From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZpeQV5yGxAF/Zv9HFZSKGDe/r26W2unPAeEMqIaDCPzT7KSeNNol9foWmUFZb63SBBGja6X ARC-Seal: i=1; a=rsa-sha256; t=1526937407; cv=none; d=google.com; s=arc-20160816; b=bLLlFVbNKRQatC/FrByUSvjr6XGIElrfzLNy/t4HRgbhOrBYWCpPlezbg9hzpkh0fs pBnoaN3uTrstuCCSa+brJ1SdP3vmjdtn/K37KSJvAeEVsW56fVf89DpxoOyh8ebRd5o8 XHyGOH+2LfF7xcVoVLQ5lem67GDXY0ePNtWuLq19kk6KJBI1M7dUcHT6oiVZ7+GDv6Bx oytaVEAGrbcVMY4xrB9f+V/c2Cewg5j796kpg6effqC4JRz8xEj64ciqbT8mZA05qiYR rD1FXUdoqH9UgWYB9MX0kb40DuUf4qhWCPUNjCdCtu7vdH4Qfo8Jw/M7iWnJtz0KHOBp oX/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:arc-authentication-results; bh=5weaQz6fUylRZXfWmMnx616YKv0sxcFtsoZRCO+Q1Ns=; b=EpT9fh0W4cojwccxLEC1Un94Oat8Z4DEZNGEB7WSkvR1lBOOnlJnsCwibblAIbGVHN aL1goDa/bR5J4PsyaOXYI9zwMbk3iZqPctd/ZbXVCMZYdLktLDRDnqgGGPXkKVoCgPq2 bKanH3GTPoPY3EYgJ1oh688eeIWI/pE9gBwTDGRyajDStXZ+ZOHZXZ7dbDea9TrtDwrf oUFtg3dyHUy10zL+RIFy4snGWvbPTPqcQU3F1tYVo/CtKxjF9fpWTDkGUSm6uRK5y/CD D3//fgmKVCg6vM+vw1DKJM9nX/0HH/tLCzqej7OVYLuaHeEib26rU12iAk3GgZ2CLdxJ x/lQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=VGwZs1Sz; spf=pass (google.com: domain of srs0=nia/=ii=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=nia/=II=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=VGwZs1Sz; spf=pass (google.com: domain of srs0=nia/=ii=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=nia/=II=linuxfoundation.org=gregkh@kernel.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Borislav Petkov , Konrad Rzeszutek Wilk , Paolo Bonzini , David Woodhouse Subject: [PATCH 4.9 71/87] KVM: SVM: Move spec control call after restore of GS Date: Mon, 21 May 2018 23:11:47 +0200 Message-Id: <20180521210426.247329442@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180521210420.222671977@linuxfoundation.org> References: <20180521210420.222671977@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1601109918498873978?= X-GMAIL-MSGID: =?utf-8?q?1601109918498873978?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner commit 15e6c22fd8e5a42c5ed6d487b7c9fe44c2517765 upstream svm_vcpu_run() invokes x86_spec_ctrl_restore_host() after VMEXIT, but before the host GS is restored. x86_spec_ctrl_restore_host() uses 'current' to determine the host SSBD state of the thread. 'current' is GS based, but host GS is not yet restored and the access causes a triple fault. Move the call after the host GS restore. Fixes: 885f82bfbc6f x86/process: Allow runtime control of Speculative Store Bypass Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Reviewed-by: Konrad Rzeszutek Wilk Acked-by: Paolo Bonzini Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5011,6 +5011,18 @@ static void svm_vcpu_run(struct kvm_vcpu #endif ); + /* Eliminate branch target predictions from guest mode */ + vmexit_fill_RSB(); + +#ifdef CONFIG_X86_64 + wrmsrl(MSR_GS_BASE, svm->host.gs_base); +#else + loadsegment(fs, svm->host.fs); +#ifndef CONFIG_X86_32_LAZY_GS + loadsegment(gs, svm->host.gs); +#endif +#endif + /* * We do not use IBRS in the kernel. If this vCPU has used the * SPEC_CTRL MSR it may have left it on; save the value and @@ -5031,18 +5043,6 @@ static void svm_vcpu_run(struct kvm_vcpu x86_spec_ctrl_restore_host(svm->spec_ctrl); - /* Eliminate branch target predictions from guest mode */ - vmexit_fill_RSB(); - -#ifdef CONFIG_X86_64 - wrmsrl(MSR_GS_BASE, svm->host.gs_base); -#else - loadsegment(fs, svm->host.fs); -#ifndef CONFIG_X86_32_LAZY_GS - loadsegment(gs, svm->host.gs); -#endif -#endif - reload_tss(vcpu); local_irq_disable();