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 E730EC43334 for ; Thu, 2 Jun 2022 11:59:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234656AbiFBL7j (ORCPT ); Thu, 2 Jun 2022 07:59:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234655AbiFBL7d (ORCPT ); Thu, 2 Jun 2022 07:59:33 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B96713C1C9; Thu, 2 Jun 2022 04:59:24 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id C5A77616ED; Thu, 2 Jun 2022 11:59:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC475C385A5; Thu, 2 Jun 2022 11:59:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654171163; bh=7wB+JR5L26iDvtyWDCetlIK56JTTRdnWPOpw4hq0hUQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mKIyrmFq1Njrtb0hkqfMBDD7/axk70SVWIc24ndvLN5aOOHN75sVLOBegWJC2SESb qFX0I/Gdw7tvBLWoqsESOzEc5e9VZUwY/xy1zIBRJy7k/+IEVXwoZjf+h2OpS7JMT6 Y1Al7wRSciVyot0vRc4H97bfIX8T1OVJqWo/zJg3h7ryDCH+Nl9e8RfT587T86EjHY H5W+spyZqm4jcp00H306fFAEPzS2OtSLdHWqgSve3NAWIr4/sY52Vt0dmIh49UFfPG V0hlPs87m+HgmekoaHiVIehSiDdFXyyHOJJlEblkIhhBMWyEzUwTmgqWlrJeQF3lEr OBcEnyFOChQbA== Date: Thu, 2 Jun 2022 14:57:31 +0300 From: Jarkko Sakkinen To: Brijesh Singh Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Borislav Petkov , Michael Roth , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH Part2 v5 04/45] x86/sev: Add RMP entry lookup helpers Message-ID: References: <20210820155918.7518-1-brijesh.singh@amd.com> <20210820155918.7518-5-brijesh.singh@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210820155918.7518-5-brijesh.singh@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 20, 2021 at 10:58:37AM -0500, Brijesh Singh wrote: > The snp_lookup_page_in_rmptable() can be used by the host to read the RMP > entry for a given page. The RMP entry format is documented in AMD PPR, see > https://bugzilla.kernel.org/attachment.cgi?id=296015. > > Signed-off-by: Brijesh Singh > --- > arch/x86/include/asm/sev.h | 27 ++++++++++++++++++++++++ > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > include/linux/sev.h | 30 ++++++++++++++++++++++++++ > 3 files changed, 100 insertions(+) > create mode 100644 include/linux/sev.h > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index a5f0a1c3ccbe..5b1a6a075c47 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -9,6 +9,7 @@ > #define __ASM_ENCRYPTED_STATE_H > > #include > +#include > #include > #include > #include > @@ -77,6 +78,32 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); > > /* RMP page size */ > #define RMP_PG_SIZE_4K 0 > +#define RMP_TO_X86_PG_LEVEL(level) (((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M) > + > +/* > + * The RMP entry format is not architectural. The format is defined in PPR > + * Family 19h Model 01h, Rev B1 processor. > + */ > +struct __packed rmpentry { > + union { > + struct { > + u64 assigned : 1, > + pagesize : 1, > + immutable : 1, > + rsvd1 : 9, > + gpa : 39, > + asid : 10, > + vmsa : 1, > + validated : 1, > + rsvd2 : 1; > + } info; > + u64 low; > + }; > + u64 high; > +}; > + > +#define rmpentry_assigned(x) ((x)->info.assigned) > +#define rmpentry_pagesize(x) ((x)->info.pagesize) > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 7936c8139c74..f383d2a89263 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -54,6 +54,8 @@ > * bookkeeping, the range need to be added during the RMP entry lookup. > */ > #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 > +#define RMPENTRY_SHIFT 8 > +#define rmptable_page_offset(x) (RMPTABLE_CPU_BOOKKEEPING_SZ + (((unsigned long)x) >> RMPENTRY_SHIFT)) > > /* For early boot hypervisor communication in SEV-ES enabled guests */ > static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); > @@ -2376,3 +2378,44 @@ static int __init snp_rmptable_init(void) > * available after subsys_initcall(). > */ > fs_initcall(snp_rmptable_init); > + > +static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + unsigned long vaddr, paddr = pfn << PAGE_SHIFT; > + struct rmpentry *entry, *large_entry; > + > + if (!pfn_valid(pfn)) > + return ERR_PTR(-EINVAL); > + > + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > + return ERR_PTR(-ENXIO); > + > + vaddr = rmptable_start + rmptable_page_offset(paddr); > + if (unlikely(vaddr > rmptable_end)) > + return ERR_PTR(-ENXIO); > + > + entry = (struct rmpentry *)vaddr; > + > + /* Read a large RMP entry to get the correct page level used in RMP entry. */ > + vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK); > + large_entry = (struct rmpentry *)vaddr; > + *level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry)); > + > + return entry; > +} > + > +/* > + * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, > + * and -errno if there is no corresponding RMP entry. According to /usr/include/asm-generic/errno.h, there is 133 error codes. Why you need so many just to say that there is no entry? > + */ > +int snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + struct rmpentry *e; > + > + e = __snp_lookup_rmpentry(pfn, level); > + if (IS_ERR(e)) > + return PTR_ERR(e); > + > + return !!rmpentry_assigned(e); > +} > +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); > diff --git a/include/linux/sev.h b/include/linux/sev.h > new file mode 100644 > index 000000000000..1a68842789e1 > --- /dev/null > +++ b/include/linux/sev.h > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * AMD Secure Encrypted Virtualization > + * > + * Author: Brijesh Singh nit: this is redundant. Each git commit has an author-field. > + */ > + > +#ifndef __LINUX_SEV_H > +#define __LINUX_SEV_H > + > +/* RMUPDATE detected 4K page and 2MB page overlap. */ > +#define RMPUPDATE_FAIL_OVERLAP 7 > + > +#ifdef CONFIG_AMD_MEM_ENCRYPT > +int snp_lookup_rmpentry(u64 pfn, int *level); > +int psmash(u64 pfn); > +int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); > +int rmp_make_shared(u64 pfn, enum pg_level level); > +#else > +static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } > +static inline int psmash(u64 pfn) { return -ENXIO; } > +static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, > + bool immutable) > +{ > + return -ENODEV; > +} > +static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } > + > +#endif /* CONFIG_AMD_MEM_ENCRYPT */ > +#endif /* __LINUX_SEV_H */ > -- > 2.17.1 > BR, Jarkko