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AJvYcCWAQ/zVjo+YE2O7+9tTlSX6sfqt27ZCE35Gs14SrrKdoMwh3Vtpk1CFijccuoOQYEhOP9FYShR9Rht8AeA=@vger.kernel.org X-Gm-Message-State: AOJu0Yx6Tt5wULJwvw7RrppEP7RNckbeUe751UppKzpBx5i/W7sJhBGm zGbtO0TDmjLw9q25umY3HtnpOLkwOdk2eEg4LlIE/58hjOFZYOvotHJfwInsckcY8NowkILsiwb GMkUZKQ== X-Google-Smtp-Source: AGHT+IH/6fHMrWMV8yp+8Ppnbbm83SfdopptQSAUB91QvYTFNTxXFVFSpf5U8i3i7fNPRxzlbwQGpMJ/fbA= X-Received: from pfbei17.prod.google.com ([2002:a05:6a00:80d1:b0:772:3537:d602]) (user=wyihan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:1593:b0:2f3:3e1b:de66 with SMTP id adf61e73a8af0-33495d4ea9cmr1351247637.7.1760553426186; Wed, 15 Oct 2025 11:37:06 -0700 (PDT) Date: Wed, 15 Oct 2025 18:35:54 +0000 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.51.0.788.g6d19910ace-goog Message-ID: <0ec7349858142439ed0a250e6c04edf84cb0f488.1760551864.git.wyihan@google.com> Subject: [RFC PATCH 3/3] KVM: selftests: Test guest_memfd behavior with respect to stage 2 page tables From: Lisa Wang To: linmiaohe@huawei.com, nao.horiguchi@gmail.com, akpm@linux-foundation.org, pbonzini@redhat.com, shuah@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.or, linux-kselftest@vger.kernel.org Cc: david@redhat.com, rientjes@google.com, seanjc@google.com, ackerleytng@google.com, vannapurve@google.com, michael.roth@amd.com, jiaqiyan@google.com, tabba@google.com, dave.hansen@linux.intel.com, Lisa Wang Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Test that + memory failure handling results in unmapping of bad memory from stage 2 page tables, hence requiring faulting on next guest access + when the guest tries to fault a poisoned page from guest_memfd, the userspace VMM informed with EHWPOISON Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Signed-off-by: Lisa Wang --- .../testing/selftests/kvm/guest_memfd_test.c | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing= /selftests/kvm/guest_memfd_test.c index 7bcf8d2d5d4d..dc3398e22edd 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -539,6 +539,70 @@ static void test_guest_memfd_guest(void) kvm_vm_free(vm); } =20 +static void __guest_code_read(uint8_t *mem) +{ + READ_ONCE(*mem); + GUEST_DONE(); +} + +static void guest_read(struct kvm_vcpu *vcpu, uint64_t gpa, int expected_e= rrno) +{ + vcpu_arch_set_entry_point(vcpu, __guest_code_read); + vcpu_args_set(vcpu, 1, gpa); + + if (expected_errno) { + TEST_ASSERT_EQ(_vcpu_run(vcpu), -1); + TEST_ASSERT_EQ(errno, expected_errno); + } else { + vcpu_run(vcpu); + TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE); + } +} + +static void test_memory_failure_guest(void) +{ + const uint64_t gpa =3D SZ_4G; + const int slot =3D 1; + + unsigned long memory_failure_pfn; + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + uint8_t *mem; + size_t size; + int fd; + + if (!kvm_has_cap(KVM_CAP_GUEST_MEMFD_FLAGS)) + return; + + vm =3D __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, __gues= t_code_read); + + size =3D vm->page_size; + fd =3D vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP | GUEST_MEMF= D_FLAG_INIT_SHARED); + vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL= , fd, 0); + + mem =3D mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem !=3D MAP_FAILED, "mmap() for guest_memfd should succeed."= ); + virt_pg_map(vm, gpa, gpa); + + /* Fault in page to read pfn, then unmap page for testing. */ + READ_ONCE(*mem); + memory_failure_pfn =3D addr_to_pfn(mem); + munmap(mem, size); + + /* Fault page into stage2 page tables. */ + guest_read(vcpu, gpa, 0); + + mark_memory_failure(memory_failure_pfn, 0); + + guest_read(vcpu, gpa, EHWPOISON); + munmap(mem, size); + + close(fd); + kvm_vm_free(vm); + + unmark_memory_failure(memory_failure_pfn, 0); +} + int main(int argc, char *argv[]) { unsigned long vm_types, vm_type; @@ -559,4 +623,5 @@ int main(int argc, char *argv[]) test_guest_memfd(vm_type); =20 test_guest_memfd_guest(); + test_memory_failure_guest(); } --=20 2.51.0.788.g6d19910ace-goog