From mboxrd@z Thu Jan 1 00:00:00 1970 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 0612AC433EF for ; Sun, 5 Dec 2021 12:36:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233683AbhLEMji (ORCPT ); Sun, 5 Dec 2021 07:39:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229852AbhLEMji (ORCPT ); Sun, 5 Dec 2021 07:39:38 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8AD3C061714 for ; Sun, 5 Dec 2021 04:36:10 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 72C05B80E28 for ; Sun, 5 Dec 2021 12:36:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9501AC341C1; Sun, 5 Dec 2021 12:36:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638707768; bh=TJMSwFoMHKiWEfF0yDv3kakasohfjQH9MHHIvM4UJdA=; h=Subject:To:Cc:From:Date:From; b=Z4QME1lYLX9qyw/RptTpjCOjzanU/oKYznyuk45kMh/jqI5GPgQcSoPq69OlW+XID N1KGFo0TbK68zYLiBTkfxRzRsnsMbrk3tf+87y3eEr7cISGIcIw6cIKbTo3Zx2qHCa u827DQ6gXHHXuj1SGUjk2BXtvYS7+E/8pOf/xKbc= Subject: FAILED: patch "[PATCH] KVM: nVMX: Emulate guest TLB flush on nested VM-Enter with" failed to apply to 4.14-stable tree To: seanjc@google.com, jiangshanlai+lkml@gmail.com, pbonzini@redhat.com Cc: From: Date: Sun, 05 Dec 2021 13:36:00 +0100 Message-ID: <1638707760196110@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 712494de96f35f3e146b36b752c2afe0fdc0f0cc Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 25 Nov 2021 01:49:44 +0000 Subject: [PATCH] KVM: nVMX: Emulate guest TLB flush on nested VM-Enter with new vpid12 Fully emulate a guest TLB flush on nested VM-Enter which changes vpid12, i.e. L2's VPID, instead of simply doing INVVPID to flush real hardware's TLB entries for vpid02. From L1's perspective, changing L2's VPID is effectively a TLB flush unless "hardware" has previously cached entries for the new vpid12. Because KVM tracks only a single vpid12, KVM doesn't know if the new vpid12 has been used in the past and so must treat it as a brand new, never been used VPID, i.e. must assume that the new vpid12 represents a TLB flush from L1's perspective. For example, if L1 and L2 share a CR3, the first VM-Enter to L2 (with a VPID) is effectively a TLB flush as hardware/KVM has never seen vpid12 and thus can't have cached entries in the TLB for vpid12. Reported-by: Lai Jiangshan Fixes: 5c614b3583e7 ("KVM: nVMX: nested VPID emulation") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20211125014944.536398-3-seanjc@google.com> Signed-off-by: Paolo Bonzini diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 8e55aaef33ee..64f2828035c2 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1162,29 +1162,26 @@ static void nested_vmx_transition_tlb_flush(struct kvm_vcpu *vcpu, WARN_ON(!enable_vpid); /* - * If VPID is enabled and used by vmc12, but L2 does not have a unique - * TLB tag (ASID), i.e. EPT is disabled and KVM was unable to allocate - * a VPID for L2, flush the current context as the effective ASID is - * common to both L1 and L2. - * - * Defer the flush so that it runs after vmcs02.EPTP has been set by - * KVM_REQ_LOAD_MMU_PGD (if nested EPT is enabled) and to avoid - * redundant flushes further down the nested pipeline. - * - * If a TLB flush isn't required due to any of the above, and vpid12 is - * changing then the new "virtual" VPID (vpid12) will reuse the same - * "real" VPID (vpid02), and so needs to be flushed. There's no direct - * mapping between vpid02 and vpid12, vpid02 is per-vCPU and reused for - * all nested vCPUs. Remember, a flush on VM-Enter does not invalidate - * guest-physical mappings, so there is no need to sync the nEPT MMU. + * VPID is enabled and in use by vmcs12. If vpid12 is changing, then + * emulate a guest TLB flush as KVM does not track vpid12 history nor + * is the VPID incorporated into the MMU context. I.e. KVM must assume + * that the new vpid12 has never been used and thus represents a new + * guest ASID that cannot have entries in the TLB. */ - if (!nested_has_guest_tlb_tag(vcpu)) { - kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu); - } else if (is_vmenter && - vmcs12->virtual_processor_id != vmx->nested.last_vpid) { + if (is_vmenter && vmcs12->virtual_processor_id != vmx->nested.last_vpid) { vmx->nested.last_vpid = vmcs12->virtual_processor_id; - vpid_sync_context(nested_get_vpid02(vcpu)); + kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu); + return; } + + /* + * If VPID is enabled, used by vmc12, and vpid12 is not changing but + * does not have a unique TLB tag (ASID), i.e. EPT is disabled and + * KVM was unable to allocate a VPID for L2, flush the current context + * as the effective ASID is common to both L1 and L2. + */ + if (!nested_has_guest_tlb_tag(vcpu)) + kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu); } static bool is_bitwise_subset(u64 superset, u64 subset, u64 mask)