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=-8.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 CB861C2BA1A for ; Mon, 6 Apr 2020 22:27:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 88336206C3 for ; Mon, 6 Apr 2020 22:27:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="LE5hfzFI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726713AbgDFW1f (ORCPT ); Mon, 6 Apr 2020 18:27:35 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:54934 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726312AbgDFW1f (ORCPT ); Mon, 6 Apr 2020 18:27:35 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 036MMt5x108035; Mon, 6 Apr 2020 22:27:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=hatYsnMsoLP49Dkz3Xe01FIPGrFSbV6v6CCCS0dvdgA=; b=LE5hfzFI/xAFqKt8BOcF0wUJNQ2ND3hG5A++Z92PuYbYgcNGzAVqcL9qnEXTChQpLd4Q 3j96YJgJ2o4Hhx20O5rQhVZ37h4uv/k6c6VqAjWT6NZGWFBT/lsIJUefXPqWdEF9vk9n CuArbaQiKVyDngT/xfOhY6KfRJlXc0DahWnwa8NTnnvmKlrTsjwAqnHHgVJaeSMdOvF8 tKXFMuvH9hj9OVYMOTORwepvhEIHcC88pA7SGIv3Ofwqy2HGXQmqyBrsfil6lSWnQ1aa ZmGJ847Q/Qxn4cbI0QCscF5xIXGB4WOZ+iybDXQcBEqeBvpIpi3RsK7AIt3YUgv7jhvm KA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 306jvn1hyc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 06 Apr 2020 22:27:13 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 036MMQvT186515; Mon, 6 Apr 2020 22:27:12 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3020.oracle.com with ESMTP id 30839rb43e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 06 Apr 2020 22:27:12 +0000 Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 036MRAd9006224; Mon, 6 Apr 2020 22:27:10 GMT Received: from localhost.localdomain (/10.159.148.184) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 06 Apr 2020 15:27:10 -0700 Subject: Re: [PATCH v6 08/14] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall To: Ashish Kalra Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, joro@8bytes.org, bp@suse.de, thomas.lendacky@amd.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, rientjes@google.com, srutherford@google.com, luto@kernel.org, brijesh.singh@amd.com References: <265ef8a0ab75f01bc673cce6ddcf7988c7623943.1585548051.git.ashish.kalra@amd.com> <8d1baef8-c5ea-e8ac-0a9c-097aa20ea7aa@oracle.com> <20200403015748.GA26677@ashkalra_ubuntu_server> <20200403025846.GA27066@ashkalra_ubuntu_server> From: Krish Sadhukhan Message-ID: <2d710143-0e28-5534-7858-81eb296d3445@oracle.com> Date: Mon, 6 Apr 2020 15:27:08 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20200403025846.GA27066@ashkalra_ubuntu_server> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9583 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 spamscore=0 malwarescore=0 mlxscore=0 mlxlogscore=999 bulkscore=0 suspectscore=2 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004060169 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9583 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 suspectscore=2 mlxlogscore=999 mlxscore=0 bulkscore=0 adultscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 malwarescore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004060169 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/2/20 7:58 PM, Ashish Kalra wrote: > On Fri, Apr 03, 2020 at 01:57:48AM +0000, Ashish Kalra wrote: >> On Thu, Apr 02, 2020 at 06:31:54PM -0700, Krish Sadhukhan wrote: >>> On 3/29/20 11:22 PM, Ashish Kalra wrote: >>>> From: Brijesh Singh >>>> >>>> This hypercall is used by the SEV guest to notify a change in the page >>>> encryption status to the hypervisor. The hypercall should be invoked >>>> only when the encryption attribute is changed from encrypted -> decrypted >>>> and vice versa. By default all guest pages are considered encrypted. >>>> >>>> Cc: Thomas Gleixner >>>> Cc: Ingo Molnar >>>> Cc: "H. Peter Anvin" >>>> Cc: Paolo Bonzini >>>> Cc: "Radim Krčmář" >>>> Cc: Joerg Roedel >>>> Cc: Borislav Petkov >>>> Cc: Tom Lendacky >>>> Cc: x86@kernel.org >>>> Cc: kvm@vger.kernel.org >>>> Cc: linux-kernel@vger.kernel.org >>>> Signed-off-by: Brijesh Singh >>>> Signed-off-by: Ashish Kalra >>>> --- >>>> Documentation/virt/kvm/hypercalls.rst | 15 +++++ >>>> arch/x86/include/asm/kvm_host.h | 2 + >>>> arch/x86/kvm/svm.c | 95 +++++++++++++++++++++++++++ >>>> arch/x86/kvm/vmx/vmx.c | 1 + >>>> arch/x86/kvm/x86.c | 6 ++ >>>> include/uapi/linux/kvm_para.h | 1 + >>>> 6 files changed, 120 insertions(+) >>>> >>>> diff --git a/Documentation/virt/kvm/hypercalls.rst b/Documentation/virt/kvm/hypercalls.rst >>>> index dbaf207e560d..ff5287e68e81 100644 >>>> --- a/Documentation/virt/kvm/hypercalls.rst >>>> +++ b/Documentation/virt/kvm/hypercalls.rst >>>> @@ -169,3 +169,18 @@ a0: destination APIC ID >>>> :Usage example: When sending a call-function IPI-many to vCPUs, yield if >>>> any of the IPI target vCPUs was preempted. >>>> + >>>> + >>>> +8. KVM_HC_PAGE_ENC_STATUS >>>> +------------------------- >>>> +:Architecture: x86 >>>> +:Status: active >>>> +:Purpose: Notify the encryption status changes in guest page table (SEV guest) >>>> + >>>> +a0: the guest physical address of the start page >>>> +a1: the number of pages >>>> +a2: encryption attribute >>>> + >>>> + Where: >>>> + * 1: Encryption attribute is set >>>> + * 0: Encryption attribute is cleared >>>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >>>> index 98959e8cd448..90718fa3db47 100644 >>>> --- a/arch/x86/include/asm/kvm_host.h >>>> +++ b/arch/x86/include/asm/kvm_host.h >>>> @@ -1267,6 +1267,8 @@ struct kvm_x86_ops { >>>> bool (*apic_init_signal_blocked)(struct kvm_vcpu *vcpu); >>>> int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu); >>>> + int (*page_enc_status_hc)(struct kvm *kvm, unsigned long gpa, >>>> + unsigned long sz, unsigned long mode); >>>> }; >>>> struct kvm_arch_async_pf { >>>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >>>> index 7c2721e18b06..1d8beaf1bceb 100644 >>>> --- a/arch/x86/kvm/svm.c >>>> +++ b/arch/x86/kvm/svm.c >>>> @@ -136,6 +136,8 @@ struct kvm_sev_info { >>>> int fd; /* SEV device fd */ >>>> unsigned long pages_locked; /* Number of pages locked */ >>>> struct list_head regions_list; /* List of registered regions */ >>>> + unsigned long *page_enc_bmap; >>>> + unsigned long page_enc_bmap_size; >>>> }; >>>> struct kvm_svm { >>>> @@ -1991,6 +1993,9 @@ static void sev_vm_destroy(struct kvm *kvm) >>>> sev_unbind_asid(kvm, sev->handle); >>>> sev_asid_free(sev->asid); >>>> + >>>> + kvfree(sev->page_enc_bmap); >>>> + sev->page_enc_bmap = NULL; >>>> } >>>> static void avic_vm_destroy(struct kvm *kvm) >>>> @@ -7593,6 +7598,94 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) >>>> return ret; >>>> } >>>> +static int sev_resize_page_enc_bitmap(struct kvm *kvm, unsigned long new_size) >>>> +{ >>>> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >>>> + unsigned long *map; >>>> + unsigned long sz; >>>> + >>>> + if (sev->page_enc_bmap_size >= new_size) >>>> + return 0; >>>> + >>>> + sz = ALIGN(new_size, BITS_PER_LONG) / 8; >>>> + >>>> + map = vmalloc(sz); >>> >>> Just wondering why we can't directly modify sev->page_enc_bmap. >>> >> Because the page_enc_bitmap needs to be re-sized here, it needs to be >> expanded here. OK. > I don't believe there is anything is like a realloc() kind of equivalent > for the kmalloc() interfaces. > > Thanks, > Ashish > >>>> + if (!map) { >>>> + pr_err_once("Failed to allocate encrypted bitmap size %lx\n", >>>> + sz); >>>> + return -ENOMEM; >>>> + } >>>> + >>>> + /* mark the page encrypted (by default) */ >>>> + memset(map, 0xff, sz); >>>> + >>>> + bitmap_copy(map, sev->page_enc_bmap, sev->page_enc_bmap_size); >>>> + kvfree(sev->page_enc_bmap); >>>> + >>>> + sev->page_enc_bmap = map; >>>> + sev->page_enc_bmap_size = new_size; >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa, >>>> + unsigned long npages, unsigned long enc) >>>> +{ >>>> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; >>>> + kvm_pfn_t pfn_start, pfn_end; >>>> + gfn_t gfn_start, gfn_end; >>>> + int ret; >>>> + >>>> + if (!sev_guest(kvm)) >>>> + return -EINVAL; >>>> + >>>> + if (!npages) >>>> + return 0; >>>> + >>>> + gfn_start = gpa_to_gfn(gpa); >>>> + gfn_end = gfn_start + npages; >>>> + >>>> + /* out of bound access error check */ >>>> + if (gfn_end <= gfn_start) >>>> + return -EINVAL; >>>> + >>>> + /* lets make sure that gpa exist in our memslot */ >>>> + pfn_start = gfn_to_pfn(kvm, gfn_start); >>>> + pfn_end = gfn_to_pfn(kvm, gfn_end); >>>> + >>>> + if (is_error_noslot_pfn(pfn_start) && !is_noslot_pfn(pfn_start)) { >>>> + /* >>>> + * Allow guest MMIO range(s) to be added >>>> + * to the page encryption bitmap. >>>> + */ >>>> + return -EINVAL; >>>> + } >>>> + >>>> + if (is_error_noslot_pfn(pfn_end) && !is_noslot_pfn(pfn_end)) { >>>> + /* >>>> + * Allow guest MMIO range(s) to be added >>>> + * to the page encryption bitmap. >>>> + */ >>>> + return -EINVAL; >>>> + } >>> >>> It seems is_error_noslot_pfn() covers both cases - i) gfn slot is absent, >>> ii) failure to translate to pfn. So do we still need is_noslot_pfn() ? >>> >> We do need to check for !is_noslot_pfn(..) additionally as the MMIO ranges will not >> be having a slot allocated. The comments above is_error_noslot_pfn() seem to indicate that it covers both cases, "not in slot" and "failure to translate"... Reviewed-by: Krish Sadhukhan >> >> Thanks, >> Ashish >> >>>> + >>>> + mutex_lock(&kvm->lock); >>>> + ret = sev_resize_page_enc_bitmap(kvm, gfn_end); >>>> + if (ret) >>>> + goto unlock; >>>> + >>>> + if (enc) >>>> + __bitmap_set(sev->page_enc_bmap, gfn_start, >>>> + gfn_end - gfn_start); >>>> + else >>>> + __bitmap_clear(sev->page_enc_bmap, gfn_start, >>>> + gfn_end - gfn_start); >>>> + >>>> +unlock: >>>> + mutex_unlock(&kvm->lock); >>>> + return ret; >>>> +} >>>> + >>>> static int svm_mem_enc_op(struct kvm *kvm, void __user *argp) >>>> { >>>> struct kvm_sev_cmd sev_cmd; >>>> @@ -7995,6 +8088,8 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = { >>>> .need_emulation_on_page_fault = svm_need_emulation_on_page_fault, >>>> .apic_init_signal_blocked = svm_apic_init_signal_blocked, >>>> + >>>> + .page_enc_status_hc = svm_page_enc_status_hc, >>> >>> Why not place it where other encryption ops are located ? >>> >>>         ... >>> >>>         .mem_enc_unreg_region >>> >>> +      .page_enc_status_hc = svm_page_enc_status_hc >>> >>>> }; >>>> static int __init svm_init(void) >>>> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c >>>> index 079d9fbf278e..f68e76ee7f9c 100644 >>>> --- a/arch/x86/kvm/vmx/vmx.c >>>> +++ b/arch/x86/kvm/vmx/vmx.c >>>> @@ -8001,6 +8001,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { >>>> .nested_get_evmcs_version = NULL, >>>> .need_emulation_on_page_fault = vmx_need_emulation_on_page_fault, >>>> .apic_init_signal_blocked = vmx_apic_init_signal_blocked, >>>> + .page_enc_status_hc = NULL, >>>> }; >>>> static void vmx_cleanup_l1d_flush(void) >>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>>> index cf95c36cb4f4..68428eef2dde 100644 >>>> --- a/arch/x86/kvm/x86.c >>>> +++ b/arch/x86/kvm/x86.c >>>> @@ -7564,6 +7564,12 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) >>>> kvm_sched_yield(vcpu->kvm, a0); >>>> ret = 0; >>>> break; >>>> + case KVM_HC_PAGE_ENC_STATUS: >>>> + ret = -KVM_ENOSYS; >>>> + if (kvm_x86_ops->page_enc_status_hc) >>>> + ret = kvm_x86_ops->page_enc_status_hc(vcpu->kvm, >>>> + a0, a1, a2); >>>> + break; >>>> default: >>>> ret = -KVM_ENOSYS; >>>> break; >>>> diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h >>>> index 8b86609849b9..847b83b75dc8 100644 >>>> --- a/include/uapi/linux/kvm_para.h >>>> +++ b/include/uapi/linux/kvm_para.h >>>> @@ -29,6 +29,7 @@ >>>> #define KVM_HC_CLOCK_PAIRING 9 >>>> #define KVM_HC_SEND_IPI 10 >>>> #define KVM_HC_SCHED_YIELD 11 >>>> +#define KVM_HC_PAGE_ENC_STATUS 12 >>>> /* >>>> * hypercalls use architecture specific