From nobody Thu Apr 2 01:54:02 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 CDEA93A4513 for ; Fri, 27 Mar 2026 23:40:42 +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=1774654844; cv=none; b=hciMVoLNUnXb02XUckzgyiej1YhNxMgo1/tjojeIDcATcDaG35+F280KKkSBFRTB5PxuE2B+a0myhBoO4AcK1EFFVWJH59m8FeNy9w7UiYnk6TCuzqvhoZJDvbPnsWmoBiKWZ6OrfVelZRNc8314iWhSsHAvXud2/neurOq7k3E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774654844; c=relaxed/simple; bh=ZvxNNPnPmX7wYJVvYk5hMj+puG16Eo/l6nqfvIOJDnw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=O/nSJsbBYT5RcozqeS7STVHC+e5iSAAXRCMHvUL80u+MYq8dTVasCfOlMyXGB+WSS60f7sSBZ1u7lFDVOcK67jZpGhrZ66R4L2EbKU1kyrxOsIPnUDYDU/WALqnhY0L5yOOQEyCLC73CYujpwX11R7MAQMMDU/gHfj/zGPQRqt8= 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=tmojgP9e; 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="tmojgP9e" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-35d9467e85aso158196a91.0 for ; Fri, 27 Mar 2026 16:40:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774654842; x=1775259642; 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=orVw3BFMtlEwOndHFsmUNVe5beJCJOsEnJ6vfIk60cg=; b=tmojgP9emI4mtKMvbsMYALuTLkpyDtr+5liMbtyFjUHERstqna5BwJQyH7RlEo/rg2 sY8OwbruhsXDA8aKgDicW/maKTxaFD+/CvoDkL/JNnXDWjDyt/Ij6Az7c9XHJ3/f7gv6 NhNRtlKtcs0WOhC8SkfI7FFw6FHmWzPK6zDXE1JKco+wlLBjRwwo3iOCH8Mztte/P3Xr aIraqNHgz/m+oV0IC1AJj679/clAN+wP2gAaxIU9dEGH4vTvvr06LS8cOgiON6D1bovU bz/T2T47SWqkKFNCSF7nEHFcRbNkl7NtVrPzLrKVqxZved/uQYbm21IYR5tfPeYZlt+W QnOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774654842; x=1775259642; 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=orVw3BFMtlEwOndHFsmUNVe5beJCJOsEnJ6vfIk60cg=; b=TN8ot/KxHp3tH22+TVK9sQ3etnHbz66oFm3vOhEJ+6lRAjhAj7O9yZI5FlcnzHaJoT LCqjlmDsVh3u0ITMnMOt5ZT26lrB+OHRIuAmBkTqkkx6Rb9JW4MAO1eBBj+klVA8zMYQ sa1w27lDYVoPAzYCf7nwCu1fAySu5k00BPnsh70g1NWFNGGE87K927ROTjbYeO+pe3Z9 tAlXLMNITaGr6JMy9PYBwtG//FXxvQ/cveFo4OXyQFoYsa2Xg+LetpQDdqRwWe7eIk8C gu145N6/V+7ZO0kvztC/ESvkcwosIPbheU1YghvMv8vPNlePGcFQMqyrzCBB2oTNeta4 LkWw== X-Forwarded-Encrypted: i=1; AJvYcCVRi/4T0mRtz4PL30kf1t3l52TCjZg+Ub33mOo5UlavQdqg7nvlL/AzsszEzmhbp6gF+KTTLWwQtADwXZs=@vger.kernel.org X-Gm-Message-State: AOJu0YzQmeF2qFEadZuVBpfnId7NuIg4QF13kUV+Yb3w4Msuztmc773/ nzW5VIDP9du0xltqG6dtlWCA4dKUwOjaO+oc5WXuqt4+w8svdgmjO/UL1XyEXKTOFnIk2b7HvUb yff823ZynpnoBzg== X-Received: from pjur6.prod.google.com ([2002:a17:90a:d406:b0:35c:251c:2305]) (user=jmattson job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:d44d:b0:35b:e4f8:7cc5 with SMTP id 98e67ed59e1d1-35c300b9405mr3788148a91.25.1774654841889; Fri, 27 Mar 2026 16:40:41 -0700 (PDT) Date: Fri, 27 Mar 2026 16:40:15 -0700 In-Reply-To: <20260327234023.2659476-1-jmattson@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260327234023.2659476-1-jmattson@google.com> X-Mailer: git-send-email 2.53.0.1018.g2bb0e51243-goog Message-ID: <20260327234023.2659476-9-jmattson@google.com> Subject: [PATCH v7 8/9] KVM: x86: nSVM: Save/restore gPAT with KVM_{GET,SET}_NESTED_STATE From: Jim Mattson To: Paolo Bonzini , Jonathan Corbet , Shuah Khan , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Yosry Ahmed Cc: Jim Mattson Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a 'gpat' field to kvm_svm_nested_state_hdr to carry L2's guest PAT value across save and restore. When KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT is disabled and the vCPU is in guest mode with nested NPT enabled, save vmcb02's g_pat into the header on KVM_GET_NESTED_STATE, and restore it on KVM_SET_NESTED_STATE. Host-initiated accesses to IA32_PAT (via KVM_GET/SET_MSRS) always target L1's hPAT, so they cannot be used to save or restore gPAT. The separate header field ensures that KVM_GET/SET_MSRS and KVM_GET/SET_NESTED_STATE are independent and can be ordered arbitrarily during save and restore. Note that struct kvm_svm_nested_state_hdr is included in a union padded to 120 bytes, so there is room to add the gpat field without changing any offsets. Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET= _NESTED_STATE") Signed-off-by: Jim Mattson --- Documentation/virt/kvm/api.rst | 1 + arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/kvm/svm/nested.c | 20 ++++++++++++++++++++ 3 files changed, 22 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 0a2d873ca5a3..d6bbb7bad173 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4965,6 +4965,7 @@ Errors: =20 struct kvm_svm_nested_state_hdr { __u64 vmcb_pa; + __u64 gpat; }; =20 struct kvm_vmx_nested_state_data { diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kv= m.h index 3ada2fa9ca86..1585ec804066 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -533,6 +533,7 @@ struct kvm_svm_nested_state_data { =20 struct kvm_svm_nested_state_hdr { __u64 vmcb_pa; + __u64 gpat; }; =20 /* for KVM_CAP_NESTED_STATE */ diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index add57f2a2d9f..54399e642745 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1865,6 +1865,9 @@ static int svm_get_nested_state(struct kvm_vcpu *vcpu, /* First fill in the header and copy it out. */ if (is_guest_mode(vcpu)) { kvm_state.hdr.svm.vmcb_pa =3D svm->nested.vmcb12_gpa; + kvm_state.hdr.svm.gpat =3D 0; + if (l2_has_separate_pat(svm)) + kvm_state.hdr.svm.gpat =3D svm->vmcb->save.g_pat; kvm_state.size +=3D KVM_STATE_NESTED_SVM_VMCB_SIZE; kvm_state.flags |=3D KVM_STATE_NESTED_GUEST_MODE; =20 @@ -1918,6 +1921,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, struct vmcb_save_area_cached save_cached; struct vmcb_ctrl_area_cached ctl_cached; unsigned long cr0; + bool use_separate_l2_pat; int ret; =20 BUILD_BUG_ON(sizeof(struct vmcb_control_area) + sizeof(struct vmcb_save_a= rea) > @@ -1993,6 +1997,18 @@ static int svm_set_nested_state(struct kvm_vcpu *vcp= u, !nested_vmcb_check_save(vcpu, &save_cached, false)) goto out_free; =20 + /* + * Validate gPAT when the shared PAT quirk is disabled (i.e. L2 + * has its own gPAT). This is done separately from the + * vmcb_save_area_cached validation above, because gPAT is L2 + * state, but the vmcb_save_area_cached is populated with L1 state. + */ + use_separate_l2_pat =3D + (ctl_cached.misc_ctl & SVM_MISC_ENABLE_NP) && + !kvm_check_has_quirk(vcpu->kvm, + KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT); + if (use_separate_l2_pat && !kvm_pat_valid(kvm_state->hdr.svm.gpat)) + goto out_free; =20 /* * All checks done, we can enter guest mode. Userspace provides @@ -2017,6 +2033,10 @@ static int svm_set_nested_state(struct kvm_vcpu *vcp= u, nested_copy_vmcb_control_to_cache(svm, ctl); =20 svm_switch_vmcb(svm, &svm->nested.vmcb02); + + if (use_separate_l2_pat) + vmcb_set_gpat(svm->vmcb, kvm_state->hdr.svm.gpat); + nested_vmcb02_prepare_control(svm); =20 /* --=20 2.53.0.1018.g2bb0e51243-goog