From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Ehrhardt Date: Mon, 11 Aug 2008 08:33:10 +0000 Subject: Re: [PATCH 4 of 5] kvm: ppc: Write only modified shadow entries into Message-Id: <489FF946.3020409@linux.vnet.ibm.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: kvm-ppc@vger.kernel.org Liu Yu wrote: > > =20 >> -----Original Message----- >> From: kvm-ppc-owner@vger.kernel.org=20 >> [mailto:kvm-ppc-owner@vger.kernel.org] On Behalf Of Hollis Blanchard >> Sent: Saturday, July 26, 2008 2:55 AM >> To: avi@qumranet.com >> Cc: kvm-ppc@vger.kernel.org; kvm@vger.kernel.org >> Subject: [PATCH 4 of 5] kvm: ppc: Write only modified shadow=20 >> entries into theTLB on exit >> >> @@ -229,6 +235,7 @@ void kvmppc_mmu_priv_switch(struct kvm_v >> =20 >> kvmppc_44x_shadow_release(vcpu, i); >> stlbe->word0 =3D 0; >> + kvmppc_tlbe_set_modified(vcpu, i); >> KVMTRACE_5D(STLB_INVAL, vcpu, i, >> stlbe->tid, stlbe->word0, stlbe->word1, >> stlbe->word2, handler); >> =20 > > Can this place use "_tlbia()" instead? > =20 Hi Liu, when we exit&reenter a guest on the lightweight path this patch saves us=20 from rebuilding too much of the tlb. It's just the point of the patch to not invalidate all tlb entries on=20 every exit, but keeping as much as possible. Additionally I'm not even sure if tlbia is available on all cores used. Am I overlooking something ? - what do you think would be the benefit of=20 using _tlbia() here? Do you mean the loop to clear up to the hwater mark where this patch=20 makes changes and not this patch itself? --=20 Gr=FCsse / regards,=20 Christian Ehrhardt IBM Linux Technology Center, Open Virtualization