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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53B78C43217 for ; Thu, 7 Oct 2021 14:39:01 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id C1BE261175 for ; Thu, 7 Oct 2021 14:39:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C1BE261175 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 37E1B4B313; Thu, 7 Oct 2021 10:39:00 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@redhat.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6cUvqZFxJ8NC; Thu, 7 Oct 2021 10:38:58 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D2CB64B2EA; Thu, 7 Oct 2021 10:38:58 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C386B4B2E7 for ; Thu, 7 Oct 2021 10:38:57 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8tSVlBMBsiqP for ; Thu, 7 Oct 2021 10:38:56 -0400 (EDT) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B0E1C4B273 for ; Thu, 7 Oct 2021 10:38:56 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633617536; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=NGm1yWS8geF2sO0H/4Ce/J+RgIXVQpoAvhPhIp+yNF0=; b=iY/EjFClUtHIbvmZ42U6+VdHEwF/PvLHqAepZ6uQnuVcBejROEMDJLAf6dHZi/L86tE5OZ cnNwN1gBkLPAgRVGG0CBnuaxsBEEpuxJ/qbKwujNBvVc7qVxTBFFEAsC4MepIWDcKU0iP2 69dwGYMBH49pRLGprdLxoYeDYRfRaAw= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-564-nIRErnAyMD-j0Yrxq7S69Q-1; Thu, 07 Oct 2021 10:38:55 -0400 X-MC-Unique: nIRErnAyMD-j0Yrxq7S69Q-1 Received: by mail-wr1-f72.google.com with SMTP id h11-20020adfa4cb000000b00160c791a550so4693027wrb.6 for ; Thu, 07 Oct 2021 07:38:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=NGm1yWS8geF2sO0H/4Ce/J+RgIXVQpoAvhPhIp+yNF0=; b=DsY7cX1s9AQ9gPnyi05NDgHknAT/+Fd2Wr5C7enNo9sUiX6aPHLFaoA70Yi7qck+/A 5bjmFaGW6OetNlxyIYviMDyk11VGvX+wOMxprWzBfL/tbExFld1INPAysyW4sudBuLF+ ZYlkAf2HFuWMIczNBFx9AyFcK6XJ3Z698wdiE6PthQqDSDvNDn0c/JwkugSkKWKvAKAv xxeoyV0OHsofMx8zLG67XOPSmSN7b9R3+tUkaVHLERpocve1Rtemliar+RLpy+xnRMwj mHC4aVDaZUHiriWUYCR7mqsE5lPLZvlo69k81+Fh8Y7bS1Svm/GXKcAyXaeFxPcJVQbA nhnw== X-Gm-Message-State: AOAM5324U22V7jA1JJxgPy5hD23DeXoWotpJ3sUVXZY4CooO5Tj2MFi1 M96PUhHrCRQPHYLTmWEs90maeggleRua0VyzI3xz1HYYzS/BCjGnhsQYpH0yFC8JeErJ0kGlR+P VpfImnOcao4MZc5NxuJwrs7xe X-Received: by 2002:adf:bb09:: with SMTP id r9mr6004161wrg.238.1633617534503; Thu, 07 Oct 2021 07:38:54 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxO9BCo0zdcmxbDxAudW4jdTSomLkbbEHDoD+axd3gGY/vYr4NNhmBMpyQQvOrtL3YclzCczw== X-Received: by 2002:adf:bb09:: with SMTP id r9mr6004113wrg.238.1633617534208; Thu, 07 Oct 2021 07:38:54 -0700 (PDT) Received: from gator (nat-pool-brq-u.redhat.com. [213.175.37.12]) by smtp.gmail.com with ESMTPSA id a2sm9231329wrv.15.2021.10.07.07.38.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Oct 2021 07:38:53 -0700 (PDT) Date: Thu, 7 Oct 2021 16:38:52 +0200 From: Andrew Jones To: Marc Zyngier Subject: Re: [PATCH v2 10/16] KVM: arm64: Add some documentation for the MMIO guard feature Message-ID: <20211007143852.pyae42sbovi4vk23@gator> References: <20211004174849.2831548-1-maz@kernel.org> <20211004174849.2831548-11-maz@kernel.org> MIME-Version: 1.0 In-Reply-To: <20211004174849.2831548-11-maz@kernel.org> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=drjones@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Cc: kernel-team@android.com, kvm@vger.kernel.org, Srivatsa Vaddagiri , linux-kernel@vger.kernel.org, Steven Price , Shanker R Donthineni , will@kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Mon, Oct 04, 2021 at 06:48:43PM +0100, Marc Zyngier wrote: > Document the hypercalls user for the MMIO guard infrastructure. > > Signed-off-by: Marc Zyngier > --- > Documentation/virt/kvm/arm/index.rst | 1 + > Documentation/virt/kvm/arm/mmio-guard.rst | 74 +++++++++++++++++++++++ > 2 files changed, 75 insertions(+) > create mode 100644 Documentation/virt/kvm/arm/mmio-guard.rst > > diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst > index 78a9b670aafe..e77a0ee2e2d4 100644 > --- a/Documentation/virt/kvm/arm/index.rst > +++ b/Documentation/virt/kvm/arm/index.rst > @@ -11,3 +11,4 @@ ARM > psci > pvtime > ptp_kvm > + mmio-guard > diff --git a/Documentation/virt/kvm/arm/mmio-guard.rst b/Documentation/virt/kvm/arm/mmio-guard.rst > new file mode 100644 > index 000000000000..8b3c852c5d92 > --- /dev/null > +++ b/Documentation/virt/kvm/arm/mmio-guard.rst > @@ -0,0 +1,74 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +============== > +KVM MMIO guard > +============== > + > +KVM implements device emulation by handling translation faults to any > +IPA range that is not contained in a memory slot. Such a translation > +fault is in most cases passed on to userspace (or in rare cases to the > +host kernel) with the address, size and possibly data of the access > +for emulation. > + > +Should the guest exit with an address that is not one that corresponds > +to an emulatable device, userspace may take measures that are not the > +most graceful as far as the guest is concerned (such as terminating it > +or delivering a fatal exception). > + > +There is also an element of trust: by forwarding the request to > +userspace, the kernel assumes that the guest trusts userspace to do > +the right thing. > + > +The KVM MMIO guard offers a way to mitigate this last point: a guest > +can request that only certain regions of the IPA space are valid as > +MMIO. Only these regions will be handled as an MMIO, and any other > +will result in an exception being delivered to the guest. > + > +This relies on a set of hypercalls defined in the KVM-specific range, > +using the HVC64 calling convention. > + > +* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_INFO > + > + ============== ======== ================================ > + Function ID: (uint32) 0xC6000002 > + Arguments: none > + Return Values: (int64) NOT_SUPPORTED(-1) on error, or > + (uint64) Protection Granule (PG) size in > + bytes (r0) > + ============== ======== ================================ > + > +* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_ENROLL > + > + ============== ======== ============================== > + Function ID: (uint32) 0xC6000003 > + Arguments: none > + Return Values: (int64) NOT_SUPPORTED(-1) on error, or > + RET_SUCCESS(0) (r0) > + ============== ======== ============================== > + > +* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_MAP > + > + ============== ======== ==================================== > + Function ID: (uint32) 0xC6000004 > + Arguments: (uint64) The base of the PG-sized IPA range > + that is allowed to be accessed as > + MMIO. Must be aligned to the PG size > + (r1) > + (uint64) Index in the MAIR_EL1 register > + providing the memory attribute that > + is used by the guest (r2) ^^ some tabs got in here > + Return Values: (int64) NOT_SUPPORTED(-1) on error, or > + RET_SUCCESS(0) (r0) > + ============== ======== ==================================== > + > +* ARM_SMCCC_KVM_FUNC_MMIO_GUARD_UNMAP > + > + ============== ======== ====================================== > + Function ID: (uint32) 0xC6000005 > + Arguments: (uint64) PG-sized IPA range aligned to the PG > + size which has been previously mapped. > + Must be aligned to the PG size and > + have been previously mapped (r1) > + Return Values: (int64) NOT_SUPPORTED(-1) on error, or > + RET_SUCCESS(0) (r0) > + ============== ======== ====================================== > -- > 2.30.2 > Otherwise, Reviewed-by: Andrew Jones Thanks, drew _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm