[Xen-devel] [PATCH 10/18] arm/altp2m: Renamed and extended p2m_alloc_table.

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

The initially named function "p2m_alloc_table" allocated pages solely
required for p2m. The new implementation leaves p2m allocation related
parts inside of this function (which is made static) and provides an
overlay function "p2m_table_init" that can be called from extern to
generally initialize p2m tables.  Therefore, it distinguishes between
the domain's p2m and altp2m mappings, which are allocated similarly.

NOTE: Inside the function "p2m_alloc_table" we do not lock the p2m lock
anymore. Also, we flush the TLBs outside of the function
"p2m_alloc_table". Instead, we perform the associate locking and TLB
flushing as part of the function p2m_table_init. This allows us to
provide a uniform interface for p2m-related table allocation, which can
be used for altp2m (and potentially nested p2m tables in the future
implementation) -- as it is done in the x86 implementation.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/domain.c     |  2 +-
 xen/arch/arm/p2m.c        | 53 +++++++++++++++++++++++++++++++++++++----------
 xen/include/asm-arm/p2m.h |  2 +-
 3 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 6ce4645..6102ed0 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -573,7 +573,7 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
     if ( (rc = domain_io_init(d)) != 0 )
         goto fail;
 
-    if ( (rc = p2m_alloc_table(d)) != 0 )
+    if ( (rc = p2m_table_init(d)) != 0 )
         goto fail;
 
     switch ( config->gic_version )
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 8bf23ee..7e721f9 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1315,35 +1315,66 @@ void guest_physmap_remove_page(struct domain *d,
                       d->arch.p2m.default_access);
 }
 
-int p2m_alloc_table(struct domain *d)
+static int p2m_alloc_table(struct p2m_domain *p2m)
 {
-    struct p2m_domain *p2m = &d->arch.p2m;
-    struct page_info *page;
+    struct page_info *page = NULL;
     unsigned int i;
 
     page = alloc_domheap_pages(NULL, P2M_ROOT_ORDER, 0);
     if ( page == NULL )
         return -ENOMEM;
 
-    spin_lock(&p2m->lock);
-
-    /* Clear both first level pages */
+    /* Clear all first level pages */
     for ( i = 0; i < P2M_ROOT_PAGES; i++ )
         clear_and_clean_page(page + i);
 
     p2m->root = page;
 
-    d->arch.vttbr = page_to_maddr(p2m->root)
-        | ((uint64_t)p2m->vmid&0xff)<<48;
+    p2m->vttbr.vttbr = 0;
+    p2m->vttbr.vttbr_vmid = p2m->vmid & 0xff;
+    p2m->vttbr.vttbr_baddr = page_to_maddr(p2m->root);
 
-    /* Make sure that all TLBs corresponding to the new VMID are flushed
-     * before using it
+    return 0;
+}
+
+int p2m_table_init(struct domain *d)
+{
+    int i = 0;
+    int rc = -ENOMEM;
+    struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+    spin_lock(&p2m->lock);
+
+    rc = p2m_alloc_table(p2m);
+    if ( rc != 0 )
+        goto out;
+
+    d->arch.vttbr = d->arch.p2m.vttbr.vttbr;
+
+    /*
+     * Make sure that all TLBs corresponding to the new VMID are flushed
+     * before using it.
      */
     flush_tlb_domain(d);
 
     spin_unlock(&p2m->lock);
 
-    return 0;
+    if ( hvm_altp2m_supported() )
+    {
+        /* Init alternate p2m data */
+        for ( i = 0; i < MAX_ALTP2M; i++ )
+        {
+            d->arch.altp2m_vttbr[i] = INVALID_MFN;
+            rc = p2m_alloc_table(d->arch.altp2m_p2m[i]);
+            if ( rc != 0 )
+                goto out;
+        }
+
+        d->arch.altp2m_active = 0;
+    }
+
+out:
+    return rc;
 }
 
 #define MAX_VMID 256
diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
index 783db5c..451b097 100644
--- a/xen/include/asm-arm/p2m.h
+++ b/xen/include/asm-arm/p2m.h
@@ -171,7 +171,7 @@ int relinquish_p2m_mapping(struct domain *d);
  *
  * Returns 0 for success or -errno.
  */
-int p2m_alloc_table(struct domain *d);
+int p2m_table_init(struct domain *d);
 
 /* Context switch */
 void p2m_save_state(struct vcpu *p);
-- 
2.8.3


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