From nobody Wed Dec 17 14:38:13 2025 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 464BFCDB483 for ; Wed, 18 Oct 2023 19:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231536AbjJRTlS (ORCPT ); Wed, 18 Oct 2023 15:41:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231621AbjJRTlN (ORCPT ); Wed, 18 Oct 2023 15:41:13 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF19B95 for ; Wed, 18 Oct 2023 12:41:11 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5a81a80097fso96092987b3.3 for ; Wed, 18 Oct 2023 12:41:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697658071; x=1698262871; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=Ofuuq8OnXnBwuNBiWtVLb1NEzqrH7XwtOSMnrh73sd8=; b=KQUyfewpiZDgHKhuBlxHffQ0dmFuq14bplh/X97tRzsZ1J4IVFw9LgSRusq4uePP7p I2fWrJB20gGOcn5OK3sPVx1Cws82eApx0yayMcRBTHMuag8ieLn/2rpiqGl3vYU4HPMP plDRDLUy8748Fghanx4KRrDiuZHDMRky8F4wOa8TUtlosUPPrnt8TW2Km2mHMOe1rfJT aNFAX76iUsrGF5vygVrg4yh/zpC/grDHqg9iEFeZfNT7U1Y0o/YXZDFBZvUTTCpBtV2t ZuO/MR0PUS/H22Pu5+Tp47+t0h+q8nJwrIqvaJ1iEY8W14kWB6immkZlwC+AABSEmehm PINg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697658071; x=1698262871; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Ofuuq8OnXnBwuNBiWtVLb1NEzqrH7XwtOSMnrh73sd8=; b=YheTq6Hs+gORztHMIZLrnMW8TX763146xm+ac8jhjLLSbVeWh1vn5nZRuYlt9eokZx 8GtpTviwlALLQKoJ2xcmQjKbRJeitqvsRM7ueAc6rZr7jJ5YkhzuUz6xXivTR0e/LK7E aOjszPynv6eUrgG0pwWQaUBit0jITugfgLV4abI3Fbbnrstx9wmWGnmACxWrlCnGbqBk vVBTRHXdCV8Wdavk2JAHW8nVt/dTcXWZLDMSCNqFk5OPmw60fbrLlRmQAbFLzeYrnQwV Qe3FezSoyA8O7KV4HWXWahXTjCkqqaxLPOw4Kp5F5IoNq0NoiRbyNNwYJ8dj1y3WDtdm xu0A== X-Gm-Message-State: AOJu0YxCMKXIyG2tXBvna2XsShNIkoEFRiuCAMl9zdVoutVJdpWINAZn d+1hYSmwVnj5222JpCT3c6dzfKJ12EA= X-Google-Smtp-Source: AGHT+IGW0vvt2l55+JL2+bM3VOgMoxB7qvHv720MxhQbccRQ4nqpX0a4NV57+RPdy39vplncxaNMVHs5grk= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1825:b0:d9a:d272:ee58 with SMTP id cf37-20020a056902182500b00d9ad272ee58mr7884ybb.9.1697658071068; Wed, 18 Oct 2023 12:41:11 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 18 Oct 2023 12:41:04 -0700 In-Reply-To: <20231018194104.1896415-1-seanjc@google.com> Mime-Version: 1.0 References: <20231018194104.1896415-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.655.g421f12c284-goog Message-ID: <20231018194104.1896415-3-seanjc@google.com> Subject: [PATCH 2/2] KVM: nSVM: Advertise support for flush-by-ASID From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Sterz Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Advertise support for FLUSHBYASID when nested SVM is enabled, as KVM can always emulate flushing TLB entries for a vmcb12 ASID, e.g. by running L2 with a new, fresh ASID in vmcb02. Some modern hypervisors, e.g. VMWare Workstation 17, require FLUSHBYASID support and will refuse to run if it's not present. Punt on proper support, as "Honor L1's request to flush an ASID on nested VMRUN" is one of the TODO items in the (incomplete) list of issues that need to be addressed in order for KVM to NOT do a full TLB flush on every nested SVM transition (see nested_svm_transition_tlb_flush()). Reported-by: Stefan Sterz Closes: https://lkml.kernel.org/r/b9915c9c-4cf6-051a-2d91-44cc6380f455%40pr= oxmox.com Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky --- arch/x86/kvm/svm/svm.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 1785de7dc98b..9cf7eef161ff 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5083,6 +5083,7 @@ static __init void svm_set_cpu_caps(void) if (nested) { kvm_cpu_cap_set(X86_FEATURE_SVM); kvm_cpu_cap_set(X86_FEATURE_VMCBCLEAN); + kvm_cpu_cap_set(X86_FEATURE_FLUSHBYASID); =20 if (nrips) kvm_cpu_cap_set(X86_FEATURE_NRIPS); --=20 2.42.0.655.g421f12c284-goog