From nobody Wed Oct 1 22:33:17 2025 Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 228AC19C553 for ; Fri, 26 Sep 2025 13:52:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758894724; cv=none; b=j2BA/8bSmm4dABDL08EAz7C85Io98a8ccARAiHwFzFMYrpYoqNpXLN7aFGWFNV8Kk7BZlxAkTUdoHdWFwxNF1m1hCDKdojbjF8QadkxdrfHzWpnxz0ofVrJAqzCooERPBqh/9pxrv/9BkThDLTGt+wmbjBvau5w+p9r2x8ZPVmE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758894724; c=relaxed/simple; bh=1/AcT3Bc5vPs/LPilkpfToUOPoo+e1GCVcKYXLiJ3/0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=nW8ltGFVlcYrft4I89EsDScuXHkyBOdtdrDwY2Do1CrIXX806EvCgz74LoTsj3qQUW4aFvIDtoAN+RAMVgSTW9+l8UR0SVJaJjVPwgyWcZScg4piyUUJ66pT1RHWTu/4fyzRykRNLZiJwuKPuvw2ccaK6c8QvELcixWIxUVZQF4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=iYM5KcYW; arc=none smtp.client-ip=209.85.210.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="iYM5KcYW" Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-77dedf198d4so2817958b3a.0 for ; Fri, 26 Sep 2025 06:52:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1758894722; x=1759499522; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=k7jp8yLZxEobbpETqyfchAwVX2BSGTy6SZoafcKNw1g=; b=iYM5KcYWq1rw95VdkS3Grtnvv+decUgb5KXAijwT86y5yfJeSFXUBgVz72Yx20BaOg TPk0dv0NgW0odF65Rrh1vUNcofyVNM2m35tx0Y9lvOj7pGgnR+cfpIY6gDzPi9QTUXsq osmhIVlM0a0AEan7xRml9Jl6qwAw+P2GkJt6E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758894722; x=1759499522; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=k7jp8yLZxEobbpETqyfchAwVX2BSGTy6SZoafcKNw1g=; b=fh6WMOKH9f58HcGmbyguabziVB2wpppM0q0c4DoutDDO/3TjoZQCte8xu2XmaIgoYv edRv5hMCFSTXNinnWlZd+WNTWRt0+iRlCOXCEwi7WAzwu3+5bJsssZyG30mGSTRtuKT6 Up0oa2JTKjV6vkwJ62NBHyH1QDayG7NY1ArqyjHzY+5uFDVRiqDkAfv6yTf67mUNdeVB 9ruQcONmpOG4amlltjlOnqtXDYmBScAXRm/bX1fjYKvkTaHF7yg6RNXY8UmiuHsPgQUv 4iwDDROtM8+EdAFoodBEkpjj5ACpsEBXappoZQBjgs3IeiEeGUVhK+k1jMNYjTiCEOoQ pCmw== X-Forwarded-Encrypted: i=1; AJvYcCW7EecQdqb9NWwVu23fRmWXoulVZKnGZHeDlWB3eFmFqvg73kWLUYPF9sWx/5LdDR2yMSoNzfAf8nH+Kac=@vger.kernel.org X-Gm-Message-State: AOJu0YyU67xeNZUhOAMKX9QtLhCBWtXZ7yFsJ2z4KuNlxyt7u70lwUfm 2Ajbe7KUFL5WeXerxxol4+7M2198Bp7Sq/Sn6cR8b1o4q9aKlbAlaW9PyBbyYadBBQ== X-Gm-Gg: ASbGncu+j2f2pduvuNr8UELL59vcFvRUnl8k4eVUv931njew4fOm9PyAw+TgVn8eKf0 qlocRkSeqDSiCsS1PSZ++ORbU671/rD9evvIYx6ssV9spmk6t/f4DPMiUrOAQ2ri4FSLzHucRN3 +b0jHzNYrgh2xxiupRULlhPB376ivz1JiICdR2o+6vgOJqTR6xPWksqSnT1YtqxYFxiCUoHbCRE opzOXNbk7kQpiF3dHqiePu6agfdVrOurg71zYZwtjMkyA/ekpHt6pBGQbo+LA6jzyJtLq5xiFpo OnOu/I6a+lxV1lcEhX1LccYPYwnVa3U+PrQwedBJw5eeXyaqqZNkWVHgpVwp8z52yq5VaGMBnxX eXhJx0sGcCFyG+Jw/gx3m6Q== X-Google-Smtp-Source: AGHT+IHkScieu2EQ5+BzeIwXjQ+6+pWTvDLXaL7ksD8U1FVF/quB9UFR7FpLBLPhA3BlkAgBp75jfQ== X-Received: by 2002:a17:90a:be0b:b0:332:8133:b377 with SMTP id 98e67ed59e1d1-3342a280378mr8184201a91.15.1758894722418; Fri, 26 Sep 2025 06:52:02 -0700 (PDT) Received: from dmaluka1.corp.google.com ([2a00:79e0:a:200:f83f:a8ff:c4f3:beb]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-334352935d3sm2657143a91.3.2025.09.26.06.51.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Sep 2025 06:52:02 -0700 (PDT) From: Dmytro Maluka To: kvm@vger.kernel.org, Sean Christopherson , Paolo Bonzini Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org, Grzegorz Jaszczyk , Vineeth Pillai , Tomasz Nowicki , Chuanxiao Dong , Dmytro Maluka Subject: [PATCH] KVM: x86/mmu: Skip MMIO SPTE invalidation if enable_mmio_caching=0 Date: Fri, 26 Sep 2025 15:51:39 +0200 Message-ID: <20250926135139.1597781-1-dmaluka@chromium.org> X-Mailer: git-send-email 2.51.0.536.g15c5d4f767-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If MMIO caching is disabled, there are no MMIO SPTEs to invalidate, so the costly zapping of all pages is unnecessary even in the unlikely case when the MMIO generation number has wrapped. Signed-off-by: Dmytro Maluka --- arch/x86/kvm/mmu/mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6e838cb6c9e1..bad613e8fa95 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -7339,6 +7339,9 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u= 64 gen) { WARN_ON_ONCE(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS); =20 + if (!enable_mmio_caching) + return; + gen &=3D MMIO_SPTE_GEN_MASK; =20 /* --=20 2.51.0.536.g15c5d4f767-goog