From patchwork Fri Nov 22 22:39:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11258543 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0FD37138C for ; Fri, 22 Nov 2019 22:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA7C120721 for ; Fri, 22 Nov 2019 22:40:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727112AbfKVWkZ (ORCPT ); Fri, 22 Nov 2019 17:40:25 -0500 Received: from mga01.intel.com ([192.55.52.88]:61229 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726942AbfKVWkF (ORCPT ); Fri, 22 Nov 2019 17:40:05 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Nov 2019 14:40:04 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,231,1571727600"; d="scan'208";a="409029696" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by fmsmga006.fm.intel.com with ESMTP; 22 Nov 2019 14:40:04 -0800 From: Sean Christopherson To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 10/13] KVM: x86: Shrink the usercopy region of the emulation context Date: Fri, 22 Nov 2019 14:39:56 -0800 Message-Id: <20191122223959.13545-11-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191122223959.13545-1-sean.j.christopherson@intel.com> References: <20191122223959.13545-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Shuffle a few operand structs to the end of struct x86_emulate_ctxt and update the cache creation to whitelist only the region of the emulation context that is expected to be copied to/from user memory, e.g. the instruction operands, registers, and fetch/io/mem caches. Signed-off-by: Sean Christopherson --- arch/x86/kvm/kvm_emulate.h | 8 +++++--- arch/x86/kvm/x86.c | 12 ++++++------ 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 844e833609db..c25133080666 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -318,9 +318,6 @@ struct x86_emulate_ctxt { u8 intercept; u8 op_bytes; u8 ad_bytes; - struct operand src; - struct operand src2; - struct operand dst; int (*execute)(struct x86_emulate_ctxt *ctxt); int (*check_perm)(struct x86_emulate_ctxt *ctxt); /* @@ -345,6 +342,11 @@ struct x86_emulate_ctxt { u8 seg_override; u64 d; unsigned long _eip; + + /* Here begins the usercopy section. */ + struct operand src; + struct operand src2; + struct operand dst; struct operand memop; /* Fields above regs are cleared together. */ unsigned long _regs[NR_VCPU_REGS]; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 548cf3b659f5..418717876ad0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -231,13 +231,13 @@ static struct kmem_cache *x86_emulator_cache; static struct kmem_cache *kvm_alloc_emulator_cache(void) { - return kmem_cache_create_usercopy("x86_emulator", - sizeof(struct x86_emulate_ctxt), + unsigned int useroffset = offsetof(struct x86_emulate_ctxt, src); + unsigned int size = sizeof(struct x86_emulate_ctxt); + + return kmem_cache_create_usercopy("x86_emulator", size, __alignof__(struct x86_emulate_ctxt), - SLAB_ACCOUNT, - 0, - sizeof(struct x86_emulate_ctxt), - NULL); + SLAB_ACCOUNT, useroffset, + size - useroffset, NULL); } static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt);