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 56351C4332F for ; Wed, 8 Nov 2023 08:22:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235275AbjKHIWH (ORCPT ); Wed, 8 Nov 2023 03:22:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230004AbjKHIWF (ORCPT ); Wed, 8 Nov 2023 03:22:05 -0500 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 29945D79; Wed, 8 Nov 2023 00:22:03 -0800 (PST) Received: from [IPV6:2a02:a420:71:5cf3:d970:1912:3461:64ee] (77-63-77-130.mobile.kpn.net [77.63.77.130]) by linux.microsoft.com (Postfix) with ESMTPSA id 9410320B74C0; Wed, 8 Nov 2023 00:21:53 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9410320B74C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1699431722; bh=03JP0tJ3Bi+fFo0pgjJYRDq8To5NVAbwjQsCIdj9JDs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hdt7PdHkf+50r6gE6NWW+/pIDX2zfbYOV7NoETPr3DYDNgijoTrcFeMSI6o0Edrwb vFvYSXQkGL49i3UBCl5+CVuzHGSvTyTJLWc5pIqXwmSvlcd/WdIBtLOcb4TH4GpobD BOs9muG+PEzuUmU9OORX5W0IrTPvUBPzQ3d+Ax6Y= Message-ID: <503e778f-6324-44ca-b057-afe510ceea0f@linux.microsoft.com> Date: Wed, 8 Nov 2023 09:21:51 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 06/50] x86/sev: Add the host SEV-SNP initialization support Content-Language: en-US To: Tom Lendacky , Borislav Petkov , 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, 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, pgonda@google.com, peterz@infradead.org, srinivas.pandruvada@linux.intel.com, rientjes@google.com, dovmurik@linux.ibm.com, tobin@ibm.com, 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, jarkko@kernel.org, ashish.kalra@amd.com, nikunj.dadhania@amd.com, pankaj.gupta@amd.com, liam.merwick@oracle.com, zhi.a.wang@intel.com, Brijesh Singh References: <20231016132819.1002933-1-michael.roth@amd.com> <20231016132819.1002933-7-michael.roth@amd.com> <20231107163142.GAZUpmbt/i3himIf+E@fat_crate.local> <8ec38db1-5ccf-4684-bc0d-d48579ebf0d0@amd.com> From: Jeremi Piotrowski In-Reply-To: <8ec38db1-5ccf-4684-bc0d-d48579ebf0d0@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/11/2023 19:32, Tom Lendacky wrote: > On 11/7/23 10:31, Borislav Petkov wrote: >> >> And the stuff that needs to happen once, needs to be called once too. >> >>> + >>> +    return snp_get_rmptable_info(&rmp_base, &rmp_size); >>> +} >>> + >>>   static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) >>>   { >>>       u64 msr; >>> @@ -659,6 +674,9 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) >>>           if (!(msr & MSR_K7_HWCR_SMMLOCK)) >>>               goto clear_sev; >>>   +        if (cpu_has(c, X86_FEATURE_SEV_SNP) && !early_rmptable_check()) >>> +            goto clear_snp; >>> + >>>           return; >>>     clear_all: >>> @@ -666,6 +684,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) >>>   clear_sev: >>>           setup_clear_cpu_cap(X86_FEATURE_SEV); >>>           setup_clear_cpu_cap(X86_FEATURE_SEV_ES); >>> +clear_snp: >>>           setup_clear_cpu_cap(X86_FEATURE_SEV_SNP); >>>       } >>>   } >> >> ... >> >>> +bool snp_get_rmptable_info(u64 *start, u64 *len) >>> +{ >>> +    u64 max_rmp_pfn, calc_rmp_sz, rmp_sz, rmp_base, rmp_end; >>> + >>> +    rdmsrl(MSR_AMD64_RMP_BASE, rmp_base); >>> +    rdmsrl(MSR_AMD64_RMP_END, rmp_end); >>> + >>> +    if (!(rmp_base & RMP_ADDR_MASK) || !(rmp_end & RMP_ADDR_MASK)) { >>> +        pr_err("Memory for the RMP table has not been reserved by BIOS\n"); >>> +        return false; >>> +    } >> >> If you're masking off bits 0-12 above... > > Because the RMP_END MSR, most specifically, has a default value of 0x1fff, where bits [12:0] are reserved. So to specifically check if the MSR has been set to a non-zero end value, the bit are masked off. However, ... > Do you have a source for this? Because the APM vol. 2, table A.7 says the reset value of RMP_END is all zeros. Thanks, Jeremi