The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From f6ab0107a4942dbf9a5cf0cca3f37e184870a360 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Date: Fri, 7 Feb 2020 09:37:42 -0800
Subject: [PATCH] KVM: x86/mmu: Fix struct guest_walker arrays for 5-level
paging
Define PT_MAX_FULL_LEVELS as PT64_ROOT_MAX_LEVEL, i.e. 5, to fix shadow
paging for 5-level guest page tables. PT_MAX_FULL_LEVELS is used to
size the arrays that track guest pages table information, i.e. using a
"max levels" of 4 causes KVM to access garbage beyond the end of an
array when querying state for level 5 entries. E.g. FNAME(gpte_changed)
will read garbage and most likely return %true for a level 5 entry,
soft-hanging the guest because FNAME(fetch) will restart the guest
instead of creating SPTEs because it thinks the guest PTE has changed.
Note, KVM doesn't yet support 5-level nested EPT, so PT_MAX_FULL_LEVELS
gets to stay "4" for the PTTYPE_EPT case.
Fixes: 855feb673640 ("KVM: MMU: Add 5 level EPT & Shadow page table support.")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 4e1ef0473663..e4c8a4cbf407 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -33,7 +33,7 @@
#define PT_GUEST_ACCESSED_SHIFT PT_ACCESSED_SHIFT
#define PT_HAVE_ACCESSED_DIRTY(mmu) true
#ifdef CONFIG_X86_64
- #define PT_MAX_FULL_LEVELS 4
+ #define PT_MAX_FULL_LEVELS PT64_ROOT_MAX_LEVEL
#define CMPXCHG cmpxchg
#else
#define CMPXCHG cmpxchg64
