[PATCH v5 3/7] xen/arm: SMP support

From: Stefano Stabellini
Date: Thu Apr 25 2013 - 12:58:19 EST


Map vcpu_info using VCPUOP_register_vcpu_info on all the online vcpus,
make sure the allocated struct doesn't cross a page boundary.

Call enable_percpu_irq on every cpu.

Changes in v5:
- allocate xen_vcpu_info dynamically, aligning it to the size of the
struct;
- use VCPUOP_register_vcpu_info on cpu0 too.

Changed in v2:
- move the percpu variable argument fix to a separate patch;
- remove unused variable.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
arch/arm/xen/enlighten.c | 48 ++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 82d5e63..6c87d11 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -2,6 +2,7 @@
#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/hvm.h>
+#include <xen/interface/vcpu.h>
#include <xen/interface/xen.h>
#include <xen/interface/memory.h>
#include <xen/interface/hvm/params.h>
@@ -32,6 +33,7 @@ struct shared_info xen_dummy_shared_info;
struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;

DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
+static struct vcpu_info __percpu *xen_vcpu_info;

/* These are unused until we support booting "pre-ballooned" */
unsigned long xen_released_pages;
@@ -148,6 +150,29 @@ int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
}
EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);

+static int __init xen_secondary_init(unsigned int cpu)
+{
+ struct vcpu_register_vcpu_info info;
+ struct vcpu_info *vcpup;
+ int err;
+
+ pr_info("Xen: initializing cpu%d\n", cpu);
+ vcpup = per_cpu_ptr(xen_vcpu_info, cpu);
+
+ info.mfn = __pa(vcpup) >> PAGE_SHIFT;
+ info.offset = offset_in_page(vcpup);
+
+ err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
+ if (err) {
+ pr_debug("register_vcpu_info failed: err=%d\n", err);
+ } else {
+ /* This cpu is using the registered vcpu info, even if
+ later ones fail to. */
+ per_cpu(xen_vcpu, cpu) = vcpup;
+ }
+ return 0;
+}
+
/*
* see Documentation/devicetree/bindings/arm/xen.txt for the
* documentation of the Xen Device Tree format.
@@ -163,6 +188,7 @@ static int __init xen_guest_init(void)
const char *version = NULL;
const char *xen_prefix = "xen,xen-";
struct resource res;
+ int i;

node = of_find_compatible_node(NULL, NULL, "xen,xen");
if (!node) {
@@ -209,13 +235,18 @@ static int __init xen_guest_init(void)

/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
* page, we use it in the event channel upcall and in some pvclock
- * related functions. We don't need the vcpu_info placement
- * optimizations because we don't use any pv_mmu or pv_irq op on
- * HVM.
+ * related functions.
* The shared info contains exactly 1 CPU (the boot CPU). The guest
* is required to use VCPUOP_register_vcpu_info to place vcpu info
- * for secondary CPUs as they are brought up. */
- per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
+ * for secondary CPUs as they are brought up.
+ * For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
+ */
+ xen_vcpu_info = __alloc_percpu(sizeof(struct vcpu_info),
+ sizeof(struct vcpu_info));
+ if (xen_vcpu_info == NULL)
+ return -ENOMEM;
+ for_each_online_cpu(i)
+ xen_secondary_init(i);

gnttab_init();
if (!xen_initial_domain())
@@ -231,6 +262,11 @@ static irqreturn_t xen_arm_callback(int irq, void *arg)
return IRQ_HANDLED;
}

+static __init void xen_percpu_enable_events(void *unused)
+{
+ enable_percpu_irq(xen_events_irq, 0);
+}
+
static int __init xen_init_events(void)
{
if (!xen_domain() || xen_events_irq < 0)
@@ -244,7 +280,7 @@ static int __init xen_init_events(void)
return -EINVAL;
}

- enable_percpu_irq(xen_events_irq, 0);
+ on_each_cpu(xen_percpu_enable_events, NULL, 0);

return 0;
}
--
1.7.2.5

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