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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 D1850C3279B for ; Wed, 4 Jul 2018 22:03:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7309D216F9 for ; Wed, 4 Jul 2018 22:03:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7309D216F9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752976AbeGDWCx (ORCPT ); Wed, 4 Jul 2018 18:02:53 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:43086 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752844AbeGDWCv (ORCPT ); Wed, 4 Jul 2018 18:02:51 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DC39418A; Wed, 4 Jul 2018 15:02:50 -0700 (PDT) Received: from [10.37.10.44] (unknown [10.37.10.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5BFB03F5A0; Wed, 4 Jul 2018 15:02:47 -0700 (PDT) Subject: Re: [PATCH v3 15/20] kvm: arm/arm64: Allow tuning the physical address size for VM To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, marc.zyngier@arm.com, cdall@kernel.org, eric.auger@redhat.com, julien.grall@arm.com, catalin.marinas@arm.com, punit.agrawal@arm.com, qemu-devel@nongnu.org, Peter Maydel , Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= References: <1530270944-11351-1-git-send-email-suzuki.poulose@arm.com> <1530270944-11351-16-git-send-email-suzuki.poulose@arm.com> <20180704155104.GN4828@arm.com> From: Suzuki K Poulose Message-ID: <12d1832a-1a13-7dd4-662b-addf58400789@arm.com> Date: Wed, 4 Jul 2018 23:03:10 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180704155104.GN4828@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/04/2018 04:51 PM, Will Deacon wrote: > Hi Suzuki, > > On Fri, Jun 29, 2018 at 12:15:35PM +0100, Suzuki K Poulose wrote: >> Allow specifying the physical address size for a new VM via >> the kvm_type argument for KVM_CREATE_VM ioctl. This allows >> us to finalise the stage2 page table format as early as possible >> and hence perform the right checks on the memory slots without >> complication. The size is encoded as Log2(PA_Size) in the bits[7:0] >> of the type field and can encode more information in the future if >> required. The IPA size is still capped at 40bits. >> >> Cc: Marc Zyngier >> Cc: Christoffer Dall >> Cc: Peter Maydel >> Cc: Paolo Bonzini >> Cc: Radim Krčmář >> Signed-off-by: Suzuki K Poulose >> --- >> arch/arm/include/asm/kvm_mmu.h | 2 ++ >> arch/arm64/include/asm/kvm_arm.h | 10 +++------- >> arch/arm64/include/asm/kvm_mmu.h | 2 ++ >> include/uapi/linux/kvm.h | 10 ++++++++++ >> virt/kvm/arm/arm.c | 24 ++++++++++++++++++++++-- >> 5 files changed, 39 insertions(+), 9 deletions(-) > > [...] > >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 4df9bb6..fa4cab0 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -751,6 +751,16 @@ struct kvm_ppc_resize_hpt { >> #define KVM_S390_SIE_PAGE_OFFSET 1 >> >> /* >> + * On arm/arm64, machine type can be used to request the physical >> + * address size for the VM. Bits [7-0] have been reserved for the >> + * PA size shift (i.e, log2(PA_Size)). For backward compatibility, >> + * value 0 implies the default IPA size, which is 40bits. >> + */ >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK 0xff >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT(x) \ >> + ((x) & KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK) > > This seems like you're allocating quite a lot of bits in a non-extensible > interface to a fairly esoteric parameter. Would it be better to add another > ioctl, or condense the number of sizes you support instead? As I explained in the other thread, we need the size as soon as the VM is created. The major challenge is keeping the backward compatibility by mapping 0 to 40bits. I will give it a thought. Suzuki From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suzuki K Poulose Subject: Re: [PATCH v3 15/20] kvm: arm/arm64: Allow tuning the physical address size for VM Date: Wed, 4 Jul 2018 23:03:10 +0100 Message-ID: <12d1832a-1a13-7dd4-662b-addf58400789@arm.com> References: <1530270944-11351-1-git-send-email-suzuki.poulose@arm.com> <1530270944-11351-16-git-send-email-suzuki.poulose@arm.com> <20180704155104.GN4828@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; Format="flowed" Content-Transfer-Encoding: base64 Cc: Peter Maydel , cdall@kernel.org, kvm@vger.kernel.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , marc.zyngier@arm.com, catalin.marinas@arm.com, punit.agrawal@arm.com, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, eric.auger@redhat.com, julien.grall@arm.com, james.morse@arm.com, Paolo Bonzini , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org To: Will Deacon Return-path: In-Reply-To: <20180704155104.GN4828@arm.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: kvm.vger.kernel.org T24gMDcvMDQvMjAxOCAwNDo1MSBQTSwgV2lsbCBEZWFjb24gd3JvdGU6Cj4gSGkgU3V6dWtpLAo+ IAo+IE9uIEZyaSwgSnVuIDI5LCAyMDE4IGF0IDEyOjE1OjM1UE0gKzAxMDAsIFN1enVraSBLIFBv dWxvc2Ugd3JvdGU6Cj4+IEFsbG93IHNwZWNpZnlpbmcgdGhlIHBoeXNpY2FsIGFkZHJlc3Mgc2l6 ZSBmb3IgYSBuZXcgVk0gdmlhCj4+IHRoZSBrdm1fdHlwZSBhcmd1bWVudCBmb3IgS1ZNX0NSRUFU RV9WTSBpb2N0bC4gVGhpcyBhbGxvd3MKPj4gdXMgdG8gZmluYWxpc2UgdGhlIHN0YWdlMiBwYWdl IHRhYmxlIGZvcm1hdCBhcyBlYXJseSBhcyBwb3NzaWJsZQo+PiBhbmQgaGVuY2UgcGVyZm9ybSB0 aGUgcmlnaHQgY2hlY2tzIG9uIHRoZSBtZW1vcnkgc2xvdHMgd2l0aG91dAo+PiBjb21wbGljYXRp b24uIFRoZSBzaXplIGlzIGVuY29kZWQgYXMgTG9nMihQQV9TaXplKSBpbiB0aGUgYml0c1s3OjBd Cj4+IG9mIHRoZSB0eXBlIGZpZWxkIGFuZCBjYW4gZW5jb2RlIG1vcmUgaW5mb3JtYXRpb24gaW4g dGhlIGZ1dHVyZSBpZgo+PiByZXF1aXJlZC4gVGhlIElQQSBzaXplIGlzIHN0aWxsIGNhcHBlZCBh dCA0MGJpdHMuCj4+Cj4+IENjOiBNYXJjIFp5bmdpZXIgPG1hcmMuenluZ2llckBhcm0uY29tPgo+ PiBDYzogQ2hyaXN0b2ZmZXIgRGFsbCA8Y2RhbGxAa2VybmVsLm9yZz4KPj4gQ2M6IFBldGVyIE1h eWRlbCA8cGV0ZXIubWF5ZGVsbEBsaW5hcm8ub3JnPgo+PiBDYzogUGFvbG8gQm9uemluaSA8cGJv bnppbmlAcmVkaGF0LmNvbT4KPj4gQ2M6IFJhZGltIEtyxI1tw6HFmSA8cmtyY21hckByZWRoYXQu Y29tPgo+PiBTaWduZWQtb2ZmLWJ5OiBTdXp1a2kgSyBQb3Vsb3NlIDxzdXp1a2kucG91bG9zZUBh cm0uY29tPgo+PiAtLS0KPj4gICBhcmNoL2FybS9pbmNsdWRlL2FzbS9rdm1fbW11LmggICB8ICAy ICsrCj4+ICAgYXJjaC9hcm02NC9pbmNsdWRlL2FzbS9rdm1fYXJtLmggfCAxMCArKystLS0tLS0t Cj4+ICAgYXJjaC9hcm02NC9pbmNsdWRlL2FzbS9rdm1fbW11LmggfCAgMiArKwo+PiAgIGluY2x1 ZGUvdWFwaS9saW51eC9rdm0uaCAgICAgICAgIHwgMTAgKysrKysrKysrKwo+PiAgIHZpcnQva3Zt L2FybS9hcm0uYyAgICAgICAgICAgICAgIHwgMjQgKysrKysrKysrKysrKysrKysrKysrKy0tCj4+ ICAgNSBmaWxlcyBjaGFuZ2VkLCAzOSBpbnNlcnRpb25zKCspLCA5IGRlbGV0aW9ucygtKQo+IAo+ IFsuLi5dCj4gCj4+IGRpZmYgLS1naXQgYS9pbmNsdWRlL3VhcGkvbGludXgva3ZtLmggYi9pbmNs dWRlL3VhcGkvbGludXgva3ZtLmgKPj4gaW5kZXggNGRmOWJiNi4uZmE0Y2FiMCAxMDA2NDQKPj4g LS0tIGEvaW5jbHVkZS91YXBpL2xpbnV4L2t2bS5oCj4+ICsrKyBiL2luY2x1ZGUvdWFwaS9saW51 eC9rdm0uaAo+PiBAQCAtNzUxLDYgKzc1MSwxNiBAQCBzdHJ1Y3Qga3ZtX3BwY19yZXNpemVfaHB0 IHsKPj4gICAjZGVmaW5lIEtWTV9TMzkwX1NJRV9QQUdFX09GRlNFVCAxCj4+ICAgCj4+ICAgLyoK Pj4gKyAqIE9uIGFybS9hcm02NCwgbWFjaGluZSB0eXBlIGNhbiBiZSB1c2VkIHRvIHJlcXVlc3Qg dGhlIHBoeXNpY2FsCj4+ICsgKiBhZGRyZXNzIHNpemUgZm9yIHRoZSBWTS4gQml0cyBbNy0wXSBo YXZlIGJlZW4gcmVzZXJ2ZWQgZm9yIHRoZQo+PiArICogUEEgc2l6ZSBzaGlmdCAoaS5lLCBsb2cy KFBBX1NpemUpKS4gRm9yIGJhY2t3YXJkIGNvbXBhdGliaWxpdHksCj4+ICsgKiB2YWx1ZSAwIGlt cGxpZXMgdGhlIGRlZmF1bHQgSVBBIHNpemUsIHdoaWNoIGlzIDQwYml0cy4KPj4gKyAqLwo+PiAr I2RlZmluZSBLVk1fVk1fVFlQRV9BUk1fUEhZU19TSElGVF9NQVNLCTB4ZmYKPj4gKyNkZWZpbmUg S1ZNX1ZNX1RZUEVfQVJNX1BIWVNfU0hJRlQoeCkJCVwKPj4gKwkoKHgpICYgS1ZNX1ZNX1RZUEVf QVJNX1BIWVNfU0hJRlRfTUFTSykKPiAKPiBUaGlzIHNlZW1zIGxpa2UgeW91J3JlIGFsbG9jYXRp bmcgcXVpdGUgYSBsb3Qgb2YgYml0cyBpbiBhIG5vbi1leHRlbnNpYmxlCj4gaW50ZXJmYWNlIHRv IGEgZmFpcmx5IGVzb3RlcmljIHBhcmFtZXRlci4gV291bGQgaXQgYmUgYmV0dGVyIHRvIGFkZCBh bm90aGVyCj4gaW9jdGwsIG9yIGNvbmRlbnNlIHRoZSBudW1iZXIgb2Ygc2l6ZXMgeW91IHN1cHBv cnQgaW5zdGVhZD8KCkFzIEkgZXhwbGFpbmVkIGluIHRoZSBvdGhlciB0aHJlYWQsIHdlIG5lZWQg dGhlIHNpemUgYXMgc29vbiBhcyB0aGUgVk0KaXMgY3JlYXRlZC4gVGhlIG1ham9yIGNoYWxsZW5n ZSBpcyBrZWVwaW5nIHRoZSBiYWNrd2FyZCBjb21wYXRpYmlsaXR5IGJ5Cm1hcHBpbmcgMCB0byA0 MGJpdHMuIEkgd2lsbCBnaXZlIGl0IGEgdGhvdWdodC4KClN1enVraQoKX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5n IGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5p bmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgtYXJtLWtlcm5lbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1faprV-0004xg-Gl for qemu-devel@nongnu.org; Wed, 04 Jul 2018 18:02:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1faprQ-0007QM-Vh for qemu-devel@nongnu.org; Wed, 04 Jul 2018 18:02:57 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50544 helo=foss.arm.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1faprQ-0007Po-Ob for qemu-devel@nongnu.org; Wed, 04 Jul 2018 18:02:52 -0400 References: <1530270944-11351-1-git-send-email-suzuki.poulose@arm.com> <1530270944-11351-16-git-send-email-suzuki.poulose@arm.com> <20180704155104.GN4828@arm.com> From: Suzuki K Poulose Message-ID: <12d1832a-1a13-7dd4-662b-addf58400789@arm.com> Date: Wed, 4 Jul 2018 23:03:10 +0100 MIME-Version: 1.0 In-Reply-To: <20180704155104.GN4828@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 15/20] kvm: arm/arm64: Allow tuning the physical address size for VM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, james.morse@arm.com, marc.zyngier@arm.com, cdall@kernel.org, eric.auger@redhat.com, julien.grall@arm.com, catalin.marinas@arm.com, punit.agrawal@arm.com, qemu-devel@nongnu.org, Peter Maydel , Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= On 07/04/2018 04:51 PM, Will Deacon wrote: > Hi Suzuki, >=20 > On Fri, Jun 29, 2018 at 12:15:35PM +0100, Suzuki K Poulose wrote: >> Allow specifying the physical address size for a new VM via >> the kvm_type argument for KVM_CREATE_VM ioctl. This allows >> us to finalise the stage2 page table format as early as possible >> and hence perform the right checks on the memory slots without >> complication. The size is encoded as Log2(PA_Size) in the bits[7:0] >> of the type field and can encode more information in the future if >> required. The IPA size is still capped at 40bits. >> >> Cc: Marc Zyngier >> Cc: Christoffer Dall >> Cc: Peter Maydel >> Cc: Paolo Bonzini >> Cc: Radim Kr=C4=8Dm=C3=A1=C5=99 >> Signed-off-by: Suzuki K Poulose >> --- >> arch/arm/include/asm/kvm_mmu.h | 2 ++ >> arch/arm64/include/asm/kvm_arm.h | 10 +++------- >> arch/arm64/include/asm/kvm_mmu.h | 2 ++ >> include/uapi/linux/kvm.h | 10 ++++++++++ >> virt/kvm/arm/arm.c | 24 ++++++++++++++++++++++-- >> 5 files changed, 39 insertions(+), 9 deletions(-) >=20 > [...] >=20 >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 4df9bb6..fa4cab0 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -751,6 +751,16 @@ struct kvm_ppc_resize_hpt { >> #define KVM_S390_SIE_PAGE_OFFSET 1 >> =20 >> /* >> + * On arm/arm64, machine type can be used to request the physical >> + * address size for the VM. Bits [7-0] have been reserved for the >> + * PA size shift (i.e, log2(PA_Size)). For backward compatibility, >> + * value 0 implies the default IPA size, which is 40bits. >> + */ >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK 0xff >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT(x) \ >> + ((x) & KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK) >=20 > This seems like you're allocating quite a lot of bits in a non-extensib= le > interface to a fairly esoteric parameter. Would it be better to add ano= ther > ioctl, or condense the number of sizes you support instead? As I explained in the other thread, we need the size as soon as the VM is created. The major challenge is keeping the backward compatibility by mapping 0 to 40bits. I will give it a thought. Suzuki From mboxrd@z Thu Jan 1 00:00:00 1970 From: suzuki.poulose@arm.com (Suzuki K Poulose) Date: Wed, 4 Jul 2018 23:03:10 +0100 Subject: [PATCH v3 15/20] kvm: arm/arm64: Allow tuning the physical address size for VM In-Reply-To: <20180704155104.GN4828@arm.com> References: <1530270944-11351-1-git-send-email-suzuki.poulose@arm.com> <1530270944-11351-16-git-send-email-suzuki.poulose@arm.com> <20180704155104.GN4828@arm.com> Message-ID: <12d1832a-1a13-7dd4-662b-addf58400789@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/04/2018 04:51 PM, Will Deacon wrote: > Hi Suzuki, > > On Fri, Jun 29, 2018 at 12:15:35PM +0100, Suzuki K Poulose wrote: >> Allow specifying the physical address size for a new VM via >> the kvm_type argument for KVM_CREATE_VM ioctl. This allows >> us to finalise the stage2 page table format as early as possible >> and hence perform the right checks on the memory slots without >> complication. The size is encoded as Log2(PA_Size) in the bits[7:0] >> of the type field and can encode more information in the future if >> required. The IPA size is still capped at 40bits. >> >> Cc: Marc Zyngier >> Cc: Christoffer Dall >> Cc: Peter Maydel >> Cc: Paolo Bonzini >> Cc: Radim Kr?m?? >> Signed-off-by: Suzuki K Poulose >> --- >> arch/arm/include/asm/kvm_mmu.h | 2 ++ >> arch/arm64/include/asm/kvm_arm.h | 10 +++------- >> arch/arm64/include/asm/kvm_mmu.h | 2 ++ >> include/uapi/linux/kvm.h | 10 ++++++++++ >> virt/kvm/arm/arm.c | 24 ++++++++++++++++++++++-- >> 5 files changed, 39 insertions(+), 9 deletions(-) > > [...] > >> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h >> index 4df9bb6..fa4cab0 100644 >> --- a/include/uapi/linux/kvm.h >> +++ b/include/uapi/linux/kvm.h >> @@ -751,6 +751,16 @@ struct kvm_ppc_resize_hpt { >> #define KVM_S390_SIE_PAGE_OFFSET 1 >> >> /* >> + * On arm/arm64, machine type can be used to request the physical >> + * address size for the VM. Bits [7-0] have been reserved for the >> + * PA size shift (i.e, log2(PA_Size)). For backward compatibility, >> + * value 0 implies the default IPA size, which is 40bits. >> + */ >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK 0xff >> +#define KVM_VM_TYPE_ARM_PHYS_SHIFT(x) \ >> + ((x) & KVM_VM_TYPE_ARM_PHYS_SHIFT_MASK) > > This seems like you're allocating quite a lot of bits in a non-extensible > interface to a fairly esoteric parameter. Would it be better to add another > ioctl, or condense the number of sizes you support instead? As I explained in the other thread, we need the size as soon as the VM is created. The major challenge is keeping the backward compatibility by mapping 0 to 40bits. I will give it a thought. Suzuki