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 2BE4DC71130 for ; Thu, 17 Aug 2023 23:35:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356103AbjHQXeq (ORCPT ); Thu, 17 Aug 2023 19:34:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356093AbjHQXej (ORCPT ); Thu, 17 Aug 2023 19:34:39 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F56130D6 for ; Thu, 17 Aug 2023 16:34:38 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-565aba2e397so523971a12.3 for ; Thu, 17 Aug 2023 16:34:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1692315278; x=1692920078; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=YpFMVDLsowSmpGWrptrxFQAXS4ajKEvJ2WJs4xhDDoI=; b=YhhQT8Lv8ANNNhYui/aJrAkfGeBj2c/dOfAdg2WRXptW2ITBe5CyUtscAkjyj2fxc4 7bNfYQ8NEIH/nUt83jDhbSYtDgCVvw9zMSNVaPwUXjJsD0r4pF4Lk0wMB0XgABSejUh0 4n0bFDToRA6Dz1vKaq6xm/ZKkznSnA5I597y4MUymv8nAlYP0eWunOfKpGrpXYTCHSiD QYE6m3jofRj++In4Kai4b0FqvGnItsyjlac6xBZo1d/JWba4ZWfCdn9EThyQH7MAjmnb jIc2ILIA3EDtcIK/n56lRDj0yO7N3tnwPgeJDcofjjg/A8vmTALZFXVz3YV/8QGR8m1B WHmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692315278; x=1692920078; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=YpFMVDLsowSmpGWrptrxFQAXS4ajKEvJ2WJs4xhDDoI=; b=RwnzQ5cslW8ExFRjcRH/mkjOi7gHctllsuzatAvQI1iuHQrXkrMhVE6uKmo4mq3ky8 xaLIX0u7w2Y04FX9TZHXAib0WG6XNb40mHQpIChAeXUvRFMb7cgy3Tg55EaSaYgVKXFV Fx9wcPSM59oSLI0eEh9MG/oVup67gwQPmKeHfzZstHOJnXhylQV6FgcMry8RWUDlXY/u T2dIQdvvxDr2hck3B78QYUpxGxbDQRD602S+I5lTd6FafSLi6VbOYHt1znFCMx3mU9lC 727wLjRzJPkpoPEkAEsNHuY6YmopIvs4nwAFc4LOZh+0gg5W/lt1PqochGncXlOumexW 2u6w== X-Gm-Message-State: AOJu0YwPMks4FM4Sf+Cv+tAVtrinSmaC7Ck+B/iNhf+IuuteWJmkMtrl bamTaUfZcFgW7AelWUqOSoPXXTQzVgc= X-Google-Smtp-Source: AGHT+IEa+4IbiOaMkbL+znRevOCe3T15GMNjBwaL4EWX4Nf/t8zYxIVwGhKwNoi2vZANROkAJu/VIv8ow3s= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a63:715b:0:b0:567:c791:ce64 with SMTP id b27-20020a63715b000000b00567c791ce64mr122102pgn.8.1692315277840; Thu, 17 Aug 2023 16:34:37 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 17 Aug 2023 16:34:30 -0700 In-Reply-To: <20230817233430.1416463-1-seanjc@google.com> Mime-Version: 1.0 References: <20230817233430.1416463-1-seanjc@google.com> X-Mailer: git-send-email 2.42.0.rc1.204.g551eb34607-goog Message-ID: <20230817233430.1416463-3-seanjc@google.com> Subject: [PATCH 2/2] KVM: selftests: Explicit set #UD when *potentially* injecting exception From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Explicitly set the exception vector to #UD when potentially injecting an exception in sync_regs_test's subtests that try to detect TOCTOU bugs in KVM's handling of exceptions injected by userspace. A side effect of the original KVM bug was that KVM would clear the vector, but relying on KVM to clear the vector (i.e. make it #DE) makes it less likely that the test would ever find *new* KVM bugs, e.g. because only the first iteration would run with a legal vector to start. Explicitly inject #UD for race_events_inj_pen() as well, e.g. so that it doesn't inherit the illegal 255 vector from race_events_exc(), which currently runs first. Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/x86_64/sync_regs_test.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c index 21e99dae2ff2..00965ba33f73 100644 --- a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c +++ b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c @@ -91,6 +91,8 @@ static void *race_events_inj_pen(void *arg) struct kvm_run *run = (struct kvm_run *)arg; struct kvm_vcpu_events *events = &run->s.regs.events; + WRITE_ONCE(events->exception.nr, UD_VECTOR); + for (;;) { WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS); WRITE_ONCE(events->flags, 0); @@ -115,6 +117,7 @@ static void *race_events_exc(void *arg) for (;;) { WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_EVENTS); WRITE_ONCE(events->flags, 0); + WRITE_ONCE(events->exception.nr, UD_VECTOR); WRITE_ONCE(events->exception.pending, 1); WRITE_ONCE(events->exception.nr, 255); -- 2.42.0.rc1.204.g551eb34607-goog