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 A1D3C446042 for ; Thu, 16 Jul 2026 18:15:16 +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=1784225722; cv=none; b=jEY6e8vJ+Xy2OMlUzi9qFuwM9B7tz3PY7ONYFPWUfw+sn/2UZnL1xZQ5wZOR9GQb/X06hgU3pLrK4RbcK2F9b9KELM3oEOy3EhpiNp1YzgyptFTGGN6tqgtAPiVYqcct8a8En88JdT29qhhdRKOYWAQodbW3SijcekBrLrPM5yE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784225722; c=relaxed/simple; bh=RbB7+rV+Unnkg8P9NDzl3Ie4WCg1IS/jJMOdDDxS3Gg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MUbnOw4aYA09SHeymvazZWoBjrAXQoC9FyUa+GCB7HEFPl6KAUA0YHGc+BUDUtObof/JpU5mUIhUZLRAQmLzs4b8Lw1GvKt7/20F22YKRd0bitBF8/dRTZ2mmeag2wX3P6LE5yUvwmW5JXF7PLBa+NnTV/003K+oWq1zVGIeZv0= 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=is+PyTG3; 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="is+PyTG3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784225712; 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=Tw1WPOSN+5h2YK/GVlX7f0rfZxbYC8aN2XeVHPaNYxU=; b=is+PyTG3OzkBnsxacjXT6pxUhxYIqNKAuCOs0Z0Blq8v9CGBcXl5wvOzBnghhFelrDb4O8 8r5yF2+/BzS4X7p1aucHefnDziha3/NFGfNL8+0Em8gsSAZBvP4HblwdXgwcM3ZpfDBYub VdO+dOcOejT2/8+qunrSPXhkElEFBqQ= 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-584-Z8Gc3n8-M_iYNGzGbcFgEg-1; Thu, 16 Jul 2026 14:15:06 -0400 X-MC-Unique: Z8Gc3n8-M_iYNGzGbcFgEg-1 X-Mimecast-MFC-AGG-ID: Z8Gc3n8-M_iYNGzGbcFgEg_1784225704 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 B64181800672; Thu, 16 Jul 2026 18:15:04 +0000 (UTC) Received: from virtlab1023.lab.eng.rdu2.redhat.lab.eng.rdu2.redhat.com (virtlab1023.lab.eng.rdu2.redhat.com [10.8.1.187]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 481AB1800480; Thu, 16 Jul 2026 18:15:04 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: nsaenz@amazon.com Subject: [PATCH 10/24] KVM: Include memory protections in result of gfn->hva conversion Date: Thu, 16 Jul 2026 14:14:42 -0400 Message-ID: <20260716181456.402786-11-pbonzini@redhat.com> In-Reply-To: <20260716181456.402786-1-pbonzini@redhat.com> References: <20260716181456.402786-1-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 10.30.177.93 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 2dd1b65799e4..f10ab70b99dc 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2593,8 +2593,26 @@ 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 a47b62c2c9ce..56016aab0aad 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2764,13 +2764,38 @@ 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); @@ -2796,15 +2821,37 @@ 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 (!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 (!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