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 6D7DAC001DE for ; Tue, 15 Aug 2023 16:02:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238411AbjHOQBc (ORCPT ); Tue, 15 Aug 2023 12:01:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233892AbjHOQA7 (ORCPT ); Tue, 15 Aug 2023 12:00:59 -0400 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BCB0127 for ; Tue, 15 Aug 2023 09:00:58 -0700 (PDT) Received: by mail-ed1-x52b.google.com with SMTP id 4fb4d7f45d1cf-5257d67368bso4827a12.0 for ; Tue, 15 Aug 2023 09:00:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1692115257; x=1692720057; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=XpJb+OJfG+8YyFrgPemLQHLQMcBP2sLxedbL+4WkyQI=; b=12OED/nj8x27vkzaTPH4huvtjj1jVfmU0hALhPhRV6AHmDCTdQhEw61qFu0CiIfn5o xv23dzfwiXjilKF2V4mskgtYOlyAItz4mGPTN2wpAueITgQOP78cOJbBTI5T+qpxeb1D i+enASWV3RDnzBDsM9sJhV1dKddbywFKKUa61O57PtAiIAuwyGiXXM14LOto23UpYAxE PGemjOd/8RRrs6Lx5h5wH0joSWfAVxRthE6BXEwns8z2BhGRUhYJtOemEbyDvBnO44s/ oV7zywqJBfWLvArDGYmw2b/xFekU2Hy5QZ25lKkvn+5v2YLe42/YEkzYEm+UrksNlC2f uQYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692115257; x=1692720057; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XpJb+OJfG+8YyFrgPemLQHLQMcBP2sLxedbL+4WkyQI=; b=R9GtHQnihrCkiRQxUVkP7zqs3XD55xW71xdqIhzCb3OW1HIr4P2QAx+aSpsoErvMnO HJG+gQ/bDjotW73TpBIqiCFzNZ1kcRdXluQqbQGcW9gHIfZXn/rj2uZnq/z7RYwtvsep fFYz8OhC687VGwvcoFPnaiHFDvZcLUnSAJq+o9Ff3cB4vXXaJL19Spam8gGzZpR+9fGL VMRTO1K862WY5QbpehFBV+JOSknyrUbevZSzMiN/eEJU4xUIqlVLfRHXfEdlzm1bfe3W HpowjcMh8fRsMLy7NSmBkxMop0jqG5paeLUVwxHvJuDVp+CEPCQuE2dRly+CbT4Am+1Y Muaw== X-Gm-Message-State: AOJu0YxOEbthlxYVjRctFi4npQyVZWzklh6WpDqBWkmM9y+Fqfuq+SM5 Vk4CyJTYQrHQFAJWwCVs00Ufl1Mubq4MhDbOZPP/GQ== X-Google-Smtp-Source: AGHT+IEdGhK9M3JtHIkjAkwh3xNQNLfzowgWF508z3Uj0qlA890h/RB4apOdF96xxD3sICYqpWEaeKcnTbjgLEFFWtk= X-Received: by 2002:a50:9fa4:0:b0:506:b280:4993 with SMTP id c33-20020a509fa4000000b00506b2804993mr363704edf.2.1692115256934; Tue, 15 Aug 2023 09:00:56 -0700 (PDT) MIME-Version: 1.0 References: <20230612042559.375660-1-michael.roth@amd.com> <20230612042559.375660-43-michael.roth@amd.com> In-Reply-To: <20230612042559.375660-43-michael.roth@amd.com> From: Peter Gonda Date: Tue, 15 Aug 2023 10:00:45 -0600 Message-ID: Subject: Re: [PATCH RFC v9 42/51] KVM: SVM: Support SEV-SNP AP Creation NAE event 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, seanjc@google.com, vkuznets@redhat.com, jmattson@google.com, luto@kernel.org, dave.hansen@linux.intel.com, slp@redhat.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, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, liam.merwick@oracle.com, zhi.a.wang@intel.com, Brijesh Singh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org > + > + switch (request) { > + case SVM_VMGEXIT_AP_CREATE_ON_INIT: > + kick = false; > + fallthrough; > + case SVM_VMGEXIT_AP_CREATE: > + if (!page_address_valid(vcpu, svm->vmcb->control.exit_info_2)) { > + vcpu_unimpl(vcpu, "vmgexit: invalid AP VMSA address [%#llx] from guest\n", > + svm->vmcb->control.exit_info_2); > + ret = -EINVAL; > + goto out; > + } > + > + /* > + * Malicious guest can RMPADJUST a large page into VMSA which > + * will hit the SNP erratum where the CPU will incorrectly signal > + * an RMP violation #PF if a hugepage collides with the RMP entry > + * of VMSA page, reject the AP CREATE request if VMSA address from > + * guest is 2M aligned. > + */ > + if (IS_ALIGNED(svm->vmcb->control.exit_info_2, PMD_SIZE)) { > + vcpu_unimpl(vcpu, > + "vmgexit: AP VMSA address [%llx] from guest is unsafe as it is 2M aligned\n", > + svm->vmcb->control.exit_info_2); In this case and maybe the above case can we instead return an error to the guest instead of a #GP? I think Tom suggested: SW_EXITINFO1[31:0] to 2 (meaning there was an error with the VMGEXIT request) and SW_EXITINFO2 to 5 (The NAE event input was not valid (e.g., an invalid SW_EXITINFO1 value for the AP Jump Table NAE event). This way a non-malicious but buggy or naive guest gets a little more information and a chance to retry the request? > + ret = -EINVAL; > + goto out; > + } > + > + target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2; > + break; > + case SVM_VMGEXIT_AP_DESTROY: > + break; > + default: > + vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n", > + request); > + ret = -EINVAL; > + break; > + } > +