From patchwork Tue Feb 27 23:20:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13574564 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 74F3F5645C for ; Tue, 27 Feb 2024 23:21:06 +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=1709076069; cv=none; b=VKoI5ZkWv4YW3m8wnQGgRU1ea606RB4RexJrv94xtU5sewWeRTYuMCiAmdix/uoovDLLetnrqsPATEManKR44lnZWV7k887jf/MklTarugM8aGsQwl7c8IAPNfoOBGmRKcAivoDBcAV+nbef5wHTbv9fGtnD80QrnL6BhJ9zv1A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709076069; c=relaxed/simple; bh=xRmVOKW+U3cJ5RX888tGYOi8yF1+QheQSC7TRhNS304=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=XD/82y1NV65sdthZLmYAQskPneLznPMl4NrbQHBgry6dGM8DkLAbQZfoLpYEgtwWwF7gLbaajd4jk2NNJw5WLtGcL5lDimO2preRodE+lkT1ZWxi4WHObj60f/pEP26iP7Bqhe1JY0Uo76acuxy1Y0k12sy55JztUGvk+Q3GzP4= 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=ZuVlIIwR; 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="ZuVlIIwR" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709076065; 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=18Rzjsoz7zhdGFf0HyQTJYlfCD2y/TVy5xqJ/ZcFN24=; b=ZuVlIIwRpIR9osJKy0SyB6DtOGQ8yLzJNeLcnmDAuizwQ0kbr2Nxm0tTizXs/J61NsjXm2 NktVKdQlMk99FqMIvPFQVDCr/g2zWUTuMh18xnByZ2g+TFU40Fw80YsctV+9mGOljCY4kR TMa+lJ/fYjjFPmle6TJuzC1ziDDqbtQ= 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-668-XfzX3fwxMkWqYPPw3M1Kgw-1; Tue, 27 Feb 2024 18:21:02 -0500 X-MC-Unique: XfzX3fwxMkWqYPPw3M1Kgw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (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 CF7803869142; Tue, 27 Feb 2024 23:21:01 +0000 (UTC) Received: from virtlab511.virt.lab.eng.bos.redhat.com (virtlab511.virt.lab.eng.bos.redhat.com [10.19.152.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8A4C942283; Tue, 27 Feb 2024 23:21:01 +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, thomas.lendacky@amd.com, Binbin Wu Subject: [PATCH 04/21] KVM: x86/mmu: Allow non-zero value for non-present SPTE and removed SPTE Date: Tue, 27 Feb 2024 18:20:43 -0500 Message-Id: <20240227232100.478238-5-pbonzini@redhat.com> In-Reply-To: <20240227232100.478238-1-pbonzini@redhat.com> References: <20240227232100.478238-1-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 10.11.54.5 From: Sean Christopherson For TD guest, the current way to emulate MMIO doesn't work any more, as KVM is not able to access the private memory of TD guest and do the emulation. Instead, TD guest expects to receive #VE when it accesses the MMIO and then it can explicitly make hypercall to KVM to get the expected information. To achieve this, the TDX module always enables "EPT-violation #VE" in the VMCS control. And accordingly, for the MMIO spte for the shared GPA, 1. KVM needs to set "suppress #VE" bit for the non-present SPTE so that EPT violation happens on TD accessing MMIO range. 2. On EPT violation, KVM sets the MMIO spte to clear "suppress #VE" bit so the TD guest can receive the #VE instead of EPT misconfiguration unlike VMX case. For the shared GPA that is not populated yet, EPT violation need to be triggered when TD guest accesses such shared GPA. The non-present SPTE value for shared GPA should set "suppress #VE" bit. Add "suppress #VE" bit (bit 63) to SHADOW_NONPRESENT_VALUE and REMOVED_SPTE. Unconditionally set the "suppress #VE" bit (which is bit 63) for both AMD and Intel as: 1) AMD hardware doesn't use this bit when present bit is off; 2) for normal VMX guest, KVM never enables the "EPT-violation #VE" in VMCS control and "suppress #VE" bit is ignored by hardware. Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata Reviewed-by: Binbin Wu Message-Id: Signed-off-by: Paolo Bonzini Reviewed-by: Xu Yilun Reviewed-by: Xiaoyao Li --- arch/x86/kvm/mmu/spte.h | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 4d1799ba2bf8..26bc95bbc962 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -149,7 +149,20 @@ 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) +/* + * Non-present SPTE value for both VMX and SVM for TDP MMU. + * For SVM NPT, for non-present spte (bit 0 = 0), other bits are ignored. + * For VMX EPT, bit 63 is ignored if #VE is disabled. (EPT_VIOLATION_VE=0) + * bit 63 is #VE suppress if #VE is enabled. (EPT_VIOLATION_VE=1) + * For TDX: + * TDX module sets EPT_VIOLATION_VE for Secure-EPT and conventional EPT + */ +#ifdef CONFIG_X86_64 +#define SHADOW_NONPRESENT_VALUE BIT_ULL(63) +static_assert(!(SHADOW_NONPRESENT_VALUE & SPTE_MMU_PRESENT_MASK)); +#else #define SHADOW_NONPRESENT_VALUE 0ULL +#endif extern u64 __read_mostly shadow_host_writable_mask; extern u64 __read_mostly shadow_mmu_writable_mask; @@ -196,7 +209,7 @@ 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));