From patchwork Tue Jul 27 21:09:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 487483 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19EDCC00143 for ; Tue, 27 Jul 2021 21:10:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F1C2560F94 for ; Tue, 27 Jul 2021 21:10:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232844AbhG0VKD (ORCPT ); Tue, 27 Jul 2021 17:10:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:54670 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235239AbhG0VJV (ORCPT ); Tue, 27 Jul 2021 17:09:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627420160; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=epqNANSa//JBOqbfDJlxqgrU5mQ/ZOYCzCBkRvtlhEQ=; b=IeZyyoKjFAkH66rOLSKxrOdbLez6lR60UdcfzlYW2cWTF+gJfnWOpSrsMZX9/ECYdfX5MT fpPvA9QLOJJDYvomNvopwjh6XVvJe6dY/yU/hT2FxFOwairdoficJhUuxayq7Nz80GZxGa vqFDxaenCtleJRlafYpffna1KgAzLww= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-468-IR3A2OY7PgWndQt2uHqkyQ-1; Tue, 27 Jul 2021 17:09:18 -0400 X-MC-Unique: IR3A2OY7PgWndQt2uHqkyQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9D52C8010F4; Tue, 27 Jul 2021 21:09:17 +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 27AE460C9F; Tue, 27 Jul 2021 21:09:17 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, stable@vger.kernel.org, Stas Sergeev Subject: [PATCH v3] KVM: x86: accept userspace interrupt only if no event is injected Date: Tue, 27 Jul 2021 17:09:16 -0400 Message-Id: <20210727210916.1652841-1-pbonzini@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Once an exception has been injected, any side effects related to the exception (such as setting CR2 or DR6) have been taked place. Therefore, once KVM sets the VM-entry interruption information field or the AMD EVENTINJ field, the next VM-entry must deliver that exception. Pending interrupts are processed after injected exceptions, so in theory it would not be a problem to use KVM_INTERRUPT when an injected exception is present. However, DOSEMU is using run->ready_for_interrupt_injection to detect interrupt windows and then using KVM_SET_SREGS/KVM_SET_REGS to inject the interrupt manually. For this to work, the interrupt window must be delayed after the completion of the previous event injection. Cc: stable@vger.kernel.org Reported-by: Stas Sergeev Tested-by: Stas Sergeev Fixes: 71cc849b7093 ("KVM: x86: Fix split-irqchip vs interrupt injection window request") Signed-off-by: Paolo Bonzini Reviewed-by: Sean Christopherson Acked-by: stsp2@yandex.ru --- arch/x86/kvm/x86.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4116567f3d44..e5d5c5ed7dd4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4358,8 +4358,17 @@ static int kvm_cpu_accept_dm_intr(struct kvm_vcpu *vcpu) static int kvm_vcpu_ready_for_interrupt_injection(struct kvm_vcpu *vcpu) { - return kvm_arch_interrupt_allowed(vcpu) && - kvm_cpu_accept_dm_intr(vcpu); + /* + * Do not cause an interrupt window exit if an exception + * is pending or an event needs reinjection; userspace + * might want to inject the interrupt manually using KVM_SET_REGS + * or KVM_SET_SREGS. For that to work, we must be at an + * instruction boundary and with no events half-injected. + */ + return (kvm_arch_interrupt_allowed(vcpu) && + kvm_cpu_accept_dm_intr(vcpu) && + !kvm_event_needs_reinjection(vcpu) && + !vcpu->arch.exception.pending); } static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,