From patchwork Tue Feb 14 19:42:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Garnier X-Patchwork-Id: 9572629 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BA50160573 for ; Tue, 14 Feb 2017 19:44:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B6D2A28391 for ; Tue, 14 Feb 2017 19:44:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAB59283E1; Tue, 14 Feb 2017 19:44:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 41BCE28391 for ; Tue, 14 Feb 2017 19:44:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753245AbdBNTnY (ORCPT ); Tue, 14 Feb 2017 14:43:24 -0500 Received: from mail-oi0-f50.google.com ([209.85.218.50]:34101 "EHLO mail-oi0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751873AbdBNTnK (ORCPT ); Tue, 14 Feb 2017 14:43:10 -0500 Received: by mail-oi0-f50.google.com with SMTP id s203so76405757oie.1 for ; Tue, 14 Feb 2017 11:43:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=iitYwezpjUyKVmLZ7WNApIXSeCIdeGxFdEcLZjsh3tM=; b=FcN7wVg/2c8Ia2vGBx+J/t2x6g/UvK4bSKSXXz2fgQuWtIAGv7Uqfd3Jvhe55TlflG csZx2u2VNIqHK15IkTPKrQTX4p0CtZWJGD9WvyfS6Bn+mVSzNKWpqqw91VXhyqGcN2R8 mzrNlxrAtj/dWOgoGTr+QIdbobZhPNpuTPIb9ox2mSWahQ1uuz42Jpr9S/x3IS/T3oGC Kxwhvts3s8on2NycypenSOWlwdTd7wF8K57TKYR3duKj21I/b+jUIvRIqhMmzAq+jU++ Aqe2+smViYMpDr/uWwYujmpYcYMgRyJv54GaMnDjo1YkwHwgxt+/FSJzJNgvS8feQZk1 GP2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=iitYwezpjUyKVmLZ7WNApIXSeCIdeGxFdEcLZjsh3tM=; b=j1gcYgJBqFSUQVhsVtrrsam2PHDYzf8zghu54PRFASUG0e+GhKSjpntaAJUiRjFhY/ 7bfIWHd1K1dzYk1etKKhWn4JdJ/DZnjXSaxHtD8tpjZlAJNO+sU/dPqa3K+PXOJ85P5N GQ5cFEEg/0FrTT7yF2cVIUix/x4BH5xPZDcmisMD+MEXLoANV5AIlz6Sx/ID6EX0a5LO p6Y/OBt2/6aB5MYCenHUGC8pSuDj3G/J9Yk6GelfRlwrxSvkyocNCdFvfX24s/9tfs1O YPtoOl/zlLm8GBUz747lSn2+hfqrKruY5JT+TTtzyW7Pec59fpwqQdhiNi/x5blAtWdt UEpA== X-Gm-Message-State: AMke39lrbEpN+P5YNoGuP9On/wAfm2jm4ZDaBgNOaRpgrN/YaGj5KBTi9MgKtNw1U6ISV8wc X-Received: by 10.84.176.137 with SMTP id v9mr4000927plb.59.1487101389206; Tue, 14 Feb 2017 11:43:09 -0800 (PST) Received: from skynet.sea.corp.google.com ([100.100.206.185]) by smtp.gmail.com with ESMTPSA id r78sm2804161pfl.63.2017.02.14.11.43.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 14 Feb 2017 11:43:08 -0800 (PST) From: Thomas Garnier To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Thomas Garnier , Kees Cook , Andy Lutomirski , Borislav Petkov , Paul Gortmaker , Andy Lutomirski , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Jiri Kosina , Matt Fleming , Ard Biesheuvel , Boris Ostrovsky , Juergen Gross , Rusty Russell , Peter Zijlstra , Christian Borntraeger , "Luis R . Rodriguez" , He Chen , Brian Gerst , Stanislaw Gruszka , Arnd Bergmann , Adam Buchbinder , Dave Hansen , Vitaly Kuznetsov , Josh Poimboeuf , Tim Chen , Rik van Riel , Andi Kleen , Jiri Olsa , Michael Ellerman , Joerg Roedel , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-pm@vger.kernel.org, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org, lguest@lists.ozlabs.org, kvm@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: [PATCH v3 4/4] KVM: VMX: Simplify segment_base Date: Tue, 14 Feb 2017 11:42:59 -0800 Message-Id: <20170214194259.75960-4-thgarnie@google.com> X-Mailer: git-send-email 2.11.0.483.g087da7b7c-goog In-Reply-To: <20170214194259.75960-1-thgarnie@google.com> References: <20170214194259.75960-1-thgarnie@google.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The KVM segment_base function is confusing. This patch replaces integers with appropriate flags, simplify constructs and add comments. Signed-off-by: Thomas Garnier --- Based on next-20170213 --- arch/x86/kvm/vmx.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 99167f20bc34..edb8326108dd 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2062,25 +2062,35 @@ static unsigned long segment_base(u16 selector) struct desc_struct *d; unsigned long table_base; unsigned long v; + u32 high32; - if (!(selector & ~3)) + if (!(selector & ~SEGMENT_RPL_MASK)) return 0; - table_base = get_current_gdt_rw_vaddr(); - - if (selector & 4) { /* from ldt */ + /* LDT selector */ + if ((selector & SEGMENT_TI_MASK) == SEGMENT_LDT) { u16 ldt_selector = kvm_read_ldt(); - if (!(ldt_selector & ~3)) + if (!(ldt_selector & ~SEGMENT_RPL_MASK)) return 0; table_base = segment_base(ldt_selector); + } else { + table_base = get_current_gdt_rw_vaddr(); } - d = (struct desc_struct *)(table_base + (selector & ~7)); + + d = (struct desc_struct *)table_base + (selector >> 3); v = get_desc_base(d); #ifdef CONFIG_X86_64 - if (d->s == 0 && (d->type == 2 || d->type == 9 || d->type == 11)) - v |= ((unsigned long)((struct ldttss_desc64 *)d)->base3) << 32; + /* + * Extend the virtual address if we have a system descriptor entry for + * LDT or TSS (available or busy). + */ + if (d->s == 0 && (d->type == DESC_LDT || d->type == DESC_TSS || + d->type == 11/*Busy TSS */)) { + high32 = ((struct ldttss_desc64 *)d)->base3; + v |= (u64)high32 << 32; + } #endif return v; }