From patchwork Thu Apr 4 18:50:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13618137 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 10BD8131BB9 for ; Thu, 4 Apr 2024 18:50:39 +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=1712256641; cv=none; b=WU3QZT1Y2hTw5MBtU5XmG8VaPD/ltydDQ+0sKu9f2Rxua1ex3gZYCvIGeQc7lz+uPs1YaK6VsjherlEN4iaFxXKETqj+NaOqV8r2Sm57dvTiuMRZLqj4+yxZHhjteq0F5EXBB4q0tTrNY2b9grGRrf0OkdXqtAoYcijX7f/Y7ko= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712256641; c=relaxed/simple; bh=JhCLT6R3dEV4Z8kPXKqhhzXcGFUKttw3pZHa+JT0OpU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=W1LP3VJfTvpoZ6/L17bMmHvnouIDLnls1IfVrWX6qUT+H98DQ2+4of8nki+MwNPYDH6jQmn9DrgRbXpi7NeEOjostm9I5R+ici9g4YpAksiqGLQjo0w1q4mxzgygxXH7VJsb17IaPJEFEWGk0Ce7yl5OiVF7n9jfK+YCreBibdE= 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=XN6XcKmF; arc=none smtp.client-ip=170.10.133.124 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="XN6XcKmF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712256639; 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=Nc3SKOOYPHg3uIsI8oCYk9QWrQ5YHEK98RfXdPCT6Bs=; b=XN6XcKmFkE97tmm1QFxW0IIIuub5EE4loURy+AO7p+kG/GkY3UVRsmkXcPhHp4APaT1rzO gldh4UEbqW47if+droSgyLUKRIQQvuET9apa7VsGbahOWfzcvM4IOxGoAWF018mHWCBUe/ UvyAA6xB4QOPlTjY3Yb16xcFto9CiNo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-58-9DwWGaL3OZ2V6bZuCBaOTQ-1; Thu, 04 Apr 2024 14:50:37 -0400 X-MC-Unique: 9DwWGaL3OZ2V6bZuCBaOTQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 157CE85A5B7; Thu, 4 Apr 2024 18:50:37 +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 E2B8D2024517; Thu, 4 Apr 2024 18:50:36 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, michael.roth@amd.com, isaku.yamahata@intel.com Subject: [PATCH 11/11] KVM: x86: Add gmem hook for determining max NPT mapping level Date: Thu, 4 Apr 2024 14:50:33 -0400 Message-ID: <20240404185034.3184582-12-pbonzini@redhat.com> In-Reply-To: <20240404185034.3184582-1-pbonzini@redhat.com> References: <20240404185034.3184582-1-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 10.11.54.4 From: Michael Roth In the case of SEV-SNP, whether or not a 2MB page can be mapped via a 2MB mapping in the guest's nested page table depends on whether or not any subpages within the range have already been initialized as private in the RMP table. The existing mixed-attribute tracking in KVM is insufficient here, for instance: - gmem allocates 2MB page - guest issues PVALIDATE on 2MB page - guest later converts a subpage to shared - SNP host code issues PSMASH to split 2MB RMP mapping to 4K - KVM MMU splits NPT mapping to 4K At this point there are no mixed attributes, and KVM would normally allow for 2MB NPT mappings again, but this is actually not allowed because the RMP table mappings are 4K and cannot be promoted on the hypervisor side, so the NPT mappings must still be limited to 4K to match this. Add a hook to determine the max NPT mapping size in situations like this. Signed-off-by: Michael Roth Message-Id: <20231230172351.574091-31-michael.roth@amd.com> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/mmu/mmu.c | 8 ++++++++ 3 files changed, 11 insertions(+) diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index c81990937ab4..2db87a6fd52a 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -140,6 +140,7 @@ KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); KVM_X86_OP_OPTIONAL(get_untagged_addr) KVM_X86_OP_OPTIONAL(alloc_apic_backing_page) KVM_X86_OP_OPTIONAL_RET0(gmem_prepare) +KVM_X86_OP_OPTIONAL_RET0(gmem_validate_fault) KVM_X86_OP_OPTIONAL(gmem_invalidate) #undef KVM_X86_OP diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 59c7b95034fc..67dc108dd366 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1811,6 +1811,8 @@ struct kvm_x86_ops { void *(*alloc_apic_backing_page)(struct kvm_vcpu *vcpu); int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order); void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end); + int (*gmem_validate_fault)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, bool is_private, + u8 *max_level); }; struct kvm_x86_nested_ops { diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 992e651540e8..13dd367b8af1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4338,6 +4338,14 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu, fault->max_level); fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); + r = static_call(kvm_x86_gmem_validate_fault)(vcpu->kvm, fault->pfn, + fault->gfn, fault->is_private, + &fault->max_level); + if (r) { + kvm_release_pfn_clean(fault->pfn); + return r; + } + return RET_PF_CONTINUE; }