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 4BA65C433EF for ; Tue, 22 Feb 2022 14:05:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232680AbiBVOGI (ORCPT ); Tue, 22 Feb 2022 09:06:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232658AbiBVOGF (ORCPT ); Tue, 22 Feb 2022 09:06:05 -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 D5FF715F35F; Tue, 22 Feb 2022 06:05:34 -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 85490B819E2; Tue, 22 Feb 2022 14:05:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC4E7C340F5; Tue, 22 Feb 2022 14:05:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645538732; bh=QSmrNF4OdOSn/paHinDtyUe4KZI0IlZBOC4ndEua4M8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DYtT8C7PouzLYkYxX/KTD320vQlP171GhCQqtYDlw3xj/fHWecUJMgeJ5EGwxRLCU kUfWSaS/CBCQRJ6HbnWZUsGmq6P5kLZZ0w12FcV8IQnXzV3ZT6vvkET9aFMkEmTV4/ mljEDhiGelb3FT37VbMaZgnJZfwHj1430u9MlT6WXeUcXUiapM1fl6X4fY0/YVw9mE 95XrsbZ5f1Rr4GHV9NEAweERFhrZ9ut4TBM8E5zhqY6aFG+SXZ/W1+C8inxHL102Tg GPqyE9F73gOCowAZTi98/aoMIOm7FUmBFYcBQNXkoFiNZQR+hmE4M5c6+Wex34y4Ny hAWDtH5fpgaCw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Maxim Levitsky , Paolo Bonzini , Sasha Levin , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, kvm@vger.kernel.org Subject: [PATCH MANUALSEL 5.15 2/2] KVM: x86: nSVM: deal with L1 hypervisor that intercepts interrupts but lets L2 control them Date: Tue, 22 Feb 2022 09:05:27 -0500 Message-Id: <20220222140527.211584-2-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220222140527.211584-1-sashal@kernel.org> References: <20220222140527.211584-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Maxim Levitsky [ Upstream commit 2b0ecccb55310a4b8ad5d59c703cf8c821be6260 ] Fix a corner case in which the L1 hypervisor intercepts interrupts (INTERCEPT_INTR) and either doesn't set virtual interrupt masking (V_INTR_MASKING) or enters a nested guest with EFLAGS.IF disabled prior to the entry. In this case, despite the fact that L1 intercepts the interrupts, KVM still needs to set up an interrupt window to wait before injecting the INTR vmexit. Currently the KVM instead enters an endless loop of 'req_immediate_exit'. Exactly the same issue also happens for SMIs and NMI. Fix this as well. Note that on VMX, this case is impossible as there is only 'vmexit on external interrupts' execution control which either set, in which case both host and guest's EFLAGS.IF are ignored, or not set, in which case no VMexits are delivered. Signed-off-by: Maxim Levitsky Message-Id: <20220207155447.840194-8-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/svm/svm.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index f05aa7290267d..aeee6df523af9 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3465,11 +3465,13 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu, bool for_injection) if (svm->nested.nested_run_pending) return -EBUSY; + if (svm_nmi_blocked(vcpu)) + return 0; + /* An NMI must not be injected into L2 if it's supposed to VM-Exit. */ if (for_injection && is_guest_mode(vcpu) && nested_exit_on_nmi(svm)) return -EBUSY; - - return !svm_nmi_blocked(vcpu); + return 1; } static bool svm_get_nmi_mask(struct kvm_vcpu *vcpu) @@ -3521,9 +3523,13 @@ bool svm_interrupt_blocked(struct kvm_vcpu *vcpu) static int svm_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection) { struct vcpu_svm *svm = to_svm(vcpu); + if (svm->nested.nested_run_pending) return -EBUSY; + if (svm_interrupt_blocked(vcpu)) + return 0; + /* * An IRQ must not be injected into L2 if it's supposed to VM-Exit, * e.g. if the IRQ arrived asynchronously after checking nested events. @@ -3531,7 +3537,7 @@ static int svm_interrupt_allowed(struct kvm_vcpu *vcpu, bool for_injection) if (for_injection && is_guest_mode(vcpu) && nested_exit_on_intr(svm)) return -EBUSY; - return !svm_interrupt_blocked(vcpu); + return 1; } static void svm_enable_irq_window(struct kvm_vcpu *vcpu) @@ -4286,11 +4292,14 @@ static int svm_smi_allowed(struct kvm_vcpu *vcpu, bool for_injection) if (svm->nested.nested_run_pending) return -EBUSY; + if (svm_smi_blocked(vcpu)) + return 0; + /* An SMI must not be injected into L2 if it's supposed to VM-Exit. */ if (for_injection && is_guest_mode(vcpu) && nested_exit_on_smi(svm)) return -EBUSY; - return !svm_smi_blocked(vcpu); + return 1; } static int svm_enter_smm(struct kvm_vcpu *vcpu, char *smstate) -- 2.34.1