From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEDD9C64EB8 for ; Thu, 4 Oct 2018 09:34:16 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 499AF213A2 for ; Thu, 4 Oct 2018 09:34:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ozlabs.org header.i=@ozlabs.org header.b="T1NMCAK6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 499AF213A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ozlabs.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42QnlT75BwzF3HC for ; Thu, 4 Oct 2018 19:34:13 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=ozlabs.org header.i=@ozlabs.org header.b="T1NMCAK6"; dkim-atps=neutral Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42QnhT56vwzF3HF for ; Thu, 4 Oct 2018 19:31:37 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=ozlabs.org header.i=@ozlabs.org header.b="T1NMCAK6"; dkim-atps=neutral Received: by ozlabs.org (Postfix) id 42QnhT3zvPz9sB7; Thu, 4 Oct 2018 19:31:37 +1000 (AEST) Received: by ozlabs.org (Postfix, from userid 1003) id 42QnhT355nz9s7W; Thu, 4 Oct 2018 19:31:37 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1538645497; bh=YM6/EiNg6nx3JKF9Lc2egASEzc3KTEZErB4P9Ffd4p4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T1NMCAK69U+fFhx3629eBykhMn3+mXpMdsDJtWRsk0OtTi67Xfx2e8zgw/p82DOGX LQ48o43FgsA7JpFC3i4BXOh+/0HVnS3EN1CB3mHTe7vKh49QSlASyc86bgwai8RfQA LcPkoB3s9c66BIOsKeZJ1n1+V34rEX+4C25h6YATlygf6nb1rKeLu71n5owwlsMESA /GuBGq+w+KGTK3LRENu5gIA6h/R77+Nxct/mXmHVVWvPG+ZJPpkoiYg2wQSWIlKWpx U5RdWRRk0/nN9/oIJXutHsovkF4J+jdRx5oZ86WFwbprtwgFpyYla9Ss1PmSPCAQ1Z +Yw511XQ/LpAA== Date: Thu, 4 Oct 2018 19:21:20 +1000 From: Paul Mackerras To: David Gibson Subject: Re: [PATCH v3 22/33] KVM: PPC: Book3S HV: Handle page fault for a nested guest Message-ID: <20181004092120.GA3255@fergus> References: <1538479892-14835-1-git-send-email-paulus@ozlabs.org> <1538479892-14835-23-git-send-email-paulus@ozlabs.org> <20181003053913.GP1886@umbus.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181003053913.GP1886@umbus.fritz.box> User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Oct 03, 2018 at 03:39:13PM +1000, David Gibson wrote: > On Tue, Oct 02, 2018 at 09:31:21PM +1000, Paul Mackerras wrote: > > From: Suraj Jitindar Singh > > @@ -367,7 +367,9 @@ struct kvmppc_pte { > > bool may_write : 1; > > bool may_execute : 1; > > unsigned long wimg; > > + unsigned long rc; > > u8 page_size; /* MMU_PAGE_xxx */ > > + u16 page_shift; > > It's a bit ugly that this has both page_size and page_shift, which is > redundant information AFAICT. Also, why does page_shift need to be > u16 - given that 2^255 bytes is much more than our supported address > space, let alone a plausible page size. These values are all essentially function outputs, so I don't think it's ugly to have the same information in different forms. I actually don't like using the MMU_PAGE_xxx values, because the information in the mmu_psize_defs[] array depends on the MMU mode of the host, but KVM needs to be able to work with guests in both MMU modes. More generally I don't think it's a good idea that the KVM <-> guest interface depends so much on what the host firmware tells us about the physical machine we're on. Thus I'm trying to move away from using MMU_PSIZE_xxx values and mmu_psize_defs[] in KVM code. I'll change the type to u8. > > diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c > > index bd06a95..ee6f493 100644 > > --- a/arch/powerpc/kvm/book3s_64_mmu_radix.c > > +++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c > > @@ -29,43 +29,16 @@ > > */ > > static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 }; > > > > -/* > > - * Used to walk a partition or process table radix tree in guest memory > > - * Note: We exploit the fact that a partition table and a process > > - * table have the same layout, a partition-scoped page table and a > > - * process-scoped page table have the same layout, and the 2nd > > - * doubleword of a partition table entry has the same layout as > > - * the PTCR register. > > - */ > > -int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr, > > - struct kvmppc_pte *gpte, u64 table, > > - int table_index, u64 *pte_ret_p) > > +int kvmppc_mmu_walk_radix_tree(struct kvm_vcpu *vcpu, gva_t eaddr, > > + struct kvmppc_pte *gpte, u64 root, > > + u64 *pte_ret_p) > > { > > struct kvm *kvm = vcpu->kvm; > > int ret, level, ps; > > - unsigned long ptbl, root; > > - unsigned long rts, bits, offset; > > - unsigned long size, index; > > - struct prtb_entry entry; > > + unsigned long rts, bits, offset, index; > > u64 pte, base, gpa; > > __be64 rpte; > > > > - if ((table & PRTS_MASK) > 24) > > - return -EINVAL; > > - size = 1ul << ((table & PRTS_MASK) + 12); > > - > > - /* Is the table big enough to contain this entry? */ > > - if ((table_index * sizeof(entry)) >= size) > > - return -EINVAL; > > - > > - /* Read the table to find the root of the radix tree */ > > - ptbl = (table & PRTB_MASK) + (table_index * sizeof(entry)); > > - ret = kvm_read_guest(kvm, ptbl, &entry, sizeof(entry)); > > - if (ret) > > - return ret; > > - > > - /* Root is stored in the first double word */ > > - root = be64_to_cpu(entry.prtb0); > > This refactoring somewhat obscures the changes directly relevant to > the nested guest handling. Ideally it would be nice to fold some of > this into the earlier reworkings. True, but given the rapidly approaching merge window, I'm not inclined to rework it. > > + if (ret) { > > + /* We didn't find a pte */ > > + if (ret == -EINVAL) { > > + /* Unsupported mmu config */ > > + flags |= DSISR_UNSUPP_MMU; > > + } else if (ret == -ENOENT) { > > + /* No translation found */ > > + flags |= DSISR_NOHPTE; > > + } else if (ret == -EFAULT) { > > + /* Couldn't access L1 real address */ > > + flags |= DSISR_PRTABLE_FAULT; > > + vcpu->arch.fault_gpa = fault_addr; > > + } else { > > + /* Unknown error */ > > + return ret; > > + } > > + goto resume_host; > > This is effectively forwarding the fault to L1, yes? In which case a > different name might be better than the ambiguous "resume_host". I'll change it to "forward_to_l1". Paul.