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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 249F8C4345F for ; Thu, 25 Apr 2024 21:55:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A9AA66B0083; Thu, 25 Apr 2024 17:55:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A4B3B6B0093; Thu, 25 Apr 2024 17:55:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 938F66B0098; Thu, 25 Apr 2024 17:55:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 76EF16B0083 for ; Thu, 25 Apr 2024 17:55:31 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 37D9BA13AD for ; Thu, 25 Apr 2024 21:55:31 +0000 (UTC) X-FDA: 82049411262.03.6702101 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) by imf12.hostedemail.com (Postfix) with ESMTP id 808664000F for ; Thu, 25 Apr 2024 21:55:28 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=1U5SXr2g; spf=pass (imf12.hostedemail.com: domain of 3T9EqZgYKCNQI40D926EE6B4.2ECB8DKN-CCAL02A.EH6@flex--seanjc.bounces.google.com designates 209.85.216.74 as permitted sender) smtp.mailfrom=3T9EqZgYKCNQI40D926EE6B4.2ECB8DKN-CCAL02A.EH6@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1714082128; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=RsYl5l4pMgJWCav/WMt8FHwRjQ9Kn5L/ws+uvKXVHfw=; b=DMLVbDVemJZJ8AVWn5wkXV87ANIdYdzRoiZXUn3OnFS9I8BLgnpo0g/XLtHCcvg7HUBcpP vtTXT1ftdznXshX+f35sMcIN9i6AbcRJpBJl88bGS428JdJdgNkdPqxSZ5CeTTJDRspnZ4 MzWB+W89fXaSMaYTGL5dIQnv/Fylh/8= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=1U5SXr2g; spf=pass (imf12.hostedemail.com: domain of 3T9EqZgYKCNQI40D926EE6B4.2ECB8DKN-CCAL02A.EH6@flex--seanjc.bounces.google.com designates 209.85.216.74 as permitted sender) smtp.mailfrom=3T9EqZgYKCNQI40D926EE6B4.2ECB8DKN-CCAL02A.EH6@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1714082128; a=rsa-sha256; cv=none; b=569raZE4E5fVQu9KKbNfRM3CnS4g2/uwTFiIMe2agx6v4ppiTTM8AToUh+OTb8kSY2rDRR F8cK5A+bTkDaB9a3UsSEm+lt8LNi5pp+WspThYRUnarlXaPT462tMixiXpPn/ccicVvYRK 1Ze8VBxUpNxZh1irUPJcahu6P5AJTBY= Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2a517457163so1589989a91.3 for ; Thu, 25 Apr 2024 14:55:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1714082127; x=1714686927; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=RsYl5l4pMgJWCav/WMt8FHwRjQ9Kn5L/ws+uvKXVHfw=; b=1U5SXr2g3syXVuqGi5NzI+Y/EeStetb9zXtczzGjOysHCl9M9JJMKsYLDVltqxyF9g 7Px7QEnk2ymMb+rdVq8CzYxm3Ni5uTRLz/NQlvZQ0ld8F4wXANhLvSkYvyReyNcnygZY srx9XmHLIXfMIb2x/LkzGXQMXnXtnhdKtEYouFgdgf3aTk27ecN0QByoyY+Rflv+ue1y JWoQ9z1QcV+HdD8wgJFEa/L2+pvBJU8NgZ6s6puhXhmPfA2qDSuw3+xXyUAQ62LK8Pj8 m8aiMuvYN3+2BLlZxCYZ2VYUVCHXkYl4liwHqWhch3buC3ZoBQUNkWTcSgCAYqYV+wnc gDeg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714082127; x=1714686927; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=RsYl5l4pMgJWCav/WMt8FHwRjQ9Kn5L/ws+uvKXVHfw=; b=mPuDDjGSskGxLKTlHWV+dGHN7v9rSAE5u0CQ2MVzYkihphidELVWvlMxnXs+UMD3Mz EsmjVMKDwOXeoSPEYkR8cpM4D46M1sq8w3FymAtDnjSBm6/oTWCZlOKZtgygP/SDLj2I YOsjthFjlmXC0ER6eidphQDPZ7Tb39iIG3fiVRnz0FsRnHEXcbW0nAgb8o227mzgZDpD 0KrWgQ8TTq5H7EAXSghHWRHnB44Hdf49/I1Cy4XGwxPQ/Kq3YWI6HeFy5PGgpN3hMFO6 +6uuhpjagJeIsnB9GRuXL7KG2/Uv31mWZYQDjXOnZfgrHJfwrxvFPOqn55gATkA84O4b mBcQ== X-Forwarded-Encrypted: i=1; AJvYcCWJpaC5TJUwKmxo1C5Laz8nloYHuvhd67i6Oa09/IWPFiq3xhEFplY6Zb6EfFMyS4QfzNMSMMFz95pLpZYg4iuxvOA= X-Gm-Message-State: AOJu0YwYMBQoLB5v0cEHihD3+M9pIU+ua79ZxkQ5Ifvuo5+HPtekaUVP gQzRVS3NMU8qRVMSMGnbVyun9GJKlET/GgmBAegAy07wgJIKn+6wBgMMftZZIk/CTxvEubfbBR5 4IQ== X-Google-Smtp-Source: AGHT+IHJjopOQrAy3bDBQrp6IQy93j3DR0aHwuFk/XSs4EC7EEAp9HrJQM06y5gG8vjnVdS4Ht9jUntHwjU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:d396:b0:2af:3c8f:12bc with SMTP id q22-20020a17090ad39600b002af3c8f12bcmr46744pju.8.1714082127170; Thu, 25 Apr 2024 14:55:27 -0700 (PDT) Date: Thu, 25 Apr 2024 14:55:25 -0700 In-Reply-To: <20240425205245.aga3cyo5qa5xfnee@amd.com> Mime-Version: 1.0 References: <20240421180122.1650812-1-michael.roth@amd.com> <20240421180122.1650812-4-michael.roth@amd.com> <20240425205245.aga3cyo5qa5xfnee@amd.com> Message-ID: Subject: Re: [PATCH v14 03/22] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests From: Sean Christopherson To: Michael Roth Cc: kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, jroedel@suse.de, thomas.lendacky@amd.com, hpa@zytor.com, ardb@kernel.org, pbonzini@redhat.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.com, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, dovmurik@linux.ibm.com, tobin@ibm.com, bp@alien8.de, vbabka@suse.cz, kirill@shutemov.name, ak@linux.intel.com, tony.luck@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, pankaj.gupta@amd.com, liam.merwick@oracle.com, Brijesh Singh Content-Type: text/plain; charset="us-ascii" X-Stat-Signature: chnshnayi75kuy3h1a975yhyb9o4fobz X-Rspamd-Queue-Id: 808664000F X-Rspamd-Server: rspam10 X-Rspam-User: X-HE-Tag: 1714082128-158676 X-HE-Meta: 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 9FBKVDgU 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000027, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Apr 25, 2024, Michael Roth wrote: > On Wed, Apr 24, 2024 at 01:21:49PM -0700, Sean Christopherson wrote: > > On Sun, Apr 21, 2024, Michael Roth wrote: > > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > > > index 6e31cb408dd8..1d2264e93afe 100644 > > > --- a/arch/x86/kvm/svm/sev.c > > > +++ b/arch/x86/kvm/svm/sev.c > > > @@ -33,9 +33,11 @@ > > > #include "cpuid.h" > > > #include "trace.h" > > > > > > -#define GHCB_VERSION_MAX 1ULL > > > +#define GHCB_VERSION_MAX 2ULL > > > #define GHCB_VERSION_MIN 1ULL > > > > This needs a userspace control. Being unable to limit the GHCB version advertised > > to the guest is going to break live migration of SEV-ES VMs, e.g. if a pool of > > hosts has some kernels running this flavor of KVM, and some hosts running an > > older KVM that doesn't support v2. > > > > The requirements for implementing the non-SNP aspects of the GHCB > version 2 protocol are fairly minimal, and KVM_SEV_INIT2 is already > migration incompatible with older kernels running KVM_SEV_ES_INIT (e.g. > migrate to newer host, shutdown, start -> measurement failure). There > are QEMU patches here that allow for controlling this via QEMU versioned > machine types to handle this [1] > > So I think it makes sense to go ahead move to GHCB version 2 as the base > version for all SEV-ES/SNP guests created via KVM_SEV_INIT2, and leave > KVM_SEV_ES_INIT restricted to GHCB version 1. Hmm, I like that. Dangle a carrot to get folks to switch to KVM_SEV_INIT2. > This could be done in a pretty self-contained way for SEV-ES by applying > the following patches from this series which are the version 2 protocol > interfaces also applicable to SEV-ES: > > KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests > KVM: SEV: Add support to handle AP reset MSR protocol > KVM: SEV: Add support for GHCB-based termination requests > > And then applying the below patch on top to set GHCB version 1 or 2 > accordingly for SEV-ES. (and relocating the GHCB_VERSION_MAX bump to the > below patch as well, although it's not really used at that point so > could also just be dropped completely). > > Then in the future we can extend KVM_SEV_INIT2 to allow specifying > specific/newer versions of the GHCB protocol when that becomes needed. Any reason not to let userspace restrict the GHCB protocol from the get-go? It seems inevitable that KVM will need to support that at some point, we'd have a wee bit more confidence that we didn't botch the definition of KVM_SEV_INIT2 and end up with KVM_SEV_INIT3, and in the unlikely event some poor provider gets into a situation where guests are crashing because they don't handle v2 correctly, userspace can workaround the issue without need to extend KVM's uAPI. > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 28140bc8af27..229cb630b540 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -87,6 +87,7 @@ struct kvm_sev_info { > struct list_head regions_list; /* List of registered regions */ > u64 ap_jump_table; /* SEV-ES AP Jump Table address */ > u64 vmsa_features; > + u64 ghcb_version; /* Highest guest GHCB protocol version allowed */ This can/should be a u16, no? > struct kvm *enc_context_owner; /* Owner of copied encryption context */ > struct list_head mirror_vms; /* List of VMs mirroring */ > struct list_head mirror_entry; /* Use as a list entry of mirrors */