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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 7D299C4338F for ; Thu, 12 Aug 2021 09:05:15 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id EA9B460E9B for ; Thu, 12 Aug 2021 09:05:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EA9B460E9B 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 64836407F4; Thu, 12 Aug 2021 05:05:14 -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 sXoRA8eJGKWu; Thu, 12 Aug 2021 05:05:10 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 4F05E49E93; Thu, 12 Aug 2021 05:05:10 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C201440839 for ; Thu, 12 Aug 2021 05:05:09 -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 lgYHuK4eEPqg for ; Thu, 12 Aug 2021 05:05:05 -0400 (EDT) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E143D407F4 for ; Thu, 12 Aug 2021 05:05:05 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628759105; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JgMWN7/eNl2nw6MdbRkVkIrc4drjFaFJaW8jw61Jzlk=; b=VkaZMFBnHG8t6faXW+wSIxKBhQ/7wpXJD1VHOSFwXelNS0d4Biu1k4qXvicixLa5bPRAja yT6CjXsZ98uzhLnjKVHOvNvt3hMSoMPvq1DyvB2X2K7UKwmO+sx/snv+DUftlgH3Kqu45n tMoyhQp8lMlc5lRhaPrE4cp32SHArBY= 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-225-koudisYJO0KbO_rNORYYAQ-1; Thu, 12 Aug 2021 05:05:02 -0400 X-MC-Unique: koudisYJO0KbO_rNORYYAQ-1 Received: by mail-wr1-f72.google.com with SMTP id x18-20020a5d49120000b0290154e9dcf3dbso1602665wrq.7 for ; Thu, 12 Aug 2021 02:05:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=JgMWN7/eNl2nw6MdbRkVkIrc4drjFaFJaW8jw61Jzlk=; b=gpSx2UIvOgqW5st4o0LYzXrQwQc5UavKq2aQvx0Jb9MjQyABeO0z2TX/6ISdH0ZtdK F4iIv9ge125KdIkbE+vSvnh1Km+QX15NF5fxjyr3FOx6AYnnQA1lpGSc81QWYU3juLSD RdC0tH90reK+Fu4hOBANfndSzhxfEZZx2Ms7ETFKishvXqFXuoMvVRSdetkynl1AjjNI MyfYMsuza9MCzLQKUMBs2qiqrMpuxWqGGpQzkNUiQ24DzqzP/159Ly54W8go1fe//pV+ jEPigPLl3/hOUB2Rx45B3hElGmVGreswK8tl53XbAtvqKmeCfQlrVYl4PmRNRY3rHgk7 oJ7w== X-Gm-Message-State: AOAM530cS6ylLL0zzB4iDRiL8UVNQL77bpLLYhl1woa7rQqh+SlzBWGB gCmyAJWQtDqpgGwTb0zePWBLNmpH9FiNBCb+WgSVbUT67Pod8r8XMq+7/27YVt6GdLzbOiPV5GT +e4e6TcTcHpNjwPAMPmrg1hHS X-Received: by 2002:a5d:6d03:: with SMTP id e3mr2798702wrq.153.1628759100830; Thu, 12 Aug 2021 02:05:00 -0700 (PDT) X-Google-Smtp-Source: ABdhPJw14l6W1wkrgjVxsT5cj4nrtOlS6mn0en/HDpnzJRRlmx+RwnP3XwnlZp0HL14993xrDLfaIA== X-Received: by 2002:a5d:6d03:: with SMTP id e3mr2798682wrq.153.1628759100598; Thu, 12 Aug 2021 02:05:00 -0700 (PDT) Received: from [192.168.3.132] (p4ff23d8b.dip0.t-ipconnect.de. [79.242.61.139]) by smtp.gmail.com with ESMTPSA id i21sm2300276wrb.62.2021.08.12.02.04.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 12 Aug 2021 02:05:00 -0700 (PDT) Subject: Re: [PATCH v2 1/2] KVM: Refactor kvm_arch_vcpu_fault() to return a struct page pointer To: Hou Wenlong , kvm@vger.kernel.org References: <1c510b24fc1d7cbae8aa4b69c0799ebd32e65b82.1628739116.git.houwenlong93@linux.alibaba.com> From: David Hildenbrand Organization: Red Hat Message-ID: <98adbd3c-ec6f-5689-1686-2a8a7909951a@redhat.com> Date: Thu, 12 Aug 2021 11:04:58 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <1c510b24fc1d7cbae8aa4b69c0799ebd32e65b82.1628739116.git.houwenlong93@linux.alibaba.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Cc: x86@kernel.org, Wanpeng Li , Benjamin Herrenschmidt , linux-mips@vger.kernel.org, Paul Mackerras , "H. Peter Anvin" , Claudio Imbrenda , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-s390@vger.kernel.org, Janosch Frank , Marc Zyngier , Joerg Roedel , Huacai Chen , Christian Borntraeger , Aleksandar Markovic , Ingo Molnar , Catalin Marinas , Vasily Gorbik , Heiko Carstens , kvm-ppc@vger.kernel.org, Borislav Petkov , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Jim Mattson , Thomas Bogendoerfer , Sean Christopherson , Cornelia Huck , linux-kernel@vger.kernel.org, Michael Ellerman , Paolo Bonzini , Vitaly Kuznetsov , linuxppc-dev@lists.ozlabs.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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On 12.08.21 06:02, Hou Wenlong wrote: > From: Sean Christopherson > > Refactor kvm_arch_vcpu_fault() to return 'struct page *' instead of > 'vm_fault_t' to simplify architecture specific implementations that do > more than return SIGBUS. Currently this only applies to s390, but a > future patch will move x86's pio_data handling into x86 where it belongs. > > No functional changed intended. > > Cc: Hou Wenlong > Signed-off-by: Sean Christopherson > Signed-off-by: Hou Wenlong > --- > arch/arm64/kvm/arm.c | 4 ++-- > arch/mips/kvm/mips.c | 4 ++-- > arch/powerpc/kvm/powerpc.c | 4 ++-- > arch/s390/kvm/kvm-s390.c | 12 ++++-------- > arch/x86/kvm/x86.c | 4 ++-- > include/linux/kvm_host.h | 2 +- > virt/kvm/kvm_main.c | 5 ++++- > 7 files changed, 17 insertions(+), 18 deletions(-) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index e9a2b8f27792..83f4ffe3e4f2 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -161,9 +161,9 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > return ret; > } > > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > { > - return VM_FAULT_SIGBUS; > + return NULL; > } > > > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c > index af9dd029a4e1..ae79874e6fd2 100644 > --- a/arch/mips/kvm/mips.c > +++ b/arch/mips/kvm/mips.c > @@ -1053,9 +1053,9 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) > return -ENOIOCTLCMD; > } > > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > { > - return VM_FAULT_SIGBUS; > + return NULL; > } > > int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index be33b5321a76..b9c21f9ab784 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -2090,9 +2090,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > return r; > } > > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > { > - return VM_FAULT_SIGBUS; > + return NULL; > } > > static int kvm_vm_ioctl_get_pvinfo(struct kvm_ppc_pvinfo *pvinfo) > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index 02574d7b3612..e1b69833e228 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -4979,17 +4979,13 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > return r; > } > > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > { > #ifdef CONFIG_KVM_S390_UCONTROL > - if ((vmf->pgoff == KVM_S390_SIE_PAGE_OFFSET) > - && (kvm_is_ucontrol(vcpu->kvm))) { > - vmf->page = virt_to_page(vcpu->arch.sie_block); > - get_page(vmf->page); > - return 0; > - } > + if (vmf->pgoff == KVM_S390_SIE_PAGE_OFFSET && kvm_is_ucontrol(vcpu->kvm)) > + return virt_to_page(vcpu->arch.sie_block); > #endif > - return VM_FAULT_SIGBUS; > + return NULL; > } > > /* Section: memory related */ > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 3cedc7cc132a..1e3bbe5cd33a 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -5347,9 +5347,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > return r; > } > > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf) > { > - return VM_FAULT_SIGBUS; > + return NULL; > } > > static int kvm_vm_ioctl_set_tss_addr(struct kvm *kvm, unsigned long addr) > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 492d183dd7d0..a949de534722 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -995,7 +995,7 @@ long kvm_arch_dev_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg); > long kvm_arch_vcpu_ioctl(struct file *filp, > unsigned int ioctl, unsigned long arg); > -vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf); > +struct page *kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf); > > int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext); > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 30d322519253..f7d21418971b 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3448,7 +3448,10 @@ static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf) > &vcpu->dirty_ring, > vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET); > else > - return kvm_arch_vcpu_fault(vcpu, vmf); > + page = kvm_arch_vcpu_fault(vcpu, vmf); > + if (!page) > + return VM_FAULT_SIGBUS; > + > get_page(page); > vmf->page = page; > return 0; > Reviewed-by: David Hildenbrand But at the same time I wonder if we should just get rid of CONFIG_KVM_S390_UCONTROL and consequently kvm_arch_vcpu_fault(). In practice CONFIG_KVM_S390_UCONTROL, is never enabled in any reasonable kernel build and consequently it's never tested; further, exposing the sie_block to user space allows user space to generate random SIE validity intercepts. CONFIG_KVM_S390_UCONTROL feels like something that should just be maintained out of tree by someone who really needs to hack deep into hw virtualization for testing purposes etc. -- Thanks, David / dhildenb _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm