Patch "KVM: do not bias the generation number in kvm_current_mmio_generation" has been added to the 3.16-stable tree

[g***@linuxfoundation.org]

This is a note to let you know that I've just added the patch titled

KVM: do not bias the generation number in kvm_current_mmio_generation

to the 3.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
kvm-do-not-bias-the-generation-number-in-kvm_current_mmio_generation.patch
and it can be found in the queue-3.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,

From 00f034a12fdd81210d58116326d92780aac5c238 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <***@redhat.com>
Date: Wed, 20 Aug 2014 14:29:21 +0200
Subject: KVM: do not bias the generation number in kvm_current_mmio_generation

From: Paolo Bonzini <***@redhat.com>

commit 00f034a12fdd81210d58116326d92780aac5c238 upstream.

The next patch will give a meaning (a la seqcount) to the low bit of the
generation number. Ensure that it matches between kvm->memslots->generation
and kvm_current_mmio_generation().

Reviewed-by: David Matlack <***@google.com>
Reviewed-by: Xiao Guangrong <***@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <***@redhat.com>
Signed-off-by: Greg Kroah-Hartman <***@linuxfoundation.org>

---
arch/x86/kvm/mmu.c | 7 +------
virt/kvm/kvm_main.c | 7 +++++++
2 files changed, 8 insertions(+), 6 deletions(-)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -240,12 +240,7 @@ static unsigned int get_mmio_spte_genera

static unsigned int kvm_current_mmio_generation(struct kvm *kvm)
{
- /*
- * Init kvm generation close to MMIO_MAX_GEN to easily test the
- * code of handling generation number wrap-around.
- */
- return (kvm_memslots(kvm)->generation +
- MMIO_MAX_GEN - 150) & MMIO_GEN_MASK;
+ return kvm_memslots(kvm)->generation & MMIO_GEN_MASK;
}

static void mark_mmio_spte(struct kvm *kvm, u64 *sptep, u64 gfn,
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -472,6 +472,13 @@ static struct kvm *kvm_create_vm(unsigne
kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
if (!kvm->memslots)
goto out_err_no_srcu;
+
+ /*
+ * Init kvm generation close to the maximum to easily test the
+ * code of handling generation number wrap-around.
+ */
+ kvm->memslots->generation = -150;
+
kvm_init_memslots_id(kvm);
if (init_srcu_struct(&kvm->srcu))
goto out_err_no_srcu;


Patches currently in stable-queue which might be from ***@redhat.com are

queue-3.16/kvm-x86-fix-stale-mmio-cache-bug.patch
queue-3.16/x86-kvm-vmx-preserve-cr4-across-vm-entry.patch
queue-3.16/kvm-don-t-take-vcpu-mutex-for-obviously-invalid-vcpu-ioctls.patch
queue-3.16/kvm-do-not-bias-the-generation-number-in-kvm_current_mmio_generation.patch
queue-3.16/kvm-fix-potentially-corrupt-mmio-cache.patch