[PATCH v2 11/12] xen/dom0: Arrange for dom0_cfg to contain the real max_vcpus value

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

Make dom0_max_vcpus() a common interface, and implement it on ARM by splitting
the existing alloc_dom0_vcpu0() function in half.

As domain_create() doesn't yet set up the vcpu array, the max value is also
passed into alloc_dom0_vcpu0().  This is temporary for bisectibility and
removed in the following patch.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Wei Liu <wei.liu2@citrix.com>
---
 xen/arch/arm/domain_build.c | 12 +++++++++---
 xen/arch/arm/setup.c        |  3 ++-
 xen/arch/x86/dom0_build.c   |  5 ++---
 xen/arch/x86/setup.c        |  3 ++-
 xen/include/asm-x86/setup.h |  2 --
 xen/include/xen/domain.h    |  5 ++++-
 6 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 737e0f3..f4a1225 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -62,17 +62,23 @@ struct map_range_data
  */
 #define DOM0_FDT_EXTRA_SIZE (128 + sizeof(struct fdt_reserve_entry))
 
-struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
+unsigned int __init dom0_max_vcpus(void)
 {
     if ( opt_dom0_max_vcpus == 0 )
         opt_dom0_max_vcpus = num_online_cpus();
     if ( opt_dom0_max_vcpus > MAX_VIRT_CPUS )
         opt_dom0_max_vcpus = MAX_VIRT_CPUS;
 
-    dom0->vcpu = xzalloc_array(struct vcpu *, opt_dom0_max_vcpus);
+    return opt_dom0_max_vcpus;
+}
+
+struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0,
+                                     unsigned int max_vcpus)
+{
+    dom0->vcpu = xzalloc_array(struct vcpu *, max_vcpus);
     if ( !dom0->vcpu )
         return NULL;
-    dom0->max_vcpus = opt_dom0_max_vcpus;
+    dom0->max_vcpus = max_vcpus;
 
     return alloc_vcpu(dom0, 0, 0);
 }
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 3d3b30c..72e42e8 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -860,9 +860,10 @@ void __init start_xen(unsigned long boot_phys_offset,
     /* The vGIC for DOM0 is exactly emulating the hardware GIC */
     dom0_cfg.arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
     dom0_cfg.arch.nr_spis = gic_number_lines() - 32;
+    dom0_cfg.max_vcpus = dom0_max_vcpus();
 
     dom0 = domain_create(0, &dom0_cfg, true);
-    if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
+    if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0, dom0_cfg.max_vcpus) == NULL) )
             panic("Error creating domain 0");
 
     if ( construct_dom0(dom0) != 0)
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index b744791..b42eac3 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -199,10 +199,9 @@ unsigned int __init dom0_max_vcpus(void)
     return max_vcpus;
 }
 
-struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
+struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0,
+                                     unsigned int max_vcpus)
 {
-    unsigned int max_vcpus = dom0_max_vcpus();
-
     dom0->node_affinity = dom0_nodes;
     dom0->auto_node_affinity = !dom0_nr_pxms;
 
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 2cfae89..46dcc71 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1689,10 +1689,11 @@ void __init noreturn __start_xen(unsigned long mbi_p)
         dom0_cfg.arch.emulation_flags |=
             XEN_X86_EMU_LAPIC | XEN_X86_EMU_IOAPIC | XEN_X86_EMU_VPCI;
     }
+    dom0_cfg.max_vcpus = dom0_max_vcpus();
 
     /* Create initial domain 0. */
     dom0 = domain_create(get_initial_domain_id(), &dom0_cfg, !pv_shim);
-    if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
+    if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0, dom0_cfg.max_vcpus) == NULL) )
         panic("Error creating domain 0");
 
     /* Grab the DOM0 command line. */
diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
index b2bf16c..42fddeb 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -44,8 +44,6 @@ unsigned long initial_images_nrpages(nodeid_t node);
 void discard_initial_images(void);
 void *bootstrap_map(const module_t *mod);
 
-unsigned int dom0_max_vcpus(void);
-
 int xen_in_range(unsigned long mfn);
 
 void microcode_grab_module(
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index f35e360..651205d 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -15,7 +15,10 @@ typedef union {
 
 struct vcpu *alloc_vcpu(
     struct domain *d, unsigned int vcpu_id, unsigned int cpu_id);
-struct vcpu *alloc_dom0_vcpu0(struct domain *dom0);
+
+unsigned int dom0_max_vcpus(void);
+struct vcpu *alloc_dom0_vcpu0(struct domain *dom0, unsigned int max_vcpus);
+
 int vcpu_reset(struct vcpu *);
 int vcpu_up(struct vcpu *v);
 
-- 
2.1.4


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