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=-11.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 F04FDC433E0 for ; Wed, 22 Jul 2020 04:57:33 +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 98033207BB for ; Wed, 22 Jul 2020 04:57:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="XhBTf2Xl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 98033207BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BBNVz4xWszDqv5 for ; Wed, 22 Jul 2020 14:57:31 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BBN424fXSzDqW1 for ; Wed, 22 Jul 2020 14:37:38 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=XhBTf2Xl; dkim-atps=neutral Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4BBN4054f5z9sPB; Wed, 22 Jul 2020 14:37:36 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1595392657; bh=fM9hNVHywyNvJcSx2b2kKXg/Co8o/eplCDBvPFYZHtQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=XhBTf2XlQ0iKuM8F4btdqyKRiqoAh5JEXAa7jBHCsbdRy+4eTu6e1q8pe79E6XJki Q/TN5/ydocEu1m4EEoNgKUd9tAmOSQc4PPZwqW8+hv7gqp43NkdJyFTGCbS2Qr3I4c 7EOxyaTD4uD64rfHgdlktQajoGg778+POQBDZx3Kt51EE5WFKL1m8RMWsk2At2aWRv 8zdfQ68VjTdeSRmXrbleJrVQ+nQoCemYNme4b0WsUUz4wdTV7TvQLz0qCn9HjyeI01 e32qYRMe6GOq9FEpD1zFcWKMxHXYgkgccgxJRnOxh+2UQQmU65uOxvbzpXLF+CoVgx UF9suj/wvmiYw== From: Michael Ellerman To: Athira Rajeev , Paul Mackerras Subject: Re: [v3 02/15] KVM: PPC: Book3S HV: Cleanup updates for kvm vcpu MMCR In-Reply-To: References: <1594996707-3727-1-git-send-email-atrajeev@linux.vnet.ibm.com> <1594996707-3727-3-git-send-email-atrajeev@linux.vnet.ibm.com> <20200721035420.GA3819606@thinks.paulus.ozlabs.org> Date: Wed, 22 Jul 2020 14:37:35 +1000 Message-ID: <87y2ncqi5s.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: ego@linux.vnet.ibm.com, Michael Neuling , maddy@linux.vnet.ibm.com, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, svaidyan@in.ibm.com, acme@kernel.org, jolsa@kernel.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Athira Rajeev writes: >> On 21-Jul-2020, at 9:24 AM, Paul Mackerras wrote: >> On Fri, Jul 17, 2020 at 10:38:14AM -0400, Athira Rajeev wrote: >>> Currently `kvm_vcpu_arch` stores all Monitor Mode Control registers >>> in a flat array in order: mmcr0, mmcr1, mmcra, mmcr2, mmcrs >>> Split this to give mmcra and mmcrs its own entries in vcpu and >>> use a flat array for mmcr0 to mmcr2. This patch implements this >>> cleanup to make code easier to read. >>=20 >> Changing the way KVM stores these values internally is fine, but >> changing the user ABI is not. This part: >>=20 >>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include= /uapi/asm/kvm.h >>> index 264e266..e55d847 100644 >>> --- a/arch/powerpc/include/uapi/asm/kvm.h >>> +++ b/arch/powerpc/include/uapi/asm/kvm.h >>> @@ -510,8 +510,8 @@ struct kvm_ppc_cpu_char { >>>=20 >>> #define KVM_REG_PPC_MMCR0 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x10) >>> #define KVM_REG_PPC_MMCR1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x11) >>> -#define KVM_REG_PPC_MMCRA (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x12) >>> -#define KVM_REG_PPC_MMCR2 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x13) >>> +#define KVM_REG_PPC_MMCR2 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x12) >>> +#define KVM_REG_PPC_MMCRA (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x13) >>=20 >> means that existing userspace programs that used to work would now be >> broken. That is not acceptable (breaking the user ABI is only ever >> acceptable with a very compelling reason). So NAK to this part of the >> patch. > > Hi Paul > > Thanks for checking the patch. I understood your point on user ABI breaka= ge that this particular change can cause. > I will retain original KVM_REG_PPC_MMCRA and KVM_REG_PPC_MMCR2 order in `= kvm.h` > And with that, additionally I will need below change ( on top of current = patch ) for my clean up updates for kvm cpu MMCR to work, > Because now mmcra and mmcrs will have its own entries in vcpu and is not = part of the mmcr[] array > Please suggest if this looks good I did the same patch I think in my testing branch, it's here: https://github.com/linuxppc/linux/commit/daea78154eff1b7e2f36be05a8f95feb5a= 588912 Can you please check that matches what you sent. cheers > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index 3f90eee261fc..b10bb404f0d5 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -1679,10 +1679,13 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu = *vcpu, u64 id, > case KVM_REG_PPC_UAMOR: > *val =3D get_reg_val(id, vcpu->arch.uamor); > break; > - case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR2: > + case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR1: > i =3D id - KVM_REG_PPC_MMCR0; > *val =3D get_reg_val(id, vcpu->arch.mmcr[i]); > break; > + case KVM_REG_PPC_MMCR2: > + *val =3D get_reg_val(id, vcpu->arch.mmcr[2]); > + break; > case KVM_REG_PPC_MMCRA: > *val =3D get_reg_val(id, vcpu->arch.mmcra); > break; > @@ -1906,10 +1909,13 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu = *vcpu, u64 id, > case KVM_REG_PPC_UAMOR: > vcpu->arch.uamor =3D set_reg_val(id, *val); > break; > - case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR2: > + case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR1: > i =3D id - KVM_REG_PPC_MMCR0; > vcpu->arch.mmcr[i] =3D set_reg_val(id, *val); > break; > + case KVM_REG_PPC_MMCR2: > + vcpu->arch.mmcr[2] =3D set_reg_val(id, *val); > + break; > case KVM_REG_PPC_MMCRA: > vcpu->arch.mmcra =3D set_reg_val(id, *val); > break; > =E2=80=94 > > >>=20 >> Regards, >> Paul.