[Xen-devel] [PATCH v3 13/38] arm/p2m: Change func prototype and impl of p2m_(alloc|free)_vmid

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

This commit changes the prototype and implementation of the functions
"p2m_alloc_vmid" and "p2m_free_vmid". The function "p2m_alloc_vmid" does
not expect the struct domain as argument anymore and returns an
allocated vmid. The function "p2m_free_vmid" takes only the vmid that is
to be freed as argument.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
v3: Changed function prototypes and implementation of the functions
    "p2m_alloc_vmid" and "p2m_free_vmid".

    Changes in "p2m_alloc_vmid":
    This function does not expect any arguments. Also, in this commit,
    the function "p2m_alloc_vmid" returns either the successfully
    allocated vmid or the value INVALID_VMID. Thus, it is now the
    responsibility of the caller to set the returned vmid in the
    associated fields.

    Changes in "p2m_free_vmid":
    This function expects now only the vmid of type uint8_t.
---
 xen/arch/arm/p2m.c | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index a295fdc..23ceb96 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1204,11 +1204,9 @@ void p2m_vmid_allocator_init(void)
     set_bit(INVALID_VMID, vmid_mask);
 }
 
-static int p2m_alloc_vmid(struct domain *d)
+static uint8_t p2m_alloc_vmid(void)
 {
-    struct p2m_domain *p2m = p2m_get_hostp2m(d);
-
-    int rc, vmid;
+    uint8_t vmid;
 
     spin_lock(&vmid_alloc_lock);
 
@@ -1218,28 +1216,23 @@ static int p2m_alloc_vmid(struct domain *d)
 
     if ( vmid == MAX_VMID )
     {
-        rc = -EBUSY;
-        printk(XENLOG_ERR "p2m.c: dom%d: VMID pool exhausted\n", d->domain_id);
+        vmid = INVALID_VMID;
+        printk(XENLOG_ERR "p2m.c: VMID pool exhausted\n");
         goto out;
     }
 
     set_bit(vmid, vmid_mask);
 
-    p2m->vmid = vmid;
-
-    rc = 0;
-
 out:
     spin_unlock(&vmid_alloc_lock);
-    return rc;
+    return vmid;
 }
 
-static void p2m_free_vmid(struct domain *d)
+static void p2m_free_vmid(uint8_t vmid)
 {
-    struct p2m_domain *p2m = p2m_get_hostp2m(d);
     spin_lock(&vmid_alloc_lock);
-    if ( p2m->vmid != INVALID_VMID )
-        clear_bit(p2m->vmid, vmid_mask);
+    if ( vmid != INVALID_VMID )
+        clear_bit(vmid, vmid_mask);
 
     spin_unlock(&vmid_alloc_lock);
 }
@@ -1282,7 +1275,7 @@ void p2m_teardown_one(struct p2m_domain *p2m)
 
     p2m->root = NULL;
 
-    p2m_free_vmid(p2m->domain);
+    p2m_free_vmid(p2m->vmid);
 
     p2m->vttbr = INVALID_VTTBR;
 
@@ -1291,16 +1284,12 @@ void p2m_teardown_one(struct p2m_domain *p2m)
 
 int p2m_init_one(struct domain *d, struct p2m_domain *p2m)
 {
-    int rc = 0;
-
     rwlock_init(&p2m->lock);
     INIT_PAGE_LIST_HEAD(&p2m->pages);
 
-    p2m->vmid = INVALID_VMID;
-
-    rc = p2m_alloc_vmid(d);
-    if ( rc != 0 )
-        return rc;
+    p2m->vmid = p2m_alloc_vmid();
+    if ( p2m->vmid == INVALID_VMID )
+        return -EBUSY;
 
     p2m->max_mapped_gfn = _gfn(0);
     p2m->lowest_mapped_gfn = INVALID_GFN;
-- 
2.9.0


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