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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3C68C4363A for ; Mon, 26 Oct 2020 19:40:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99D3620872 for ; Mon, 26 Oct 2020 19:40:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="T8hSiYDv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1793447AbgJZTkR (ORCPT ); Mon, 26 Oct 2020 15:40:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:38485 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1786270AbgJZTkR (ORCPT ); Mon, 26 Oct 2020 15:40:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603741215; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lpnjO+j0owMSyjQB1uE/7UdTp3Y8ra4ZJKBoSrw2Up0=; b=T8hSiYDvx8MzMr0l0E1/OetNdjJd7ynz7juwtOzUwY/Bv5XFxyfCxhY4WRVA20cNpqIkv9 Xq2bxyHWXkA1dX8l26dP1nzzQGam04yY/zu8LKXu7k6BbMls6Bbp5aMJbUnwvHSitZOOPD 27zu0HfzNHYxIhJim99QOaGOHsN8sHM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-578-xu2zlgm-O2K-fuMDMhbPEA-1; Mon, 26 Oct 2020 15:40:13 -0400 X-MC-Unique: xu2zlgm-O2K-fuMDMhbPEA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9BB9C804B66; Mon, 26 Oct 2020 19:40:11 +0000 (UTC) Received: from ovpn-113-173.rdu2.redhat.com (ovpn-113-173.rdu2.redhat.com [10.10.113.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 939966EF40; Mon, 26 Oct 2020 19:40:09 +0000 (UTC) Message-ID: <849d7acb00b3dadc3fc7db1e574c03dc74a06270.camel@redhat.com> Subject: Re: [PATCH v6 2/4] KVM: x86: report negative values from wrmsr emulation to userspace From: Qian Cai To: Maxim Levitsky , kvm@vger.kernel.org Cc: "H. Peter Anvin" , Ingo Molnar , Borislav Petkov , Vitaly Kuznetsov , Sean Christopherson , Joerg Roedel , Paolo Bonzini , Wanpeng Li , Thomas Gleixner , linux-kernel@vger.kernel.org, Jim Mattson , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Linus Torvalds Date: Mon, 26 Oct 2020 15:40:09 -0400 In-Reply-To: <20200922211025.175547-3-mlevitsk@redhat.com> References: <20200922211025.175547-1-mlevitsk@redhat.com> <20200922211025.175547-3-mlevitsk@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2020-09-23 at 00:10 +0300, Maxim Levitsky wrote: > This will allow the KVM to report such errors (e.g -ENOMEM) > to the userspace. > > Signed-off-by: Maxim Levitsky Reverting this and its dependency: 72f211ecaa80 KVM: x86: allow kvm_x86_ops.set_efer to return an error value on the top of linux-next (they have also unfortunately merged into the mainline at the same time) fixed an issue that a simple Intel KVM guest is unable to boot below. .config: http://people.redhat.com/qcai/x86.config qemu-kvm-4.2.0-34.module+el8.3.0+7976+077be4ec.x86_64 # /usr/libexec/qemu-kvm -name ubuntu-20.04-server-cloudimg -cpu host -smp 2 -m 2g -hda ./ubuntu-20.04-server-cloudimg.qcow2 -cdrom ./ubuntu-20.04-server-cloudimg.iso -nic user,hostfwd=tcp::2222-:22 -nographic [ 1.141022] evm: Initialising EVM extended attributes: [ 1.143344] evm: security.selinux [ 1.144968] evm: security.SMACK64 [ 1.146574] evm: security.SMACK64EXEC [ 1.148305] evm: security.SMACK64TRANSMUTE [ 1.150215] evm: security.SMACK64MMAP [ 1.151960] evm: security.apparmor [ 1.153755] evm: security.ima [ 1.155454] evm: security.capability [ 1.155456] evm: HMAC attrs: 0x1 [ 1.162331] ata1.00: ATA-7: QEMU HARDDISK, 2.5+, max UDMA/100 [ 1.162635] PM: Magic number: 8:937:635 [ 1.165607] ata1.00: 2147483648 sectors, multi 16: LBA48 [ 1.169799] scsi 0:0:0:0: Direct-Access ATA QEMU HARDDISK 2.5+ PQ: 0 ANSI: 5 [ 1.174196] rtc_cmos 00:00: setting system clock to 2020-10-26T13:38:53 UTC (1603719533) [ 1.178237] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 1.178293] sd 0:0:0:0: [sda] 2147483648 512-byte logical blocks: (1.10 TB/1.00 TiB) [ 1.180567] ata2.00: ATAPI: QEMU DVD-ROM, 2.5+, max UDMA/100 [ 1.183986] sd 0:0:0:0: [sda] Write Protect is off [error: kvm run failed No such file or directory RAX=0000000000000000 RBX=0000000000000000 RCX=0000000000000150 RDX=000000008000001c RSI=0000000000000000 RDI=0000000000000150 RBP=ffffb67840083e40 RSP=ffffb67840083e00 R8 =ffff931dfda17608 R9 =0000000000000000 R10=ffff931dfda17848 R11=0000000000000000 R12=0000000000000000 R13=00000000000000b7 R14=ffff931dfd4013c0 R15=ffffffffaa8f48d0 RIP=ffffffffaa078894 RFL=00000246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =0000 0000000000000000 ffffffff 00c00000 CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA] SS =0000 0000000000000000 ffffffff 00c00000 DS =0000 0000000000000000 ffffffff 00c00000 FS =0000 0000000000000000 ffffffff 00c00000 GS =0000 ffff931dfda00000 ffffffff 00c00000 LDT=0000 0000000000000000 ffffffff 00c00000 TR =0040 fffffe0000003000 0000206f 00008b00 DPL=0 TSS64-busy GDT= fffffe0000001000 0000007f IDT= fffffe0000000000 00000fff CR0=80050033 CR2=0000000000000000 CR3=000000002960a001 CR4=00760ef0 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=00000000fffe0ff0 DR7=0000000000000400 EFER=0000000000000d01 Code=dc 60 4e 00 4c 89 e0 41 5c 5d c3 0f 1f 44 00 00 89 f0 89 f9 <0f> 30 31 c0 0f 1f 44 00 00 c3 55 48 c1 e2 20 89 f6 48 09 d6 89 c2 48 89 e5 48 83 ec 08 89 > --- > arch/x86/kvm/emulate.c | 7 +++++-- > arch/x86/kvm/x86.c | 6 +++++- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 1d450d7710d63..d855304f5a509 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -3702,13 +3702,16 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt) > static int em_wrmsr(struct x86_emulate_ctxt *ctxt) > { > u64 msr_data; > + int ret; > > msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX) > | ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32); > - if (ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data)) > + > + ret = ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data); > + if (ret > 0) > return emulate_gp(ctxt, 0); > > - return X86EMUL_CONTINUE; > + return ret < 0 ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; > } > > static int em_rdmsr(struct x86_emulate_ctxt *ctxt) > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 063d70e736f7f..e4b07be450d4e 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1612,8 +1612,12 @@ int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu) > { > u32 ecx = kvm_rcx_read(vcpu); > u64 data = kvm_read_edx_eax(vcpu); > + int ret = kvm_set_msr(vcpu, ecx, data); > > - if (kvm_set_msr(vcpu, ecx, data)) { > + if (ret < 0) > + return ret; > + > + if (ret > 0) { > trace_kvm_msr_write_ex(ecx, data); > kvm_inject_gp(vcpu, 0); > return 1;