From patchwork Tue Apr 16 20:19:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13632540 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6E91139D16 for ; Tue, 16 Apr 2024 20:19:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713298783; cv=none; b=OQQXXIXQQdADUSfY7RYAMyfkoT+TsTEWY38mjDQtNh4qAD6BoILV5bjra56JKX9eYMoTWAAhGC2yWfvDujd8oU/ctz1RyHlxNNpL5AsmmyfiDwDNMty5VDoNgvgq6yVvM7itvasmaXspg0mObGDtYrf56BIUu4ro1fFl+XVuleM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713298783; c=relaxed/simple; bh=zrMK1CJms/6SL5AG7A6aHU0z1D+fasw9+uRPwXvEGDk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Mqo1E7vOgtu86+o7jHQGNGO497zqwsse05M8n2LnQln29NDqHN0hbbzch/O52zQXyyvjotcC0yQfoHKXakfqVTCLf+v2NpaqilFUIHr+ZzEG4YCopxMywHs3YmnokMZPmB4A06GSt/UOoegnwT3RYGuV6j+d8VPJcjjujIJRz+A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ZHsZ+cjz; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZHsZ+cjz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1713298780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2/otD1VSzsXz9/d/LXuHnyGMpoSGECP95q0JyJeR82U=; b=ZHsZ+cjzEFbEyLpgMNYg2VT5bjeIoNgabypscgcfMY00wDucDutaQ/2OEcG27ToO9CYMu7 n9UChLQ3y3sNTKf6BrRQBY8hBEmBdV9aH6O7vrf5dgi1v+vFDxH8hXVFzjvAhOzzoOtlR9 NeAJ1N1WkZc1vU1P1KYMBJeDeKkPFI4= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-295-o_uHjzYfNPCnc4WUWZ8qJw-1; Tue, 16 Apr 2024 16:19:37 -0400 X-MC-Unique: o_uHjzYfNPCnc4WUWZ8qJw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 210811C05149; Tue, 16 Apr 2024 20:19:37 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id E51B54910B; Tue, 16 Apr 2024 20:19:36 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: isaku.yamahata@intel.com, xiaoyao.li@intel.com, binbin.wu@linux.intel.com, chao.gao@intel.com, Sean Christopherson Subject: [PATCH v2 02/10] KVM: x86/mmu: Replace hardcoded value 0 for the initial value for SPTE Date: Tue, 16 Apr 2024 16:19:27 -0400 Message-ID: <20240416201935.3525739-3-pbonzini@redhat.com> In-Reply-To: <20240416201935.3525739-1-pbonzini@redhat.com> References: <20240416201935.3525739-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 From: Sean Christopherson The TDX support will need the "suppress #VE" bit (bit 63) set as the initial value for SPTE. To reduce code change size, introduce a new macro SHADOW_NONPRESENT_VALUE for the initial value for the shadow page table entry (SPTE) and replace hard-coded value 0 for it. Initialize shadow page tables with their value. The plan is to unconditionally set the "suppress #VE" bit for both AMD and Intel as: 1) AMD hardware uses the bit 63 as NX for present SPTE and ignored for non-present SPTE; 2) for conventional VMX guests, KVM never enables the "EPT-violation #VE" in VMCS control and "suppress #VE" bit is ignored by hardware. No functional change intended. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata Message-Id: [Remove unnecessary CONFIG_X86_64 check. - Paolo] Reviewed-by: Xiaoyao Li Reviewed-by: Binbin Wu Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/mmu.c | 14 +++++++++----- arch/x86/kvm/mmu/paging_tmpl.h | 2 +- arch/x86/kvm/mmu/spte.h | 4 +++- arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++------ 4 files changed, 19 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 08900a0563f9..fbfdc606f1f1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -567,9 +567,9 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) if (!is_shadow_present_pte(old_spte) || !spte_has_volatile_bits(old_spte)) - __update_clear_spte_fast(sptep, 0ull); + __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE); else - old_spte = __update_clear_spte_slow(sptep, 0ull); + old_spte = __update_clear_spte_slow(sptep, SHADOW_NONPRESENT_VALUE); if (!is_shadow_present_pte(old_spte)) return old_spte; @@ -603,7 +603,7 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep) */ static void mmu_spte_clear_no_track(u64 *sptep) { - __update_clear_spte_fast(sptep, 0ull); + __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE); } static u64 mmu_spte_get_lockless(u64 *sptep) @@ -1897,7 +1897,8 @@ static bool kvm_sync_page_check(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) static int kvm_sync_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int i) { - if (!sp->spt[i]) + /* sp->spt[i] has initial value of shadow page table allocation */ + if (sp->spt[i] == SHADOW_NONPRESENT_VALUE) return 0; return vcpu->arch.mmu->sync_spte(vcpu, sp, i); @@ -6120,7 +6121,10 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; - vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_shadow_page_cache.init_value = + SHADOW_NONPRESENT_VALUE; + if (!vcpu->arch.mmu_shadow_page_cache.init_value) + vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 4d4e98fe4f35..bebd73cd61bb 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -911,7 +911,7 @@ static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int gpa_t pte_gpa; gfn_t gfn; - if (WARN_ON_ONCE(!sp->spt[i])) + if (WARN_ON_ONCE(sp->spt[i] == SHADOW_NONPRESENT_VALUE)) return 0; first_pte_gpa = FNAME(get_level1_sp_gpa)(sp); diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index f5c600c52f83..0f4ec2859474 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -149,6 +149,8 @@ static_assert(MMIO_SPTE_GEN_LOW_BITS == 8 && MMIO_SPTE_GEN_HIGH_BITS == 11); #define MMIO_SPTE_GEN_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_BITS + MMIO_SPTE_GEN_HIGH_BITS - 1, 0) +#define SHADOW_NONPRESENT_VALUE 0ULL + extern u64 __read_mostly shadow_host_writable_mask; extern u64 __read_mostly shadow_mmu_writable_mask; extern u64 __read_mostly shadow_nx_mask; @@ -194,7 +196,7 @@ extern u64 __read_mostly shadow_nonpresent_or_rsvd_mask; * * Only used by the TDP MMU. */ -#define REMOVED_SPTE 0x5a0ULL +#define REMOVED_SPTE (SHADOW_NONPRESENT_VALUE | 0x5a0ULL) /* Removed SPTEs must not be misconstrued as shadow present PTEs. */ static_assert(!(REMOVED_SPTE & SPTE_MMU_PRESENT_MASK)); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index c6192a52bd31..f5401967897a 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -603,7 +603,7 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm, * here since the SPTE is going from non-present to non-present. Use * the raw write helper to avoid an unnecessary check on volatile bits. */ - __kvm_tdp_mmu_write_spte(iter->sptep, 0); + __kvm_tdp_mmu_write_spte(iter->sptep, SHADOW_NONPRESENT_VALUE); return 0; } @@ -740,8 +740,8 @@ static void __tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root, continue; if (!shared) - tdp_mmu_iter_set_spte(kvm, &iter, 0); - else if (tdp_mmu_set_spte_atomic(kvm, &iter, 0)) + tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE); + else if (tdp_mmu_set_spte_atomic(kvm, &iter, SHADOW_NONPRESENT_VALUE)) goto retry; } } @@ -808,8 +808,8 @@ bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) if (WARN_ON_ONCE(!is_shadow_present_pte(old_spte))) return false; - tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, 0, - sp->gfn, sp->role.level + 1); + tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, + SHADOW_NONPRESENT_VALUE, sp->gfn, sp->role.level + 1); return true; } @@ -843,7 +843,7 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root, !is_last_spte(iter.old_spte, iter.level)) continue; - tdp_mmu_iter_set_spte(kvm, &iter, 0); + tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE); /* * Zappings SPTEs in invalid roots doesn't require a TLB flush,