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AJvYcCV7e/pPZjoszqArpkdvJ7oT+Uj+INQ6/JICeQKBPjjYK1mnk3tBmdKCpu/3vZWeGAVl6DDVqoyB1DSAhSrV@vger.kernel.org X-Gm-Message-State: AOJu0YwFQU30R7F5dHQi4wp2S5JucJRUmeAv6GFdJKP9BzNURRmInXGQ eYCL+CpfiO8F5g6kFYlTWKHRm3/RFfMfGJHCsOVOHoYYFDomW9+7wJKbepI5pLahudvczRV6V36 0HFji9/47cnVzWdGIULxd/vuijQ== X-Google-Smtp-Source: AGHT+IFZZue4eVCNyGlBlVu3FOMYDdiN/+lNxD2W2guGukj7N1aj09nrbw9YDmV/sDzoeyH8oFlR4vBN8C7KtAQknw== X-Received: from pjyp15.prod.google.com ([2002:a17:90a:e70f:b0:2ef:d283:5089]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4b0f:b0:2fe:b907:562f with SMTP id 98e67ed59e1d1-30e7d527e41mr6797759a91.14.1747417369222; Fri, 16 May 2025 10:42:49 -0700 (PDT) Date: Fri, 16 May 2025 10:42:47 -0700 In-Reply-To: <6825f0f3ac8a7_337c392942d@iweiny-mobl.notmuch> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <65afac3b13851c442c72652904db6d5755299615.1747264138.git.ackerleytng@google.com> <6825f0f3ac8a7_337c392942d@iweiny-mobl.notmuch> Message-ID: Subject: Re: [RFC PATCH v2 03/51] KVM: selftests: Update guest_memfd_test for INIT_PRIVATE flag From: Ackerley Tng To: Ira Weiny , kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-fsdevel@vger.kernel.org Cc: aik@amd.com, ajones@ventanamicro.com, akpm@linux-foundation.org, amoorthy@google.com, anthony.yznaga@oracle.com, anup@brainfault.org, aou@eecs.berkeley.edu, bfoster@redhat.com, binbin.wu@linux.intel.com, brauner@kernel.org, catalin.marinas@arm.com, chao.p.peng@intel.com, chenhuacai@kernel.org, dave.hansen@intel.com, david@redhat.com, dmatlack@google.com, dwmw@amazon.co.uk, erdemaktas@google.com, fan.du@intel.com, fvdl@google.com, graf@amazon.com, haibo1.xu@intel.com, hch@infradead.org, hughd@google.com, ira.weiny@intel.com, isaku.yamahata@intel.com, jack@suse.cz, james.morse@arm.com, jarkko@kernel.org, jgg@ziepe.ca, jgowans@amazon.com, jhubbard@nvidia.com, jroedel@suse.de, jthoughton@google.com, jun.miao@intel.com, kai.huang@intel.com, keirf@google.com, kent.overstreet@linux.dev, kirill.shutemov@intel.com, liam.merwick@oracle.com, maciej.wieczor-retman@intel.com, mail@maciej.szmigiero.name, maz@kernel.org, mic@digikod.net, michael.roth@amd.com, mpe@ellerman.id.au, muchun.song@linux.dev, nikunj@amd.com, nsaenz@amazon.es, oliver.upton@linux.dev, palmer@dabbelt.com, pankaj.gupta@amd.com, paul.walmsley@sifive.com, pbonzini@redhat.com, pdurrant@amazon.co.uk, peterx@redhat.com, pgonda@google.com, pvorel@suse.cz, qperret@google.com, quic_cvanscha@quicinc.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, quic_svaddagi@quicinc.com, quic_tsoni@quicinc.com, richard.weiyang@gmail.com, rick.p.edgecombe@intel.com, rientjes@google.com, roypat@amazon.co.uk, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, steven.sistare@oracle.com, suzuki.poulose@arm.com, tabba@google.com, thomas.lendacky@amd.com, usama.arif@bytedance.com, vannapurve@google.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, vkuznets@redhat.com, wei.w.wang@intel.com, will@kernel.org, willy@infradead.org, xiaoyao.li@intel.com, yan.y.zhao@intel.com, yilun.xu@intel.com, yuzenghui@huawei.com, zhiquan1.li@intel.com Content-Type: text/plain; charset="UTF-8" Ira Weiny writes: > Ackerley Tng wrote: >> Test that GUEST_MEMFD_FLAG_INIT_PRIVATE is only valid when >> GUEST_MEMFD_FLAG_SUPPORT_SHARED is set. >> >> Change-Id: I506e236a232047cfaee17bcaed02ee14c8d25bbb >> Signed-off-by: Ackerley Tng >> --- >> .../testing/selftests/kvm/guest_memfd_test.c | 36 ++++++++++++------- >> 1 file changed, 24 insertions(+), 12 deletions(-) >> >> diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c >> index 60aaba5808a5..bf2876cbd711 100644 >> --- a/tools/testing/selftests/kvm/guest_memfd_test.c >> +++ b/tools/testing/selftests/kvm/guest_memfd_test.c >> @@ -401,13 +401,31 @@ static void test_with_type(unsigned long vm_type, uint64_t guest_memfd_flags, >> kvm_vm_release(vm); >> } >> >> +static void test_vm_with_gmem_flag(struct kvm_vm *vm, uint64_t flag, >> + bool expect_valid) >> +{ >> + size_t page_size = getpagesize(); >> + int fd; >> + >> + fd = __vm_create_guest_memfd(vm, page_size, flag); >> + >> + if (expect_valid) { >> + TEST_ASSERT(fd > 0, >> + "guest_memfd() with flag '0x%lx' should be valid", >> + flag); >> + close(fd); >> + } else { >> + TEST_ASSERT(fd == -1 && errno == EINVAL, >> + "guest_memfd() with flag '0x%lx' should fail with EINVAL", >> + flag); >> + } >> +} >> + >> static void test_vm_type_gmem_flag_validity(unsigned long vm_type, >> uint64_t expected_valid_flags) >> { >> - size_t page_size = getpagesize(); >> struct kvm_vm *vm; >> uint64_t flag = 0; >> - int fd; >> >> if (!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) >> return; >> @@ -415,17 +433,11 @@ static void test_vm_type_gmem_flag_validity(unsigned long vm_type, >> vm = vm_create_barebones_type(vm_type); >> >> for (flag = BIT(0); flag; flag <<= 1) { >> - fd = __vm_create_guest_memfd(vm, page_size, flag); >> + test_vm_with_gmem_flag(vm, flag, flag & expected_valid_flags); >> >> - if (flag & expected_valid_flags) { >> - TEST_ASSERT(fd > 0, >> - "guest_memfd() with flag '0x%lx' should be valid", >> - flag); >> - close(fd); >> - } else { >> - TEST_ASSERT(fd == -1 && errno == EINVAL, >> - "guest_memfd() with flag '0x%lx' should fail with EINVAL", >> - flag); >> + if (flag == GUEST_MEMFD_FLAG_SUPPORT_SHARED) { >> + test_vm_with_gmem_flag( >> + vm, flag | GUEST_MEMFD_FLAG_INIT_PRIVATE, true); > > I don't understand the point of this check. In 2/51 we set > GUEST_MEMFD_FLAG_INIT_PRIVATE when GUEST_MEMFD_FLAG_SUPPORT_SHARED is set. > > When can this check ever fail? > > Ira In 02/51, GUEST_MEMFD_FLAG_INIT_PRIVATE is not set by default, GUEST_MEMFD_FLAG_INIT_PRIVATE is set as one of the valid_flags. The intention is that GUEST_MEMFD_FLAG_INIT_PRIVATE is only valid if GUEST_MEMFD_FLAG_SUPPORT_SHARED is requested by userspace. In this test, the earlier part before the if block calls test_vm_with_gmem_flag() all valid flags, and that already tests GUEST_MEMFD_FLAG_SUPPORT_SHARED individually. Specifically if GUEST_MEMFD_FLAG_SUPPORT_SHARED is set, this if block adds a test for when both GUEST_MEMFD_FLAG_SUPPORT_SHARED and GUEST_MEMFD_FLAG_INIT_PRIVATE are set, and sets that expect_valid is true. This second test doesn't fail, it is meant to check that the kernel allows the pair of flags to be set. Hope that makes sense.