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* [PATCH] x86: correct boot time page table setup
@ 2017-05-05 13:12 Jan Beulich
  2017-05-05 15:08 ` Andrew Cooper
  0 siblings, 1 reply; 3+ messages in thread
From: Jan Beulich @ 2017-05-05 13:12 UTC (permalink / raw)
  To: xen-devel; +Cc: Andrew Cooper, Julien Grall

[-- Attachment #1: Type: text/plain, Size: 2859 bytes --]

While using alloc_domheap_pages() and assuming the allocated memory is
directly accessible is okay at boot time (as we run on the idle page
tables there), memory hotplug code too assumes it can access the
resulting page tables without using map_domain_page() or alike, and
hence we need to obtain memory suitable for ordinary page table use
here.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -496,7 +496,7 @@ void __init paging_init(void)
     unsigned int n, memflags;
     l3_pgentry_t *l3_ro_mpt;
     l2_pgentry_t *l2_ro_mpt = NULL;
-    struct page_info *l1_pg, *l2_pg, *l3_pg;
+    struct page_info *l1_pg;
 
     /*
      * We setup the L3s for 1:1 mapping if host support memory hotplug
@@ -509,23 +509,22 @@ void __init paging_init(void)
         if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
               _PAGE_PRESENT) )
         {
-            l3_pg = alloc_domheap_page(NULL, 0);
-            if ( !l3_pg )
+            l3_pgentry_t *pl3t = alloc_xen_pagetable();
+
+            if ( !pl3t )
                 goto nomem;
-            l3_ro_mpt = page_to_virt(l3_pg);
-            clear_page(l3_ro_mpt);
+            clear_page(pl3t);
             l4e_write(&idle_pg_table[l4_table_offset(va)],
-                      l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RW));
+                      l4e_from_paddr(__pa(pl3t), __PAGE_HYPERVISOR_RW));
         }
     }
 
     /* Create user-accessible L2 directory to map the MPT for guests. */
-    if ( (l3_pg = alloc_domheap_page(NULL, 0)) == NULL )
+    if ( (l3_ro_mpt = alloc_xen_pagetable()) == NULL )
         goto nomem;
-    l3_ro_mpt = page_to_virt(l3_pg);
     clear_page(l3_ro_mpt);
     l4e_write(&idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)],
-              l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+              l4e_from_paddr(__pa(l3_ro_mpt), __PAGE_HYPERVISOR_RO | _PAGE_USER));
 
     /*
      * Allocate and map the machine-to-phys table.
@@ -607,12 +606,12 @@ void __init paging_init(void)
         }
         if ( !((unsigned long)l2_ro_mpt & ~PAGE_MASK) )
         {
-            if ( (l2_pg = alloc_domheap_page(NULL, memflags)) == NULL )
+            if ( (l2_ro_mpt = alloc_xen_pagetable()) == NULL )
                 goto nomem;
-            l2_ro_mpt = page_to_virt(l2_pg);
             clear_page(l2_ro_mpt);
             l3e_write(&l3_ro_mpt[l3_table_offset(va)],
-                      l3e_from_page(l2_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+                      l3e_from_paddr(__pa(l2_ro_mpt),
+                                     __PAGE_HYPERVISOR_RO | _PAGE_USER));
             ASSERT(!l2_table_offset(va));
         }
         /* NB. Cannot be GLOBAL: guest user mode should not see it. */




[-- Attachment #2: x86-hugemem-hotplug.patch --]
[-- Type: text/plain, Size: 2896 bytes --]

x86: correct boot time page table setup

While using alloc_domheap_pages() and assuming the allocated memory is
directly accessible is okay at boot time (as we run on the idle page
tables there), memory hotplug code too assumes it can access the
resulting page tables without using map_domain_page() or alike, and
hence we need to obtain memory suitable for ordinary page table use
here.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -496,7 +496,7 @@ void __init paging_init(void)
     unsigned int n, memflags;
     l3_pgentry_t *l3_ro_mpt;
     l2_pgentry_t *l2_ro_mpt = NULL;
-    struct page_info *l1_pg, *l2_pg, *l3_pg;
+    struct page_info *l1_pg;
 
     /*
      * We setup the L3s for 1:1 mapping if host support memory hotplug
@@ -509,23 +509,22 @@ void __init paging_init(void)
         if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
               _PAGE_PRESENT) )
         {
-            l3_pg = alloc_domheap_page(NULL, 0);
-            if ( !l3_pg )
+            l3_pgentry_t *pl3t = alloc_xen_pagetable();
+
+            if ( !pl3t )
                 goto nomem;
-            l3_ro_mpt = page_to_virt(l3_pg);
-            clear_page(l3_ro_mpt);
+            clear_page(pl3t);
             l4e_write(&idle_pg_table[l4_table_offset(va)],
-                      l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RW));
+                      l4e_from_paddr(__pa(pl3t), __PAGE_HYPERVISOR_RW));
         }
     }
 
     /* Create user-accessible L2 directory to map the MPT for guests. */
-    if ( (l3_pg = alloc_domheap_page(NULL, 0)) == NULL )
+    if ( (l3_ro_mpt = alloc_xen_pagetable()) == NULL )
         goto nomem;
-    l3_ro_mpt = page_to_virt(l3_pg);
     clear_page(l3_ro_mpt);
     l4e_write(&idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)],
-              l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+              l4e_from_paddr(__pa(l3_ro_mpt), __PAGE_HYPERVISOR_RO | _PAGE_USER));
 
     /*
      * Allocate and map the machine-to-phys table.
@@ -607,12 +606,12 @@ void __init paging_init(void)
         }
         if ( !((unsigned long)l2_ro_mpt & ~PAGE_MASK) )
         {
-            if ( (l2_pg = alloc_domheap_page(NULL, memflags)) == NULL )
+            if ( (l2_ro_mpt = alloc_xen_pagetable()) == NULL )
                 goto nomem;
-            l2_ro_mpt = page_to_virt(l2_pg);
             clear_page(l2_ro_mpt);
             l3e_write(&l3_ro_mpt[l3_table_offset(va)],
-                      l3e_from_page(l2_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+                      l3e_from_paddr(__pa(l2_ro_mpt),
+                                     __PAGE_HYPERVISOR_RO | _PAGE_USER));
             ASSERT(!l2_table_offset(va));
         }
         /* NB. Cannot be GLOBAL: guest user mode should not see it. */

[-- Attachment #3: Type: text/plain, Size: 127 bytes --]

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https://lists.xen.org/xen-devel

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] x86: correct boot time page table setup
  2017-05-05 13:12 [PATCH] x86: correct boot time page table setup Jan Beulich
@ 2017-05-05 15:08 ` Andrew Cooper
  2017-05-08 12:16   ` Julien Grall
  0 siblings, 1 reply; 3+ messages in thread
From: Andrew Cooper @ 2017-05-05 15:08 UTC (permalink / raw)
  To: Jan Beulich, xen-devel; +Cc: Julien Grall

On 05/05/17 14:12, Jan Beulich wrote:
> While using alloc_domheap_pages() and assuming the allocated memory is
> directly accessible is okay at boot time (as we run on the idle page
> tables there), memory hotplug code too assumes it can access the
> resulting page tables without using map_domain_page() or alike, and
> hence we need to obtain memory suitable for ordinary page table use
> here.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] x86: correct boot time page table setup
  2017-05-05 15:08 ` Andrew Cooper
@ 2017-05-08 12:16   ` Julien Grall
  0 siblings, 0 replies; 3+ messages in thread
From: Julien Grall @ 2017-05-08 12:16 UTC (permalink / raw)
  To: Andrew Cooper, Jan Beulich, xen-devel

Hi,

On 05/05/17 16:08, Andrew Cooper wrote:
> On 05/05/17 14:12, Jan Beulich wrote:
>> While using alloc_domheap_pages() and assuming the allocated memory is
>> directly accessible is okay at boot time (as we run on the idle page
>> tables there), memory hotplug code too assumes it can access the
>> resulting page tables without using map_domain_page() or alike, and
>> hence we need to obtain memory suitable for ordinary page table use
>> here.
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

Release-acked-by: Julien Grall <julien.grall@arm.com>

Cheers,


-- 
Julien Grall


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Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel

^ permalink raw reply	[flat|nested] 3+ messages in thread
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2017-05-05 13:12 [PATCH] x86: correct boot time page table setup Jan Beulich
2017-05-05 15:08 ` Andrew Cooper
2017-05-08 12:16   ` Julien Grall

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