File 22780-pod-preempt.patch of Package xen.import4929
References: bnc#678871
# HG changeset patch
# User George Dunlap <george.dunlap@eu.citrix.com>
# Date 1295274253 0
# Node ID 97ab84aca65cdcbce2ddccc51629fb24adb056cf
# Parent d1631540bcc4d369d7e7ec1d87e54e1a8f5d5f78
PoD: Allow pod_set_cache_target hypercall to be preempted
For very large VMs, setting the cache target can take long enough that
dom0 complains of soft lockups. Allow the hypercall to be preempted.
Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Tim Deegan <Tim.Deegan@citrix.com>
Index: xen-4.0.2-testing/xen/arch/x86/domain.c
===================================================================
--- xen-4.0.2-testing.orig/xen/arch/x86/domain.c
+++ xen-4.0.2-testing/xen/arch/x86/domain.c
@@ -1709,8 +1709,8 @@ int hypercall_xlat_continuation(unsigned
unsigned long nval = 0;
va_list args;
- BUG_ON(*id > 5);
- BUG_ON(mask & (1U << *id));
+ BUG_ON(id && *id > 5);
+ BUG_ON(id && (mask & (1U << *id)));
va_start(args, mask);
Index: xen-4.0.2-testing/xen/arch/x86/mm.c
===================================================================
--- xen-4.0.2-testing.orig/xen/arch/x86/mm.c
+++ xen-4.0.2-testing/xen/arch/x86/mm.c
@@ -4547,14 +4547,22 @@ long arch_memory_op(int op, XEN_GUEST_HA
rc = p2m_pod_set_mem_target(d, target.target_pages);
}
- target.tot_pages = d->tot_pages;
- target.pod_cache_pages = d->arch.p2m->pod.count;
- target.pod_entries = d->arch.p2m->pod.entry_count;
-
- if ( copy_to_guest(arg, &target, 1) )
+ if ( rc == -EAGAIN )
+ {
+ rc = hypercall_create_continuation(
+ __HYPERVISOR_memory_op, "lh", op, arg);
+ }
+ else if ( rc >= 0 )
{
- rc= -EFAULT;
- goto pod_target_out_unlock;
+ target.tot_pages = d->tot_pages;
+ target.pod_cache_pages = d->arch.p2m->pod.count;
+ target.pod_entries = d->arch.p2m->pod.entry_count;
+
+ if ( copy_to_guest(arg, &target, 1) )
+ {
+ rc= -EFAULT;
+ goto pod_target_out_unlock;
+ }
}
pod_target_out_unlock:
Index: xen-4.0.2-testing/xen/arch/x86/mm/p2m.c
===================================================================
--- xen-4.0.2-testing.orig/xen/arch/x86/mm/p2m.c
+++ xen-4.0.2-testing/xen/arch/x86/mm/p2m.c
@@ -383,7 +383,7 @@ static struct page_info * p2m_pod_cache_
/* Set the size of the cache, allocating or freeing as necessary. */
static int
-p2m_pod_set_cache_target(struct domain *d, unsigned long pod_target)
+p2m_pod_set_cache_target(struct domain *d, unsigned long pod_target, int preemptible)
{
struct p2m_domain *p2md = d->arch.p2m;
int ret = 0;
@@ -416,6 +416,12 @@ p2m_pod_set_cache_target(struct domain *
}
p2m_pod_cache_add(d, page, order);
+
+ if ( hypercall_preempt_check() && preemptible )
+ {
+ ret = -EAGAIN;
+ goto out;
+ }
}
/* Decreasing the target */
@@ -460,6 +466,12 @@ p2m_pod_set_cache_target(struct domain *
put_page(page+i);
put_page(page+i);
+
+ if ( hypercall_preempt_check() && preemptible )
+ {
+ ret = -EAGAIN;
+ goto out;
+ }
}
}
@@ -537,7 +549,7 @@ p2m_pod_set_mem_target(struct domain *d,
ASSERT( pod_target >= p2md->pod.count );
- ret = p2m_pod_set_cache_target(d, pod_target);
+ ret = p2m_pod_set_cache_target(d, pod_target, 1/*preemptible*/);
out:
p2m_unlock(p2md);
@@ -701,7 +713,7 @@ out_entry_check:
/* If we've reduced our "liabilities" beyond our "assets", free some */
if ( p2md->pod.entry_count < p2md->pod.count )
{
- p2m_pod_set_cache_target(d, p2md->pod.entry_count);
+ p2m_pod_set_cache_target(d, p2md->pod.entry_count, 0/*can't preempt*/);
}
out_unlock:
Index: xen-4.0.2-testing/xen/arch/x86/x86_64/compat/mm.c
===================================================================
--- xen-4.0.2-testing.orig/xen/arch/x86/x86_64/compat/mm.c
+++ xen-4.0.2-testing/xen/arch/x86/x86_64/compat/mm.c
@@ -127,6 +127,9 @@ int compat_arch_memory_op(int op, XEN_GU
if ( rc < 0 )
break;
+ if ( rc == __HYPERVISOR_memory_op )
+ hypercall_xlat_continuation(NULL, 0x2, nat, arg);
+
XLAT_pod_target(&cmp, nat);
if ( copy_to_guest(arg, &cmp, 1) )