[Xen-devel] [PATCH 07/17] ARM: VGIC: Adjust domain_max_vcpus() to be VGIC specific

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

domain_max_vcpus(), which is used by generic Xen code, returns the
maximum number of VCPUs for a domain, which on ARM is mostly limited by
the VGIC model emulated (a (v)GICv2 can only handle 8 CPUs).
Our current implementation lives in arch/arm/domain.c, but reaches into
VGIC internal data structures.
Move the actual functionality into vgic.c, and provide a shim in
domain.h, to keep this VGIC internal.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
---
Changelog:
- rename helper function and wrap in domain.h

 xen/arch/arm/domain.c        | 14 --------------
 xen/arch/arm/vgic.c          | 14 ++++++++++++++
 xen/include/asm-arm/domain.h |  6 +++++-
 xen/include/asm-arm/vgic.h   |  2 ++
 4 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 8de4c0a343..6b902fa30f 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -967,20 +967,6 @@ void vcpu_block_unless_event_pending(struct vcpu *v)
         vcpu_unblock(current);
 }
 
-unsigned int domain_max_vcpus(const struct domain *d)
-{
-    /*
-     * Since evtchn_init would call domain_max_vcpus for poll_mask
-     * allocation when the vgic_ops haven't been initialised yet,
-     * we return MAX_VIRT_CPUS if d->arch.vgic.handler is null.
-     */
-    if ( !d->arch.vgic.handler )
-        return MAX_VIRT_CPUS;
-    else
-        return min_t(unsigned int, MAX_VIRT_CPUS,
-                     d->arch.vgic.handler->max_vcpus);
-}
-
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 34269bcf27..fa00c21a69 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -665,6 +665,20 @@ void vgic_free_virq(struct domain *d, unsigned int virq)
     clear_bit(virq, d->arch.vgic.allocated_irqs);
 }
 
+unsigned int vgic_max_vcpus(const struct domain *d)
+{
+    /*
+     * Since evtchn_init would call domain_max_vcpus for poll_mask
+     * allocation when the vgic_ops haven't been initialised yet,
+     * we return MAX_VIRT_CPUS if d->arch.vgic.handler is null.
+     */
+    if ( !d->arch.vgic.handler )
+        return MAX_VIRT_CPUS;
+    else
+        return min_t(unsigned int, MAX_VIRT_CPUS,
+                     d->arch.vgic.handler->max_vcpus);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index c6aa5cf389..e730e07fcf 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -289,7 +289,11 @@ void vcpu_show_execution_state(struct vcpu *);
 void vcpu_show_registers(const struct vcpu *);
 void vcpu_switch_to_aarch64_mode(struct vcpu *);
 
-unsigned int domain_max_vcpus(const struct domain *);
+/* On ARM, the number of VCPUs is limited by the type of GIC emulated. */
+static inline unsigned int domain_max_vcpus(const struct domain *d)
+{
+    return vgic_max_vcpus(d);
+}
 
 /*
  * Due to the restriction of GICv3, the number of vCPUs in AFF0 is
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index d03298e12c..afb4776ad4 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -254,6 +254,8 @@ static inline int vgic_allocate_spi(struct domain *d)
 
 extern void vgic_free_virq(struct domain *d, unsigned int virq);
 
+unsigned int vgic_max_vcpus(const struct domain *d);
+
 void vgic_v2_setup_hw(paddr_t dbase, paddr_t cbase, paddr_t csize,
                       paddr_t vbase, uint32_t aliased_offset);
 
-- 
2.14.1


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