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 34262EE49A6 for ; Mon, 21 Aug 2023 01:19:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232305AbjHUBTg (ORCPT ); Sun, 20 Aug 2023 21:19:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232273AbjHUBTb (ORCPT ); Sun, 20 Aug 2023 21:19:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E51D8A0 for ; Sun, 20 Aug 2023 18:19:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7719C62600 for ; Mon, 21 Aug 2023 01:19:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72EF5C433C7; Mon, 21 Aug 2023 01:19:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692580768; bh=DW3Rkm64vuwtwMBbIqCA2GpSEy3gnsoalKuEuFJJaWA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rXszqG9hnuzM5B5aORpcJM5tFbtP47DwlBt7MX4jqQcPs1Vi0T7hd151utynjdkf8 P+TF4obMZ7dlEgLmkl5eh+zDf/ySNWvOmoCauwHrJ0ZL55i9Yo8xLvzsEpdO32RY/k oCzenoJe+M77+MIVT+m0McZil227wB+kjSqQZGne3I93oqWuqan16w2/9jHwf5kiFP Wj9oK3wXDHuL/QDHs+9XXwhs1az1c+HWXtojP8LXX2tjNk7ISgBBYTPiHX3U0wgdt6 HrxwmiIqoesxLDA942+qurp0XondanfqJTFPyad0g1WH5FRMBsRHyM6IEejydodvVl bcW9O0sdSQ5iw== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Borislav Petkov , Peter Zijlstra , Babu Moger , Paolo Bonzini , Sean Christopherson , David.Kaplan@amd.com, Andrew Cooper , Nikolay Borisov , gregkh@linuxfoundation.org, Thomas Gleixner Subject: [PATCH 03/22] KVM: x86: Support IBPB_BRTYPE and SBPB Date: Sun, 20 Aug 2023 18:19:00 -0700 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The IBPB_BRTYPE and SBPB CPUID bits aren't set by HW. >From the AMD SRSO whitepaper: "Hypervisor software should synthesize the value of both the IBPB_BRTYPE and SBPB CPUID bits on these platforms for use by guest software." These bits are already set during kernel boot. Manually propagate them to the guest. Also, propagate PRED_CMD_SBPB writes. Signed-off-by: Josh Poimboeuf --- arch/x86/kvm/cpuid.c | 4 ++++ arch/x86/kvm/x86.c | 9 +++++---- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d3432687c9e6..cdf703eec42d 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -729,6 +729,10 @@ void kvm_set_cpu_caps(void) F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */ ); + if (cpu_feature_enabled(X86_FEATURE_SBPB)) + kvm_cpu_cap_set(X86_FEATURE_SBPB); + if (cpu_feature_enabled(X86_FEATURE_IBPB_BRTYPE)) + kvm_cpu_cap_set(X86_FEATURE_IBPB_BRTYPE); if (cpu_feature_enabled(X86_FEATURE_SRSO_NO)) kvm_cpu_cap_set(X86_FEATURE_SRSO_NO); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c381770bcbf1..dd7472121142 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3676,12 +3676,13 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!msr_info->host_initiated && !guest_has_pred_cmd_msr(vcpu)) return 1; - if (!boot_cpu_has(X86_FEATURE_IBPB) || (data & ~PRED_CMD_IBPB)) + if (boot_cpu_has(X86_FEATURE_IBPB) && data == PRED_CMD_IBPB) + wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB); + else if (boot_cpu_has(X86_FEATURE_SBPB) && data == PRED_CMD_SBPB) + wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_SBPB); + else if (data) return 1; - if (!data) - break; - wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB); break; case MSR_IA32_FLUSH_CMD: if (!msr_info->host_initiated && -- 2.41.0