1 files changed, 46 insertions, 0 deletions
diff --git a/0026-x86-EPT-correct-special-page-checking-in-epte_get_en.patch b/0026-x86-EPT-correct-special-page-checking-in-epte_get_en.patch
new file mode 100644
index 0000000..c94728a
--- /dev/null
+++ b/0026-x86-EPT-correct-special-page-checking-in-epte_get_en.patch
@@ -0,0 +1,46 @@
+From 6e647efaf2b02ce92bcf80bec47c18cca5084f8a Mon Sep 17 00:00:00 2001
+From: Jan Beulich <jbeulich@suse.com>
+Date: Wed, 26 Jun 2024 13:39:44 +0200
+Subject: [PATCH 26/56] x86/EPT: correct special page checking in
+ epte_get_entry_emt()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+mfn_valid() granularity is (currently) 256Mb. Therefore the start of a
+1Gb page passing the test doesn't necessarily mean all parts of such a
+range would also pass. Yet using the result of mfn_to_page() on an MFN
+which doesn't pass mfn_valid() checking is liable to result in a crash
+(the invocation of mfn_to_page() alone is presumably "just" UB in such a
+case).
+
+Fixes: ca24b2ffdbd9 ("x86/hvm: set 'ipat' in EPT for special pages")
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
+master commit: 5540b94e8191059eb9cbbe98ac316232a42208f6
+master date: 2024-06-13 16:53:34 +0200
+---
+ xen/arch/x86/mm/p2m-ept.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
+index 85c4e8e54f..1aa6bbc771 100644
+--- a/xen/arch/x86/mm/p2m-ept.c
++++ b/xen/arch/x86/mm/p2m-ept.c
+@@ -518,8 +518,12 @@ int epte_get_entry_emt(struct domain *d, gfn_t gfn, mfn_t mfn,
+     }
+ 
+     for ( special_pgs = i = 0; i < (1ul << order); i++ )
+-        if ( is_special_page(mfn_to_page(mfn_add(mfn, i))) )
++    {
++        mfn_t cur = mfn_add(mfn, i);
++
++        if ( mfn_valid(cur) && is_special_page(mfn_to_page(cur)) )
+             special_pgs++;
++    }
+ 
+     if ( special_pgs )
+     {
+-- 
+2.45.2
+