[RFC XEN PATCH 05/16] xen/x86: release pmem pages at domain destroy

[Haozhong Zhang <haozhong.zhang@intel.com>]

The host pmem pages mapped to a domain are unassigned at domain destroy
so as to be used by other domains in future.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
---
 xen/arch/x86/domain.c  |  5 +++++
 xen/arch/x86/pmem.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 xen/include/xen/pmem.h |  1 +
 3 files changed, 47 insertions(+)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 1bd5eb6..05ab389 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -61,6 +61,7 @@
 #include <asm/amd.h>
 #include <xen/numa.h>
 #include <xen/iommu.h>
+#include <xen/pmem.h>
 #include <compat/vcpu.h>
 #include <asm/psr.h>
 
@@ -2512,6 +2513,10 @@ int domain_relinquish_resources(struct domain *d)
         if ( ret )
             return ret;
 
+        ret = pmem_teardown(d);
+        if ( ret )
+            return ret;
+
         /* Tear down paging-assistance stuff. */
         ret = paging_teardown(d);
         if ( ret )
diff --git a/xen/arch/x86/pmem.c b/xen/arch/x86/pmem.c
index e4dc685..50e496b 100644
--- a/xen/arch/x86/pmem.c
+++ b/xen/arch/x86/pmem.c
@@ -282,3 +282,44 @@ int pmem_populate(struct xen_pmemmap_args *args)
     args->nr_done = i;
     return rc;
 }
+
+static int pmem_teardown_preemptible(struct domain *d, int *preempted)
+{
+    struct page_info *pg, *next;
+    int rc = 0;
+
+    spin_lock(&d->pmem_lock);
+
+    page_list_for_each_safe (pg, next, &d->pmem_page_list )
+    {
+        BUG_ON(page_get_owner(pg) != d);
+        BUG_ON(page_state_is(pg, free));
+
+        page_list_del(pg, &d->pmem_page_list);
+        page_set_owner(pg, NULL);
+        pg->count_info = (pg->count_info & ~PGC_count_mask) | PGC_state_free;
+
+        if ( preempted && hypercall_preempt_check() )
+        {
+            *preempted = 1;
+            goto out;
+        }
+    }
+
+ out:
+    spin_unlock(&d->pmem_lock);
+    return rc;
+}
+
+int pmem_teardown(struct domain *d)
+{
+    int preempted = 0;
+
+    ASSERT(d->is_dying);
+    ASSERT(d != current->domain);
+
+    if ( !has_hvm_container_domain(d) || !paging_mode_translate(d) )
+        return -EINVAL;
+
+    return pmem_teardown_preemptible(d, &preempted);
+}
diff --git a/xen/include/xen/pmem.h b/xen/include/xen/pmem.h
index 60adf56..ffbef1c 100644
--- a/xen/include/xen/pmem.h
+++ b/xen/include/xen/pmem.h
@@ -37,5 +37,6 @@ int pmem_add(unsigned long spfn, unsigned long epfn,
              unsigned long rsv_spfn, unsigned long rsv_epfn,
              unsigned long data_spfn, unsigned long data_epfn);
 int pmem_populate(struct xen_pmemmap_args *args);
+int pmem_teardown(struct domain *d);
 
 #endif /* __XEN_PMEM_H__ */
-- 
2.10.1


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