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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31915C38159 for ; Fri, 20 Jan 2023 23:17:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229699AbjATXR2 (ORCPT ); Fri, 20 Jan 2023 18:17:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229494AbjATXR1 (ORCPT ); Fri, 20 Jan 2023 18:17:27 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D153472B8; Fri, 20 Jan 2023 15:17:25 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 591FCB82AA6; Fri, 20 Jan 2023 23:17:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7510DC433D2; Fri, 20 Jan 2023 23:17:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674256643; bh=SoqwK6Lbe/mngQK8/Z0v1FXpq/aJOBcKcs9SVP31/ss=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HAucgctXzN9/951JWEJjbzvwMgSm5mu/FK37EvGSRiIsqcGwiwm0Sd2MMd+k58d9G Fp0qyJPu11GHZFkhDwIPCnhjqIlM0o13n/mq14ncbX/1ZNxhnX5nQdbv2s9DDIINdU zkynKCEzKf2AjpTOkByQy3zeIem0IvE7iniX+PDZ2Zcga80SXcyT6Cx9V/XJYFmqMW 8xlCk1YB8+/16Wtm8akBQmfuMqE/uj4FKd8v2julqdoNeZv+InV1oBUkWNUHg/n+Y7 w3Xu/Cx89Yyy8Ab+QikkvjG1ytxt2d3Pki9e+jRBI/Cop2LOoXGWd8r6aIjK57H9Ce WGCs8eUeLB8uQ== Date: Fri, 20 Jan 2023 23:17:20 +0000 From: Jarkko Sakkinen To: "Kalra, Ashish" Cc: Michael Roth , 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, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.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, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, alpergun@google.com, dgilbert@redhat.com, harald@profian.com, Brijesh Singh , Pavan Kumar Paluri Subject: Re: [PATCH RFC v7 37/64] KVM: SVM: Add KVM_SNP_INIT command Message-ID: References: <20221214194056.161492-1-michael.roth@amd.com> <20221214194056.161492-38-michael.roth@amd.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="Mwn5vxNlX4YIa3fN" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Mwn5vxNlX4YIa3fN Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Jan 05, 2023 at 05:37:20PM -0600, Kalra, Ashish wrote: > Hello Jarkko, > > On 12/31/2022 8:27 AM, Jarkko Sakkinen wrote: > > On Wed, Dec 14, 2022 at 01:40:29PM -0600, Michael Roth wrote: > > > static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) > > > { > > > struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info; > > > @@ -260,13 +279,23 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp) > > > return ret; > > > sev->active = true; > > > - sev->es_active = argp->id == KVM_SEV_ES_INIT; > > > + sev->es_active = (argp->id == KVM_SEV_ES_INIT || argp->id == KVM_SEV_SNP_INIT); > > > + sev->snp_active = argp->id == KVM_SEV_SNP_INIT; > > > asid = sev_asid_new(sev); > > > if (asid < 0) > > > goto e_no_asid; > > > sev->asid = asid; > > > - ret = sev_platform_init(&argp->error); > > > + if (sev->snp_active) { > > > + ret = verify_snp_init_flags(kvm, argp); > > > + if (ret) > > > + goto e_free; > > > + > > > + ret = sev_snp_init(&argp->error, false); > > > + } else { > > > + ret = sev_platform_init(&argp->error); > > > + } > > > > Couldn't sev_snp_init() and sev_platform_init() be called unconditionally > > in order? > > > > Since there is a hardware constraint that SNP init needs to always happen > > before platform init, shouldn't SNP init happen as part of > > __sev_platform_init_locked() instead? > > > > On Genoa there is currently an issue that if we do an SNP_INIT before an > SEV_INIT and then attempt to launch a SEV guest that may fail, so we need to > keep SNP INIT and SEV INIT separate. > > We need to provide a way to run (existing) SEV guests on a system that > supports SNP without doing an SNP_INIT at all. > > This is done using psp_init_on_probe parameter of the CCP module to avoid > doing either SNP/SEV firmware initialization during module load and then > defer the firmware initialization till someone launches a guest of one > flavor or the other. > > And then sev_guest_init() does either SNP or SEV firmware init depending on > the type of the guest being launched. OK, got it, thank you. I have not noticed the init_on_probe for sev_snp_init() before. Was it in earlier patch set version? The benefit of having everything in __sev_platform_init_lock() would be first less risk of shooting yourself into foot, and also no need to pass init_on_probe to sev_snp_init() as it would be internal to sev-dev.c, and no need for special cases for callers. It is in my opinion internals of the SEV driver to guarantee the order. E.g. changes to svm/sev.c would be then quite trivial. > > I found these call sites for __sev_platform_init_locked(), none of which > > follow the correct call order: > > > > * sev_guest_init() > > As explained above, this call site is important for deferring the firmware > initialization to an actual guest launch. > > > * sev_ioctl_do_pek_csr > > * sev_ioctl_do_pdh_export() > > * sev_ioctl_do_pek_import() > > * sev_ioctl_do_pek_pdh_gen() What happens if any of these are called before sev_guest_init()? They only call __sev_platform_init_locked(). > > * sev_pci_init() > > > > For me it looks like a bit flakky API use to have sev_snp_init() as an API > > call. > > > > I would suggest to make SNP init internal to the ccp driver and take care > > of the correct orchestration over there. > > > > Due to Genoa issue, we may still need SNP init and SEV init to be invoked > separately outside the CCP driver. > > > Also, how it currently works in this patch set, if the firmware did not > > load correctly, SNP init halts the whole system. The version check needs > > to be in all call paths. > > > > Yes, i agree with that. Attached the fix I sent in private earlier. > Thanks, > Ashish BR, Jarkko --Mwn5vxNlX4YIa3fN Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0001-crypto-ccp-Prevent-a-spurious-SEV_CMD_SNP_INIT-trigg.patch" >From f24054af9eeeb0314bbd0c37bd97ff38e2ded717 Mon Sep 17 00:00:00 2001 From: Jarkko Sakkinen Date: Sun, 4 Dec 2022 06:17:07 +0000 Subject: [PATCH] crypto: ccp: Prevent a spurious SEV_CMD_SNP_INIT triggered by sev_guest_init() Move the firmware version check from sev_pci_init() to sev_snp_init(). Signed-off-by: Jarkko Sakkinen --- drivers/crypto/ccp/sev-dev.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 7c5698bde655..08787d998f15 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1387,6 +1387,12 @@ static int __sev_snp_init_locked(int *error) if (sev->snp_initialized) return 0; + if (!sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR)) { + dev_dbg(sev->dev, "SEV-SNP support requires firmware version >= %d:%d\n", + SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR); + return 0; + } + /* * The SNP_INIT requires the MSR_VM_HSAVE_PA must be set to 0h * across all cores. @@ -2319,25 +2325,19 @@ void sev_pci_init(void) } } + rc = sev_snp_init(&error, true); + if (rc) + /* + * Don't abort the probe if SNP INIT failed, + * continue to initialize the legacy SEV firmware. + */ + dev_err(sev->dev, "SEV-SNP: failed to INIT error %#x\n", error); + /* * If boot CPU supports SNP, then first attempt to initialize * the SNP firmware. */ if (cpu_feature_enabled(X86_FEATURE_SEV_SNP)) { - if (!sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR)) { - dev_err(sev->dev, "SEV-SNP support requires firmware version >= %d:%d\n", - SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR); - } else { - rc = sev_snp_init(&error, true); - if (rc) { - /* - * Don't abort the probe if SNP INIT failed, - * continue to initialize the legacy SEV firmware. - */ - dev_err(sev->dev, "SEV-SNP: failed to INIT error %#x\n", error); - } - } - /* * Allocate the intermediate buffers used for the legacy command handling. */ -- 2.38.1 --Mwn5vxNlX4YIa3fN--