From nobody Sun Sep 7 12:21:38 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DBC9CDB465 for ; Mon, 16 Oct 2023 16:38:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234351AbjJPQil (ORCPT ); Mon, 16 Oct 2023 12:38:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234182AbjJPQgy (ORCPT ); Mon, 16 Oct 2023 12:36:54 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A146E468B; Mon, 16 Oct 2023 09:20:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1697473207; x=1729009207; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=06o7fT7NZNVcS6oNOxRJJ2NUP2CsC3WWbwRpBqTIQ4g=; b=dXUyJ2o5D53alGXMG15YC7qNSp3gtv77RN8svjkElLo9QNvZlRZP9eH4 GTNR65KQ8Ov+r4H6Wutio+nFnreSkHxJMlMqh4ECad/9aRFd0/D0LhhYu BOzDbZ4UBF3GnA3HBDsi2Y/U4yKRv3vM36e6l28RKXA17kWQ4TgmUr0MV wjBI/m6EaRw/Lodtpf5I1H7RYcHLLgzi7uOFbEDvOYqkvKhC+U9Zxp8t6 aGFyJXzqpJdobgAKLRChpUcOWjzhHaicpFiLb50xc3fYb1I4LPlK8Lcfh W3U+oTvahTFzBM08HNUqka60GPf/f6/sWS8vVgMKbdaUVRuku9gJZDEDC A==; X-IronPort-AV: E=McAfee;i="6600,9927,10865"; a="364922005" X-IronPort-AV: E=Sophos;i="6.03,229,1694761200"; d="scan'208";a="364922005" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2023 09:16:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10865"; a="846448270" X-IronPort-AV: E=Sophos;i="6.03,229,1694761200"; d="scan'208";a="846448270" Received: from ls.sc.intel.com (HELO localhost) ([172.25.112.31]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2023 09:16:01 -0700 From: isaku.yamahata@intel.com To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar , David Matlack , Kai Huang , Zhi Wang , chen.bo@intel.com, hang.yuan@intel.com, tina.zhang@intel.com Subject: [PATCH v16 085/116] KVM: TDX: handle ept violation/misconfig exit Date: Mon, 16 Oct 2023 09:14:37 -0700 Message-Id: <7c0c1bf160913eec9ae2f0c5fe32f67d49be34a2.1697471314.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Isaku Yamahata On EPT violation, call a common function, __vmx_handle_ept_violation() to trigger x86 MMU code. On EPT misconfiguration, exit to ring 3 with KVM_EXIT_UNKNOWN. because EPT misconfiguration can't happen as MMIO is trigged by TDG.VP.VMCALL. No point to set a misconfiguration value for the fast path. Signed-off-by: Isaku Yamahata --- v14 -> v15: - use PFERR_GUEST_ENC_MASK to tell the fault is private --- arch/x86/kvm/vmx/common.h | 3 +++ arch/x86/kvm/vmx/tdx.c | 46 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h index 632af7a76d0a..027aa4175d2c 100644 --- a/arch/x86/kvm/vmx/common.h +++ b/arch/x86/kvm/vmx/common.h @@ -87,6 +87,9 @@ static inline int __vmx_handle_ept_violation(struct kvm_v= cpu *vcpu, gpa_t gpa, error_code |=3D (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) !=3D = 0 ? PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK; =20 + if (kvm_is_private_gpa(vcpu->kvm, gpa)) + error_code |=3D PFERR_GUEST_ENC_MASK; + return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0); } =20 diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 618c2ecec26a..f98b27cb9003 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1279,6 +1279,48 @@ void tdx_deliver_interrupt(struct kvm_lapic *apic, i= nt delivery_mode, __vmx_deliver_posted_interrupt(vcpu, &tdx->pi_desc, vector); } =20 +static int tdx_handle_ept_violation(struct kvm_vcpu *vcpu) +{ + unsigned long exit_qual; + + if (kvm_is_private_gpa(vcpu->kvm, tdexit_gpa(vcpu))) { + /* + * Always treat SEPT violations as write faults. Ignore the + * EXIT_QUALIFICATION reported by TDX-SEAM for SEPT violations. + * TD private pages are always RWX in the SEPT tables, + * i.e. they're always mapped writable. Just as importantly, + * treating SEPT violations as write faults is necessary to + * avoid COW allocations, which will cause TDAUGPAGE failures + * due to aliasing a single HPA to multiple GPAs. + */ +#define TDX_SEPT_VIOLATION_EXIT_QUAL EPT_VIOLATION_ACC_WRITE + exit_qual =3D TDX_SEPT_VIOLATION_EXIT_QUAL; + } else { + exit_qual =3D tdexit_exit_qual(vcpu); + if (exit_qual & EPT_VIOLATION_ACC_INSTR) { + pr_warn("kvm: TDX instr fetch to shared GPA =3D 0x%lx @ RIP =3D 0x%lx\n= ", + tdexit_gpa(vcpu), kvm_rip_read(vcpu)); + vcpu->run->exit_reason =3D KVM_EXIT_EXCEPTION; + vcpu->run->ex.exception =3D PF_VECTOR; + vcpu->run->ex.error_code =3D exit_qual; + return 0; + } + } + + trace_kvm_page_fault(vcpu, tdexit_gpa(vcpu), exit_qual); + return __vmx_handle_ept_violation(vcpu, tdexit_gpa(vcpu), exit_qual); +} + +static int tdx_handle_ept_misconfig(struct kvm_vcpu *vcpu) +{ + WARN_ON_ONCE(1); + + vcpu->run->exit_reason =3D KVM_EXIT_UNKNOWN; + vcpu->run->hw.hardware_exit_reason =3D EXIT_REASON_EPT_MISCONFIG; + + return 0; +} + int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath) { union tdx_exit_reason exit_reason =3D to_tdx(vcpu)->exit_reason; @@ -1339,6 +1381,10 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_= t fastpath) WARN_ON_ONCE(fastpath !=3D EXIT_FASTPATH_NONE); =20 switch (exit_reason.basic) { + case EXIT_REASON_EPT_VIOLATION: + return tdx_handle_ept_violation(vcpu); + case EXIT_REASON_EPT_MISCONFIG: + return tdx_handle_ept_misconfig(vcpu); case EXIT_REASON_OTHER_SMI: /* * If reach here, it's not a Machine Check System Management --=20 2.25.1