From nobody Wed Feb 11 01:27:28 2026 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 7F039288C0E for ; Tue, 13 Jan 2026 00:30:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768264250; cv=none; b=dDrbNPvfzNgpq5wGbzxtZPxjobmH+I1p4HDYv3TEa0Hjw49X8BrW5Fcd6cT1m/Qg/+lFqHZoF1CuVq3Olt22EosS+ppQIL7HYU/CeAi1Cmtu2UN7/AS1s5YV6L6t2EsqF8WFsbjOYmkw9qHtGVaA7Entq/K063ujCqBCJF0FpHE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768264250; c=relaxed/simple; bh=GXNfsZodxJg18lIVOowWLOQoXl4JDdLPRWwv0h+oAGg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=UcrJNwawgu84xf11RSw49qU47mAZM/cZmuQhkAIuykY/UIPHee5dPq/zcUKq94E4ssMAKe5BcOYzyasJZl4GrkUz7ea0NjU565c9NvrffsxLk/H5go1XfTTkB56qTgiA/Ehf0AvzEAXTtwykGUBtVy3OaSpOqC/4rTpuTDyVJE8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jmattson.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=WiRo5sbL; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jmattson.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WiRo5sbL" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-34abd303b4aso14221001a91.1 for ; Mon, 12 Jan 2026 16:30:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1768264248; x=1768869048; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=0BxdR1vY6NdM1JiLZatN+UvPHxnxGanJUBcgu7o+uIY=; b=WiRo5sbLe/QeNo75WnxGMf8App4wa0u+6MCzq41PgiKeaB1FH3xf/wxM15+wJhhlUJ 7J5sKH96zvyaVK+zw6ru7Xe57x8ph/v0hrmnYbY9x3h1tspdDoyJIGemq1NJsScThkfY w+ikfcuZxqU+8e1u7aKFJ15/Eq4kPcClD2OxyzpDzwzvRoruCjDBgoGsOiCZXOCO+OMu 7QeYuhR1c5v4d5t/M0DxAwGoEhu6GbhviCQYwJZiGTDQ4q59Lp+Xu/YBHGRwU70sSzaC k7rhCV0l78UtjU9CNNPKxJnVzkbIS81CPsVLWFuFXY3UuilFrpNOIkn++cLSr/AyY/u7 WoQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768264248; x=1768869048; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=0BxdR1vY6NdM1JiLZatN+UvPHxnxGanJUBcgu7o+uIY=; b=k+woXFRRCgbc6Jhi9+zm4kzXe/WI6hZHNG/gJdmTMchSdzklqtjGUXzGd9eJBs+ID9 MTwrwcuEwV4fx5vNc+Ylgd9OHcJ/zAzoXkOi8OjGrMeW4L+ppn2hdPne+V6TVYhPAL1E 25JxFBvNach9ex14y4c5Lh3zDmtMHf+qpPuAWlesIn0FOZfbpdrNvasFBnST1jrdbtGg mpjxSBRLUUySADvAogNSov5QM8MSZDd6GJ65vyaMzYKRhGuxAhfsNey9ezG+xNeUIjRz Q3LDzt/DVmKio9uOHRSbJt6aEZxhNnTJYzFaRX12oFj+RXwb7QCPHBpbctVuGJoS778q KIeg== X-Forwarded-Encrypted: i=1; AJvYcCV14NL1WonmzElRkx2qqFBVDJyB3tmvAC6Zp7yoPNdlf7sFA9BFyjg7SqboqK2VACh5Q4pnW/gjndPJqj4=@vger.kernel.org X-Gm-Message-State: AOJu0Yzcu3t1ORuxvArBE9KcIOauK4bdM81hkV5yqdOns1kHB+Z+WR+W 7FuYNyUYBgLwxcBHkOMNiffaUgMOF+HFLmpGjhVkGNcnhqapd6J77WR6SQvqTBCfbsYZkmNiq+G xmEQ30lxry5q0Xw== X-Google-Smtp-Source: AGHT+IHe5+A3CkmMwfa6NX/c/y3dmZRsvN4fz2G+7h6Oyq2lMwLT16xSzZnTnDPJSkfFMjPIdXJMlR/jIYa48w== X-Received: from pjok19.prod.google.com ([2002:a17:90a:9113:b0:34c:5a1b:47fb]) (user=jmattson job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5708:b0:340:bde5:c9e8 with SMTP id 98e67ed59e1d1-34f68cbe5c9mr16431579a91.22.1768264247741; Mon, 12 Jan 2026 16:30:47 -0800 (PST) Date: Mon, 12 Jan 2026 16:30:03 -0800 In-Reply-To: <20260113003016.3511895-1-jmattson@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260113003016.3511895-1-jmattson@google.com> X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog Message-ID: <20260113003016.3511895-9-jmattson@google.com> Subject: [PATCH 08/10] KVM: x86: nSVM: Save gPAT to vmcb12.g_pat on emulated #VMEXIT from L2 to L1 From: Jim Mattson To: Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Shuah Khan , Joerg Roedel , Avi Kivity , Alexander Graf , "=?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?=" , David Hildenbrand , Cathy Avery , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Jim Mattson Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" According to the APM volume 3 pseudo-code for "VMRUN," when nested paging is enabled in the VMCB, the guest PAT register (gPAT) is saved to the VMCB on #VMEXIT. KVM doesn't implement a separate gPAT register. Instead, the guest PAT is stored in the IA32_PAT MSR while in guest mode (L2) and nested NPT is enabled in vmcs02. Save the current IA32_PAT MSR to the vmcb12 g_pat field on emulated #VMEXIT from L2 to L1. Fixes: 15038e147247 ("KVM: SVM: obey guest PAT") Signed-off-by: Jim Mattson --- arch/x86/kvm/svm/nested.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 90edea73ec58..5fbe730d4c69 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1197,6 +1197,15 @@ int nested_svm_vmexit(struct vcpu_svm *svm) vmcb12->save.dr6 =3D svm->vcpu.arch.dr6; vmcb12->save.cpl =3D vmcb02->save.cpl; =20 + /* + * KVM stores the guest PAT in the IA32_PAT register while in + * guest mode with nested NPT enabled (rather than in a + * separate G_PAT register). Hence, the IA32_PAT MSR is stored + * in the VMCB12 g_pat field on #VMEXIT. + */ + if (nested_npt_enabled(svm)) + vmcb12->save.g_pat =3D vcpu->arch.pat; + if (guest_cpu_cap_has(vcpu, X86_FEATURE_SHSTK)) { vmcb12->save.s_cet =3D vmcb02->save.s_cet; vmcb12->save.isst_addr =3D vmcb02->save.isst_addr; --=20 2.52.0.457.g6b5491de43-goog