From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 744136B0387 for ; Tue, 7 Mar 2017 06:57:53 -0500 (EST) Received: by mail-wm0-f71.google.com with SMTP id v190so714021wme.0 for ; Tue, 07 Mar 2017 03:57:53 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id j137si220598wmj.0.2017.03.07.03.57.51 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 07 Mar 2017 03:57:52 -0800 (PST) Date: Tue, 7 Mar 2017 12:57:30 +0100 From: Borislav Petkov Subject: Re: [RFC PATCH v2 07/32] x86/efi: Access EFI data as encrypted when SEV is active Message-ID: <20170307115730.rmsmluv42m5xnylf@pd.tnic> References: <148846752022.2349.13667498174822419498.stgit@brijesh-build-machine> <148846760142.2349.8522516472305792434.stgit@brijesh-build-machine> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <148846760142.2349.8522516472305792434.stgit@brijesh-build-machine> Sender: owner-linux-mm@kvack.org List-ID: To: Brijesh Singh , Matt Fleming Cc: simon.guinot@sequanux.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, linux-pci@vger.kernel.org, linus.walleij@linaro.org, gary.hook@amd.com, linux-mm@kvack.org, paul.gortmaker@windriver.com, hpa@zytor.com, cl@linux.com, dan.j.williams@intel.com, aarcange@redhat.com, sfr@canb.auug.org.au, andriy.shevchenko@linux.intel.com, herbert@gondor.apana.org.au, bhe@redhat.com, xemul@parallels.com, joro@8bytes.org, x86@kernel.org, peterz@infradead.org, piotr.luc@intel.com, mingo@redhat.com, msalter@redhat.com, ross.zwisler@linux.intel.com, dyoung@redhat.com, thomas.lendacky@amd.com, jroedel@suse.de, keescook@chromium.org, arnd@arndb.de, toshi.kani@hpe.com, mathieu.desnoyers@efficios.com, luto@kernel.org, devel@linuxdriverproject.org, bhelgaas@google.com, tglx@linutronix.de, mchehab@kernel.org, iamjoonsoo.kim@lge.com, labbott@fedoraproject.org, tony.luck@intel.com, alexandre.bounine@idt.com, kuleshovmail@gmail.com, linux-kernel@vger.kernel.org, mcgrof@kernel.org, mst@redhat.com, linux-crypto@vger.kernel.org, tj@kernel.org, pbonzini@redhat.com, akpm@linux-foundation.org, davem@davemloft.net On Thu, Mar 02, 2017 at 10:13:21AM -0500, Brijesh Singh wrote: > From: Tom Lendacky > > EFI data is encrypted when the kernel is run under SEV. Update the > page table references to be sure the EFI memory areas are accessed > encrypted. > > Signed-off-by: Tom Lendacky > Signed-off-by: Brijesh Singh This SOB chain looks good. > --- > arch/x86/platform/efi/efi_64.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c > index 2d8674d..9a76ed8 100644 > --- a/arch/x86/platform/efi/efi_64.c > +++ b/arch/x86/platform/efi/efi_64.c > @@ -45,6 +45,7 @@ > #include > #include > #include > +#include > > /* > * We allocate runtime services regions bottom-up, starting from -4G, i.e. > @@ -286,7 +287,10 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) > * as trim_bios_range() will reserve the first page and isolate it away > * from memory allocators anyway. > */ > - if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, _PAGE_RW)) { > + pf = _PAGE_RW; > + if (sev_active()) > + pf |= _PAGE_ENC; > + if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) { > pr_err("Failed to create 1:1 mapping for the first page!\n"); > return 1; > } > @@ -329,6 +333,9 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va) > if (!(md->attribute & EFI_MEMORY_WB)) > flags |= _PAGE_PCD; > > + if (sev_active()) > + flags |= _PAGE_ENC; > + So I'm wondering if we could avoid this sprinkling of _PAGE_ENC in the EFI code by defining something like __supported_pte_mask but called __efi_base_page_flags or so which has _PAGE_ENC cleared in the SME case, i.e., when baremetal and has it set in the SEV case. Then we could simply OR in __efi_base_page_flags which the SME/SEV code will set appropriately early enough. Hmm. Matt, what do you think? -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix ImendA?rffer, Jane Smithard, Graham Norton, HRB 21284 (AG NA 1/4 rnberg) -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org