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Date: Thu, 6 Jun 2024 09:50:57 -0500
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Reply-To: babu.moger@amd.com
Subject: Re: [PATCH] KVM: Fix Undefined Behavior Sanitizer(UBSAN) error
To: Sean Christopherson <seanjc@google.com>,
 Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <98ad0dab3a2c66834e50e6d465dcae47dd80758b.1717436464.git.babu.moger@amd.com>
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From: "Moger, Babu" <babu.moger@amd.com>
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On 6/3/24 15:38, Sean Christopherson wrote:
> On Mon, Jun 03, 2024, Paolo Bonzini wrote:
>> On Mon, Jun 3, 2024 at 7:54 PM Sean Christopherson <seanjc@google.com> wrote:
>>>> However, VM boots up fine without any issues and operational.
>>
>> Yes, the caller uses kvm_handle_hva_range() as if it returned void.
>>
>>> Ah, the "break" will only break out of the memslot loop, it won't break out of
>>> the address space loop.  Stupid SMM.
>>>
>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>>> index b312d0cbe60b..70f5a39f8302 100644
>>> --- a/virt/kvm/kvm_main.c
>>> +++ b/virt/kvm/kvm_main.c
>>> @@ -651,7 +651,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
>>>                                         range->on_lock(kvm);
>>>
>>>                                 if (IS_KVM_NULL_FN(range->handler))
>>> -                                       break;
>>> +                                       goto mmu_unlock;
>>>                         }
>>>                         r.ret |= range->handler(kvm, &gfn_range);
>>>                 }
>>> @@ -660,6 +660,7 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
>>>         if (range->flush_on_ret && r.ret)
>>>                 kvm_flush_remote_tlbs(kvm);
>>>
>>> +mmu_unlock:
>>>         if (r.found_memslot)
>>>                 KVM_MMU_UNLOCK(kvm);
>>
>> Yep. If you want to just reply with Signed-off-by I'll mix the
>> original commit message and your patch.
> 
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Thanks Sean, Paolo.

I will send v2 with Sean's patch.
-- 
Thanks
Babu Moger