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 4E79FC32771 for ; Mon, 26 Sep 2022 11:59:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239026AbiIZL7U (ORCPT ); Mon, 26 Sep 2022 07:59:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239559AbiIZLzy (ORCPT ); Mon, 26 Sep 2022 07:55:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26B5079A44; Mon, 26 Sep 2022 03:51:10 -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 ams.source.kernel.org (Postfix) with ESMTPS id C2A4BB80954; Mon, 26 Sep 2022 10:37:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AEF5C433D6; Mon, 26 Sep 2022 10:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664188673; bh=o1ieDuvPKq+cO2ZvqSA7F+mCLGrZYaQlZxA++JjjbX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Umg8DpXjmwSASS57GGL6VHz3niw6pP7Fh6XA/38sF1eP/XvcNoG8qnkg6xRFrcLIw f4aZRKq22LMn3CVObrB4hzgGSkm6iYHHz7JXYBGcolK84DY2aime5daU2d0dVayoYb upnQelpqnx2tVouPkAo8swLt/L42k25P7Tb9vjp8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.15 052/148] KVM: x86: Inject #UD on emulated XSETBV if XSAVES isnt enabled Date: Mon, 26 Sep 2022 12:11:26 +0200 Message-Id: <20220926100757.978247637@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220926100756.074519146@linuxfoundation.org> References: <20220926100756.074519146@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson commit 50b2d49bafa16e6311ab2da82f5aafc5f9ada99b upstream. Inject #UD when emulating XSETBV if CR4.OSXSAVE is not set. This also covers the "XSAVE not supported" check, as setting CR4.OSXSAVE=1 #GPs if XSAVE is not supported (and userspace gets to keep the pieces if it forces incoherent vCPU state). Add a comment to kvm_emulate_xsetbv() to call out that the CPU checks CR4.OSXSAVE before checking for intercepts. AMD'S APM implies that #UD has priority (says that intercepts are checked before #GP exceptions), while Intel's SDM says nothing about interception priority. However, testing on hardware shows that both AMD and Intel CPUs prioritize the #UD over interception. Fixes: 02d4160fbd76 ("x86: KVM: add xsetbv to the emulator") Cc: stable@vger.kernel.org Cc: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Message-Id: <20220824033057.3576315-4-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 3 +++ arch/x86/kvm/x86.c | 1 + 2 files changed, 4 insertions(+) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4122,6 +4122,9 @@ static int em_xsetbv(struct x86_emulate_ { u32 eax, ecx, edx; + if (!(ctxt->ops->get_cr(ctxt, 4) & X86_CR4_OSXSAVE)) + return emulate_ud(ctxt); + eax = reg_read(ctxt, VCPU_REGS_RAX); edx = reg_read(ctxt, VCPU_REGS_RDX); ecx = reg_read(ctxt, VCPU_REGS_RCX); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1021,6 +1021,7 @@ static int __kvm_set_xcr(struct kvm_vcpu int kvm_emulate_xsetbv(struct kvm_vcpu *vcpu) { + /* Note, #UD due to CR4.OSXSAVE=0 has priority over the intercept. */ if (static_call(kvm_x86_get_cpl)(vcpu) != 0 || __kvm_set_xcr(vcpu, kvm_rcx_read(vcpu), kvm_read_edx_eax(vcpu))) { kvm_inject_gp(vcpu, 0);