From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Hogan Subject: Re: [PATCH v3 6/9] MIPS: KVM: Restore correct value for WIRED at TLB uninit Date: Wed, 25 Jun 2014 10:24:36 +0100 Message-ID: <53AA9554.1050908@imgtec.com> References: <1403631071-6012-1-git-send-email-dengcheng.zhu@imgtec.com> <1403631071-6012-7-git-send-email-dengcheng.zhu@imgtec.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: , , , , To: Deng-Cheng Zhu , Return-path: Received: from mailapp01.imgtec.com ([195.59.15.196]:64652 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752771AbaFYJYj (ORCPT ); Wed, 25 Jun 2014 05:24:39 -0400 In-Reply-To: <1403631071-6012-7-git-send-email-dengcheng.zhu@imgtec.com> Sender: kvm-owner@vger.kernel.org List-ID: On 24/06/14 18:31, Deng-Cheng Zhu wrote: > From: Deng-Cheng Zhu > > At TLB initialization, the commpage TLB entry is reserved on top of the > existing WIRED entries (the number not necessarily be 0). > > Signed-off-by: Deng-Cheng Zhu > --- > arch/mips/kvm/mips.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c > index 27250ee..3d53d34 100644 > --- a/arch/mips/kvm/mips.c > +++ b/arch/mips/kvm/mips.c > @@ -170,7 +170,7 @@ void kvm_arch_sync_events(struct kvm *kvm) > static void kvm_mips_uninit_tlbs(void *arg) > { > /* Restore wired count */ > - write_c0_wired(0); > + write_c0_wired(read_c0_wired() - 1); > mtc0_tlbw_hazard(); > /* Clear out all the TLBs */ > kvm_local_flush_tlb_all(); kvm_local_flush_tlb_all blasts all the entries away regardless of wired, so I don't think this is an improvement. I suspect to really be safe/correct in the presence of other dynamic users of wired it would have to either manage arbitrary allocation/deallocation of per-cpu tlb entries correctly from a single place, or abandon the use of wired altogether. Cheers James