Attachment 278811 Details for Bug 316371 – Fail attempts to add pages to guest pseudophys memory map above 4GB when running with AMD NPT on PAE host

[patch] Fail attempts to add pages to guest pseudophys memory map above 4GB when running with AMD NPT on PAE host

Fix4GBPAEGuestMemory.patch (text/plain), 6.12 KB, created by Bhavna Sarathy on 2007-12-05 21:30:47 UTC

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Creator: Bhavna Sarathy

Created: 2007-12-05 21:30:47 UTC

Size: 6.12 KB

patch

obsolete

># HG changeset patch
># User Keir Fraser <keir@xensource.com>
># Date 1193825262 0
># Node ID 2717128cbdd11da80c5276aaa7b1a4992cfbf6f2
># Parent  c7d5d229f19122a8aad10dac178a4f86f39d73f0
>hvm: Fail attempts to add pages to guest pseudophys memory map above
>4GB when running with AMD NPT on PAE host.
>From: Wei Huang <Wei.Huang2@amd.com>
>Signed-off-by: Keir Fraser <keir@xensource.com>
>
>diff -r c7d5d229f191 -r 2717128cbdd1 xen/arch/x86/hvm/hvm.c
>--- a/xen/arch/x86/hvm/hvm.c	Wed Oct 31 09:36:45 2007 +0000
>+++ b/xen/arch/x86/hvm/hvm.c	Wed Oct 31 10:07:42 2007 +0000
>@@ -53,10 +53,11 @@
> /*
>  * Xen command-line option to allow/disallow hardware-assisted paging.
>  * Since the phys-to-machine table of AMD NPT is in host format, 32-bit Xen
>- * could only support guests using NPT with up to a 4GB memory map. Therefore
>- * we only allow HAP by default on 64-bit Xen.
>+ * can only support guests using NPT with up to a 4GB memory map. Therefore
>+ * we disallow HAP by default on PAE Xen (by default we want to support an
>+ * 8GB pseudophysical memory map for HVM guests on a PAE host).
>  */
>-static int opt_hap_permitted = (BITS_PER_LONG == 8);
>+static int opt_hap_permitted = (CONFIG_PAGING_LEVELS != 3);
> boolean_param("hap", opt_hap_permitted);
> 
> int hvm_enabled __read_mostly;
>diff -r c7d5d229f191 -r 2717128cbdd1 xen/arch/x86/mm/p2m.c
>--- a/xen/arch/x86/mm/p2m.c	Wed Oct 31 09:36:45 2007 +0000
>+++ b/xen/arch/x86/mm/p2m.c	Wed Oct 31 10:07:42 2007 +0000
>@@ -219,15 +219,17 @@ set_p2m_entry(struct domain *d, unsigned
>         goto out;
> #endif
> #if CONFIG_PAGING_LEVELS >= 3
>-    // When using PAE Xen, we only allow 33 bits of pseudo-physical
>-    // address in translated guests (i.e. 8 GBytes).  This restriction
>-    // comes from wanting to map the P2M table into the 16MB RO_MPT hole
>-    // in Xen's address space for translated PV guests.
>-    //
>+    /*
>+     * When using PAE Xen, we only allow 33 bits of pseudo-physical
>+     * address in translated guests (i.e. 8 GBytes).  This restriction
>+     * comes from wanting to map the P2M table into the 16MB RO_MPT hole
>+     * in Xen's address space for translated PV guests.
>+     * When using AMD's NPT on PAE Xen, we are restricted to 4GB.
>+     */
>     if ( !p2m_next_level(d, &table_mfn, &table, &gfn_remainder, gfn,
>                          L3_PAGETABLE_SHIFT - PAGE_SHIFT,
>-                         (CONFIG_PAGING_LEVELS == 3
>-                          ? 8
>+                         ((CONFIG_PAGING_LEVELS == 3)
>+                          ? (hvm_funcs.hap_supported ? 4 : 8)
>                           : L3_PAGETABLE_ENTRIES),
>                          PGT_l2_page_table) )
>         goto out;
>@@ -686,16 +688,26 @@ guest_physmap_remove_page(struct domain 
>     p2m_unlock(d);
> }
> 
>-void
>+int
> guest_physmap_add_entry(struct domain *d, unsigned long gfn,
>                         unsigned long mfn, p2m_type_t t)
> {
>     unsigned long ogfn;
>     p2m_type_t ot;
>     mfn_t omfn;
>+    int rc = 0;
> 
>     if ( !paging_mode_translate(d) )
>-        return;
>+        return -EINVAL;
>+
>+#if CONFIG_PAGING_LEVELS == 3
>+    /* 32bit PAE nested paging does not support over 4GB guest due to 
>+     * hardware translation limit. This limitation is checked by comparing
>+     * gfn with 0xfffffUL.
>+     */
>+    if ( paging_mode_hap(d) && (gfn > 0xfffffUL) )
>+        return -EINVAL;
>+#endif
> 
>     p2m_lock(d);
>     audit_p2m(d);
>@@ -735,18 +747,22 @@ guest_physmap_add_entry(struct domain *d
> 
>     if ( mfn_valid(_mfn(mfn)) ) 
>     {
>-        set_p2m_entry(d, gfn, _mfn(mfn), t);
>+        if ( !set_p2m_entry(d, gfn, _mfn(mfn), t) )
>+            rc = -EINVAL;
>         set_gpfn_from_mfn(mfn, gfn);
>     }
>     else
>     {
>         gdprintk(XENLOG_WARNING, "Adding bad mfn to p2m map (%#lx -> %#lx)\n",
>                  gfn, mfn);
>-        set_p2m_entry(d, gfn, _mfn(INVALID_MFN), p2m_invalid);
>+        if ( !set_p2m_entry(d, gfn, _mfn(INVALID_MFN), p2m_invalid) )
>+            rc = -EINVAL;
>     }
> 
>     audit_p2m(d);
>     p2m_unlock(d);
>+
>+    return rc;
> }
> 
> /* Walk the whole p2m table, changing any entries of the old type
>diff -r c7d5d229f191 -r 2717128cbdd1 xen/common/memory.c
>--- a/xen/common/memory.c	Wed Oct 31 09:36:45 2007 +0000
>+++ b/xen/common/memory.c	Wed Oct 31 10:07:42 2007 +0000
>@@ -131,7 +131,8 @@ static void populate_physmap(struct memo
>         if ( unlikely(paging_mode_translate(d)) )
>         {
>             for ( j = 0; j < (1 << a->extent_order); j++ )
>-                guest_physmap_add_page(d, gpfn + j, mfn + j);
>+                if ( guest_physmap_add_page(d, gpfn + j, mfn + j) )
>+                    goto out;
>         }
>         else
>         {
>@@ -445,8 +446,9 @@ static long memory_exchange(XEN_GUEST_HA
>             mfn = page_to_mfn(page);
>             if ( unlikely(paging_mode_translate(d)) )
>             {
>+                /* Ignore failure here. There's nothing we can do. */
>                 for ( k = 0; k < (1UL << exch.out.extent_order); k++ )
>-                    guest_physmap_add_page(d, gpfn + k, mfn + k);
>+                    (void)guest_physmap_add_page(d, gpfn + k, mfn + k);
>             }
>             else
>             {
>diff -r c7d5d229f191 -r 2717128cbdd1 xen/include/asm-x86/p2m.h
>--- a/xen/include/asm-x86/p2m.h	Wed Oct 31 09:36:45 2007 +0000
>+++ b/xen/include/asm-x86/p2m.h	Wed Oct 31 10:07:42 2007 +0000
>@@ -201,14 +201,17 @@ void p2m_teardown(struct domain *d);
> void p2m_teardown(struct domain *d);
> 
> /* Add a page to a domain's p2m table */
>-void guest_physmap_add_entry(struct domain *d, unsigned long gfn,
>+int guest_physmap_add_entry(struct domain *d, unsigned long gfn,
>                              unsigned long mfn, p2m_type_t t);
> 
>-/* Untyped version for RAM only, for compatibility */
>-static inline void guest_physmap_add_page(struct domain *d, unsigned long gfn,
>-                                          unsigned long mfn)
>+/* Untyped version for RAM only, for compatibility 
>+ *
>+ * Return 0 for success
>+ */
>+static inline int guest_physmap_add_page(struct domain *d, unsigned long gfn,
>+                                         unsigned long mfn)
> {
>-    guest_physmap_add_entry(d, gfn, mfn, p2m_ram_rw);
>+    return guest_physmap_add_entry(d, gfn, mfn, p2m_ram_rw);
> }
> 
> /* Remove a page from a domain's p2m table */

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Attachments on bug 316371: 237931 | 239131 | 278811