @@ void free_domain_struct(struct domain *d)
     free_xenheap_page(d);
 }
 
-struct vcpu *alloc_vcpu_struct(void)
+struct vcpu *alloc_vcpu_struct(const struct domain *d)
 {
     struct vcpu *v;
     /*
@@ -311,8 +311,11 @@ struct vcpu *alloc_vcpu_struct(void)
      * may require that the shadow CR3 points below 4GB, and hence the whole
      * structure must satisfy this restriction. Thus we specify MEMF_bits(32).
      */
+    unsigned int memflags =
+        (is_hvm_domain(d) && paging_mode_shadow(d)) ? MEMF_bits(32) : 0;
+
     BUILD_BUG_ON(sizeof(*v) > PAGE_SIZE);
-    v = alloc_xenheap_pages(0, MEMF_bits(32));
+    v = alloc_xenheap_pages(0, memflags);
     if ( v != NULL )
         clear_page(v);
     return v;
diff --git a/xen/common/domain.c b/xen/common/domain.c
index b8d4848..d6650f0 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -140,7 +140,7 @@ struct vcpu *vcpu_create(
 
     BUG_ON((!is_idle_domain(d) || vcpu_id) && d->vcpu[vcpu_id]);
 
-    if ( (v = alloc_vcpu_struct()) == NULL )
+    if ( (v = alloc_vcpu_struct(d)) == NULL )
         return NULL;
 
     v->domain = d;
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 5e393fd..33e4148 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -36,7 +36,7 @@ struct domain *alloc_domain_struct(void);
 void free_domain_struct(struct domain *d);
 
 /* Allocate/free a VCPU structure. */
-struct vcpu *alloc_vcpu_struct(void);
+struct vcpu *alloc_vcpu_struct(const struct domain *d);
 void free_vcpu_struct(struct vcpu *v);
 
 /* Allocate/free a PIRQ structure. */
-- 
2.1.4


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