From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) (using TLSv1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 59E8714009A for ; Thu, 8 May 2014 20:12:35 +1000 (EST) Message-ID: <536B5890.1090806@suse.de> Date: Thu, 08 May 2014 12:12:32 +0200 From: Alexander Graf MIME-Version: 1.0 To: "Aneesh Kumar K.V" Subject: Re: [PATCH V2] KVM: PPC: BOOK3S: HV: Add mixed page-size support for guest References: <1399399296-17711-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1399399296-17711-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: paulus@samba.org, linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 05/06/2014 08:01 PM, Aneesh Kumar K.V wrote: > On recent IBM Power CPUs, while the hashed page table is looked up using > the page size from the segmentation hardware (i.e. the SLB), it is > possible to have the HPT entry indicate a larger page size. Thus for > example it is possible to put a 16MB page in a 64kB segment, but since > the hash lookup is done using a 64kB page size, it may be necessary to > put multiple entries in the HPT for a single 16MB page. This > capability is called mixed page-size segment (MPSS). With MPSS, > there are two relevant page sizes: the base page size, which is the > size used in searching the HPT, and the actual page size, which is the > size indicated in the HPT entry. [ Note that the actual page size is > always >= base page size ]. > > We use "ibm,segment-page-sizes" device tree node to advertise > the MPSS support to PAPR guest. The penc encoding indicates whether > we support a specific combination of base page size and actual > page size in the same segment. We also use the penc value in the > LP encoding of HPTE entry. > > This patch exposes MPSS support to KVM guest by advertising the > feature via "ibm,segment-page-sizes". It also adds the necessary changes > to decode the base page size and the actual page size correctly from the > HPTE entry. > > Signed-off-by: Aneesh Kumar K.V Thanks, applied to kvm-ppc-queue. Alex