Re: [bisected] KVM in 3.19-rc1 is completely broken

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2014/12/24 5:29, Andy Lutomirski wrote:
> On Tue, Dec 23, 2014 at 1:13 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>>> I can reproduce it using the same steps on a Sandy Bridge laptop, with
>>> whatever QEMU is packaged in Fedora 21.  I attached the config.
>>>
>>> I also submitted a virtme update for Fedora Rawhide and 21 (20 is
>>> still building) in case it helps.  The build is here:
>>>
>>> http://koji.fedoraproject.org/koji/buildinfo?buildID=600732
>>
>> The other reporter bisected it to
>> 0e60b0799fedc495a5c57dbd669de3c10d72edd2.  Can you try its parent?
>
> That's what I bisected it to.  The parent works.
>
>>
>> Also, does it break with 3.18 host and 3.19-rc1 guest, or with
>> 3.19-rc1 host and 3.18 guest?  (Sorry I should do this myself
>> but I'm a bit swamped due to vacation until Jan 6th).
>>
>
> The breakage is with 3.17.7-something L0 and the same test kernel as
> L1 and L2.  I think it breaks the same way with 3.19-rc1 as host and
> guest without any nesting, but that's awkward to test right now.
>


Andy,

Could you try this?

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
  virt/kvm/kvm_main.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f528343..a2d928c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -672,6 +672,7 @@ static void update_memslots(struct kvm_memslots *slots,
         WARN_ON(mslots[i].id != id);
         if (!new->npages) {
                 new->base_gfn = 0;
+               new->flags = 0;
                 if (mslots[i].npages)
                         slots->used_slots--;
         } else {
@@ -688,7 +689,7 @@ static void update_memslots(struct kvm_memslots *slots,
                 i++;
         }
         while (i > 0 &&
-              new->base_gfn > mslots[i - 1].base_gfn) {
+              new->base_gfn >= mslots[i - 1].base_gfn) {
                 mslots[i] = mslots[i - 1];
                 slots->id_to_index[mslots[i].id] = i;
                 i--;
-- 
1.9.1

Tiejun