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[35.185.214.157]) by smtp.gmail.com with ESMTPSA id x5-20020a170902b40500b0015e8d4eb29bsm1885958plr.229.2022.05.05.12.14.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 May 2022 12:14:51 -0700 (PDT) Date: Thu, 5 May 2022 19:14:48 +0000 From: Sean Christopherson To: Ben Gardon Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Peter Xu , David Matlack , Jim Mattson , David Dunn , Jing Zhang , Junaid Shahid Subject: Re: [PATCH v7 10/11] KVM: selftests: Test disabling NX hugepages on a VM Message-ID: References: <20220503183045.978509-1-bgardon@google.com> <20220503183045.978509-11-bgardon@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220503183045.978509-11-bgardon@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, May 03, 2022, Ben Gardon wrote: > + if (disable_nx_huge_pages) { > + /* > + * Cannot run the test without NX huge pages if the kernel > + * does not support it. > + */ > + if (!kvm_check_cap(KVM_CAP_VM_DISABLE_NX_HUGE_PAGES)) > + return; > + > + r = __vm_disable_nx_huge_pages(vm); > + if (reboot_permissions) { > + TEST_ASSERT(!r, "Disabling NX huge pages should succeed if process has reboot permissions"); > + } else { > + TEST_ASSERT(r == -EPERM, "This process should not have permission to disable NX huge pages"); This is wrong, the return value on ioctl() failure is -1, the error code is in errno and it's a positive value. LOL, but it passes because EPERM == 1, hilarious. To avoid confusion: TEST_ASSERT(r == -1 && errno == EPERM, "This process should not have permission to disable NX huge pages"); > diff --git a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > index 60bfed8181b9..c21c1f639141 100755 > --- a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > +++ b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > @@ -16,6 +16,8 @@ HUGE_PAGES=$(sudo cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages) > > set +e > > +NXECUTABLE="$(dirname $0)/nx_huge_pages_test" > + > ( > set -e > > @@ -24,7 +26,15 @@ set +e > sudo echo 100 > /sys/module/kvm/parameters/nx_huge_pages_recovery_period_ms > sudo echo 3 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages > > - "$(dirname $0)"/nx_huge_pages_test 887563923 > + # Test with reboot permissions > + sudo setcap cap_sys_boot+ep $NXECUTABLE This leaves cap_sys_boot set on the executable if the script is run as root. Probably this? It's moderately user friendly without going too crazy on error handling. # Test with reboot permissions if [ $(whoami) != "root" ] ; then sudo setcap cap_sys_boot+ep $NXECUTABLE fi $NXECUTABLE 887563923 1 # Test without reboot permissions if [ $(whoami) != "root" ] ; then sudo setcap cap_sys_boot-ep $NXECUTABLE $NXECUTABLE 887563923 0 fi > + $NXECUTABLE 887563923 1 > + > + # Test without reboot permissions > + if [ $(whoami) != "root" ] ; then > + sudo setcap cap_sys_boot-ep $NXECUTABLE > + $NXECUTABLE 887563923 0 I would much prefer a proper flag, not a magic 0 vs. 1. > + fi > ) > RET=$? > > -- > 2.36.0.464.gb9c8b46e94-goog >