From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 42DEB35C69F for ; Fri, 18 Sep 2026 08:16:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789719369; cv=none; b=aRaRvAppF4RXdmdGaJXV7cOfZmiQ5Rw20zowerDUEr2kCc82QlWG3725p5gcgGK++G93r4XrVa++fND81jtoDgAPLY2jWgntbmFUX4wq6IUoJRCnwC2W0pDty/iOJ+EtW2v41YYggPE7Z0A5Jtmv6k2Y51rk8Wx+oXAbfUtBl20= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789719369; c=relaxed/simple; bh=0KSm60RmbVxBGC+ZwxwAp4zJAlyv12vvrsCfKg1n46o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=iCqcampJ2d/0w9gU/faWPAxEByjUSpHFJyCpjx5QtVLpW8vrL7FH+Ctbm8N7kcW1Pq+hSR1CQ0VKtjE+w/OdpKl+dEKkjoVy+j9/BG7uFXV0eJHQYEoGpvWIAVPXzRFsvMPSCndlvHevfVI9NnpEHWFrZZeka88ZG4hX9ySeiUU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=az+fRn0O; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="az+fRn0O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1789719360; 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=Ds2Lc+aMh2WymrMTxljwuJtfkBBHdr6kIvvoHFilRIs=; b=az+fRn0OmzUGN9kB3/jfDZgsol3ANDBiIikxl4dtzJOvzhGee8jHM4sOEN4kyuS4wF5b/3 5/pMamq9zYeHCgxFV4/VDiJI0uTUNVI7IzdUfc5s6lOp/w7G28q+ImN1K4ZMTedhmIxGZ7 5G63q0m9tRrh1mAxpqr4nJEOgqUgduQ= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-446-QK---mVANnWbuPIW32toZw-1; Fri, 18 Sep 2026 04:15:57 -0400 X-MC-Unique: QK---mVANnWbuPIW32toZw-1 X-Mimecast-MFC-AGG-ID: QK---mVANnWbuPIW32toZw_1789719356 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0F89318512C6; Fri, 18 Sep 2026 08:15:56 +0000 (UTC) Received: from virtlab1023.virt.eng.rdu2.dc.redhat.com (virtlab1023.virt.eng.rdu2.dc.redhat.com [10.18.48.26]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 64DAD30001A2; Fri, 18 Sep 2026 08:15:55 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: nsaenz@amazon.com, vkuznets@redhat.com, snambakam@linux.microsoft.com Subject: [PATCH v2 13/28] KVM: Include memory protections in result of gfn->hva conversion Date: Fri, 18 Sep 2026 04:15:28 -0400 Message-ID: <20260918081543.139871-14-pbonzini@redhat.com> In-Reply-To: <20260918081543.139871-1-pbonzini@redhat.com> References: <20260918081543.139871-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 From: Nicolas Saenz Julienne All paths that lead to guest memory accesses now need to check whether memory attributes allow that access. Users of gfn_to_hva, kvm_vcpu_gfn_to_hva and their *_prot variant can get it more or less for free via erroneous return values, so do this first. Note however that this is not true of the variants that take a cached kvm_memslots pointer. These include caches (gfn-to-hva and gfn-to-pfn) and page faults, both of which will need specific changes; but the more optimized functions in virt/kvm/kvm_main.c such as kvm_read_guest() and kvm_write_guest() also retrieve the memslot high in the call chain, and therefore they will need changes in __kvm_read/write_guest_page(). Signed-off-by: Nicolas Saenz Julienne Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 18 +++++++++++++ virt/kvm/kvm_main.c | 55 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 69 insertions(+), 4 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c215e3bdf043..01223301f0e5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2620,8 +2620,26 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) { return false; } +static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn) +{ + return 0; +} #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ +static inline int kvm_mem_attributes_may_read_gfn(struct kvm *kvm, gfn_t gfn) +{ + unsigned long attrs = kvm_get_memory_attributes(kvm, gfn); + + return kvm_mem_attributes_may_read(attrs); +} + +static inline int kvm_mem_attributes_may_write_gfn(struct kvm *kvm, gfn_t gfn) +{ + unsigned long attrs = kvm_get_memory_attributes(kvm, gfn); + + return kvm_mem_attributes_may_write(attrs); +} + #ifdef CONFIG_KVM_GUEST_MEMFD int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, struct page **page, diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index f98104169862..b1cc570be8df 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2767,13 +2767,38 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(gfn_to_hva_memslot); unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn) { - return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL); + unsigned long addr; + + addr = gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL); + if (kvm_is_error_hva(addr)) + return addr; + + if (!kvm_mem_attributes_may_read_gfn(kvm, gfn)) + return KVM_HVA_ERR_BAD; + + if (!kvm_mem_attributes_may_write_gfn(kvm, gfn)) + return KVM_HVA_ERR_RO_BAD; + + return addr; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(gfn_to_hva); unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn) { - return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL); + struct kvm *kvm = vcpu->kvm; + unsigned long addr; + + addr = gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL); + if (kvm_is_error_hva(addr)) + return addr; + + if (!kvm_mem_attributes_may_read_gfn(kvm, gfn)) + return KVM_HVA_ERR_BAD; + + if (!kvm_mem_attributes_may_write_gfn(kvm, gfn)) + return KVM_HVA_ERR_RO_BAD; + + return addr; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_gfn_to_hva); @@ -2799,15 +2824,37 @@ unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot, unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable) { struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); + unsigned long addr; - return gfn_to_hva_memslot_prot(slot, gfn, writable); + addr = gfn_to_hva_memslot_prot(slot, gfn, writable); + if (kvm_is_error_hva(addr)) + return addr; + + if (!kvm_mem_attributes_may_read_gfn(kvm, gfn)) + return KVM_HVA_ERR_BAD; + + if (writable && !kvm_mem_attributes_may_write_gfn(kvm, gfn)) + *writable = false; + + return addr; } unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable) { struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); + unsigned long addr; - return gfn_to_hva_memslot_prot(slot, gfn, writable); + addr = gfn_to_hva_memslot_prot(slot, gfn, writable); + if (kvm_is_error_hva(addr)) + return addr; + + if (!kvm_mem_attributes_may_read_gfn(vcpu->kvm, gfn)) + return KVM_HVA_ERR_BAD; + + if (writable && !kvm_mem_attributes_may_write_gfn(vcpu->kvm, gfn)) + *writable = false; + + return addr; } static bool kvm_is_ad_tracked_page(struct page *page) -- 2.52.0