releases/2.6.28.10/kvm-mmu-extend-kvm_mmu_page-slot_bitmap-size.patch

From mtosatti@redhat.com  Tue Apr 28 21:36:00 2009
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Mon, 23 Mar 2009 17:51:20 -0300
Subject: KVM: MMU: Extend kvm_mmu_page->slot_bitmap size
To: stable@kernel.org
Cc: mtosatti@redhat.com, avi@redhat.com, Sheng Yang <sheng@linux.intel.com>
Message-ID: <1237841498-14100-4-git-send-email-mtosatti@redhat.com>


From: Sheng Yang <sheng@linux.intel.com>

(cherry picked from 291f26bc0f89518ad7ee3207c09eb8a743ac8fcc)

Otherwise set_bit() for private memory slot(above KVM_MEMORY_SLOTS) would
corrupted memory in 32bit host.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 arch/x86/include/asm/kvm_host.h |    8 +++++---
 arch/x86/kvm/mmu.c              |    6 +++---
 2 files changed, 8 insertions(+), 6 deletions(-)

--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -190,9 +190,11 @@ struct kvm_mmu_page {
 	u64 *spt;
 	/* hold the gfn of each spte inside spt */
 	gfn_t *gfns;
-	unsigned long slot_bitmap; /* One bit set per slot which has memory
-				    * in this shadow page.
-				    */
+	/*
+	 * One bit set per slot which has memory
+	 * in this shadow page.
+	 */
+	DECLARE_BITMAP(slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
 	int multimapped;         /* More than one parent_pte? */
 	int root_count;          /* Currently serving as active root */
 	bool unsync;
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -787,7 +787,7 @@ static struct kvm_mmu_page *kvm_mmu_allo
 	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 	list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 	ASSERT(is_empty_shadow_page(sp->spt));
-	sp->slot_bitmap = 0;
+	bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
 	sp->multimapped = 0;
 	sp->parent_pte = parent_pte;
 	--vcpu->kvm->arch.n_free_mmu_pages;
@@ -1362,7 +1362,7 @@ static void page_header_update_slot(stru
 	int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
 	struct kvm_mmu_page *sp = page_header(__pa(pte));
 
-	__set_bit(slot, &sp->slot_bitmap);
+	__set_bit(slot, sp->slot_bitmap);
 }
 
 static void mmu_convert_notrap(struct kvm_mmu_page *sp)
@@ -2451,7 +2451,7 @@ void kvm_mmu_slot_remove_write_access(st
 		int i;
 		u64 *pt;
 
-		if (!test_bit(slot, &sp->slot_bitmap))
+		if (!test_bit(slot, sp->slot_bitmap))
 			continue;
 
 		pt = sp->spt;