From nobody Sat Oct 4 01:39:27 2025 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 985032253F9; Fri, 22 Aug 2025 07:06:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755846398; cv=none; b=H+fDVKjl5Qe0rRvvEiPFKcxfpN5XrcyxyaRTMqxmvPy2HvvciMdaV4wzQjL5YPXepi5yn5u1TezlXC/p8PgzlYY9MSKfT3E1Z/ZwKnJ5SGhbZcPKZnAr5gtvNzMEYONay+U/SIy0Hv2LKksOlzF/q3Sslhyl8pqe2B41rT473ac= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755846398; c=relaxed/simple; bh=vK1Fc9hq2tBF3cBCzzIiljNe8N3mobe9b1tyZxZ4buU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rTn2ZoefVl73aruxdfV3C6x6T6fXeAm0kgJTWJLDvbXDKGrcFRr5prPqqbJbmQQUDtnRkT5x9MzZ2dsj5s3gfFy8YykIkG+75qsrcjxeheKGgAMubsfxi8qy5qqAjzzfvDmFTGQjRgejFkuuOYs1wKCpNynZfKCNuc2M4LKse7c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=gdV1tyce; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="gdV1tyce" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1755846397; x=1787382397; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=vK1Fc9hq2tBF3cBCzzIiljNe8N3mobe9b1tyZxZ4buU=; b=gdV1tyceWLlO52sClX9gUdm/86iKswrVRVRmFCTznxgtoIwRHczlLDyy rJnvppcevpYVSH4qjmCD8Q5v5feKEw4y7uwufVNlu1RW4dJqAWnhZHml/ TsXFte2A5ZWQzzYQLWSm6aIyCuFq0q1uPPQdAM5pYS8vRtneSEGnD8/Kg MpIk7mmhfA37zhIQqkpu3wFSgkHVG1Y/6BcLqjvriwCXIPdIYn7PdDvf/ 9DrgiFZbD035juDPbGY9CT6djBR00JHEXoT6tHAbcaaP4zIemkg2HcQvn Rc3I994WKbPvXpwDSKuYHiXqUyzuJCRubQHYOq1qG9o3G80yUoDFFfjzg Q==; X-CSE-ConnectionGUID: CkABdel/STCriOejPEsGlg== X-CSE-MsgGUID: N9f47Mz7S6qCujcg9JIqIA== X-IronPort-AV: E=McAfee;i="6800,10657,11529"; a="58216274" X-IronPort-AV: E=Sophos;i="6.17,309,1747724400"; d="scan'208";a="58216274" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Aug 2025 00:06:36 -0700 X-CSE-ConnectionGUID: gcF2yLkNSUSlOftyS9kDBw== X-CSE-MsgGUID: 1MzEeu0TSqiaScYbMY6pxw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.17,309,1747724400"; d="scan'208";a="172829670" Received: from yzhao56-desk.sh.intel.com ([10.239.47.19]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Aug 2025 00:06:34 -0700 From: Yan Zhao To: pbonzini@redhat.com, seanjc@google.com Cc: reinette.chatre@intel.com, rick.p.edgecombe@intel.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Yan Zhao Subject: [PATCH v2 3/3] KVM: selftests: Test prefault memory during concurrent memslot removal Date: Fri, 22 Aug 2025 15:05:54 +0800 Message-ID: <20250822070554.26523-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20250822070305.26427-1-yan.y.zhao@intel.com> References: <20250822070305.26427-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Test prefault memory during concurrent memslot removal. Add a new param "remove_slot" to pre_fault_memory() to indicate testing concurrent memslot removal. When "remove_slot" is set: Create a remove_thread which deletes the test slot concurrently while the main thread is executing ioctl KVM_PRE_FAULT_MEMORY on the test slot memory range. Introduce variables "delete_thread_ready" and "prefault_ready" to synchronize the slot removal and ioctl KVM_PRE_FAULT_MEMORY. When the concurrency is achieved, ioctl KVM_PRE_FAULT_MEMORY should return the error EAGAIN. Otherwise, the ioctl should succeed as in cases where remove_slot is not set. Retry ioctl KVM_PRE_FAULT_MEMORY upon receiving EAGAIN. Since the memslot should have been successfully removed during the retry, EFAULT or ENOENT should be returned depending on whether the prefault is for private or shared memory. Split the existing "gpa" parameter in pre_fault_memory() into "base_gpa" and "offset" to facilitate adding the test slot back to "base_gpa" after the test concludes, ensuring that subsequent tests are not affected. Signed-off-by: Yan Zhao --- .../selftests/kvm/pre_fault_memory_test.c | 94 +++++++++++++++---- 1 file changed, 78 insertions(+), 16 deletions(-) diff --git a/tools/testing/selftests/kvm/pre_fault_memory_test.c b/tools/te= sting/selftests/kvm/pre_fault_memory_test.c index 0350a8896a2f..56e65feb4c8c 100644 --- a/tools/testing/selftests/kvm/pre_fault_memory_test.c +++ b/tools/testing/selftests/kvm/pre_fault_memory_test.c @@ -10,12 +10,16 @@ #include #include #include +#include =20 /* Arbitrarily chosen values */ #define TEST_SIZE (SZ_2M + PAGE_SIZE) #define TEST_NPAGES (TEST_SIZE / PAGE_SIZE) #define TEST_SLOT 10 =20 +static bool prefault_ready; +static bool delete_thread_ready; + static void guest_code(uint64_t base_gpa) { volatile uint64_t val __used; @@ -30,17 +34,47 @@ static void guest_code(uint64_t base_gpa) GUEST_DONE(); } =20 -static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 gpa, u64 size, - u64 left) +static void *remove_slot_worker(void *data) +{ + struct kvm_vcpu *vcpu =3D (struct kvm_vcpu *)data; + + WRITE_ONCE(delete_thread_ready, true); + + while (!READ_ONCE(prefault_ready)) + cpu_relax(); + + vm_mem_region_delete(vcpu->vm, TEST_SLOT); + + WRITE_ONCE(delete_thread_ready, false); + return NULL; +} + +static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 base_gpa, u64 offs= et, + u64 size, u64 left, bool private, bool remove_slot) { struct kvm_pre_fault_memory range =3D { - .gpa =3D gpa, + .gpa =3D base_gpa + offset, .size =3D size, .flags =3D 0, }; - u64 prev; + pthread_t remove_thread; + bool remove_hit =3D false; int ret, save_errno; + u64 prev; =20 + if (remove_slot) { + pthread_create(&remove_thread, NULL, remove_slot_worker, vcpu); + + while (!READ_ONCE(delete_thread_ready)) + cpu_relax(); + + WRITE_ONCE(prefault_ready, true); + } + + /* + * EAGAIN may be returned if slot removal is performed during + * KVM_PRE_FAULT_MEMORY. + */ do { prev =3D range.size; ret =3D __vcpu_ioctl(vcpu, KVM_PRE_FAULT_MEMORY, &range); @@ -49,18 +83,42 @@ static void pre_fault_memory(struct kvm_vcpu *vcpu, u64= gpa, u64 size, "%sexpecting range.size to change on %s", ret < 0 ? "not " : "", ret < 0 ? "failure" : "success"); - } while (ret >=3D 0 ? range.size : save_errno =3D=3D EINTR); =20 - TEST_ASSERT(range.size =3D=3D left, - "Completed with %lld bytes left, expected %" PRId64, - range.size, left); + if (remove_slot && ret < 0 && save_errno =3D=3D EAGAIN) + remove_hit =3D true; + + } while (ret >=3D 0 ? range.size : ((save_errno =3D=3D EINTR) || (save_er= rno =3D=3D EAGAIN))); =20 - if (left =3D=3D 0) - __TEST_ASSERT_VM_VCPU_IOCTL(!ret, "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm); - else - /* No memory slot causes RET_PF_EMULATE. it results in -ENOENT. */ - __TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno =3D=3D ENOENT, + if (remove_slot) { + pthread_join(remove_thread, NULL); + WRITE_ONCE(prefault_ready, false); + + vm_userspace_mem_region_add(vcpu->vm, VM_MEM_SRC_ANONYMOUS, + base_gpa, TEST_SLOT, TEST_NPAGES, + private ? KVM_MEM_GUEST_MEMFD : 0); + } + + if (remove_hit) { + /* + * Prefault within a removed memory slot range returns + * - EFAULT for private memory or + * - ENOENT for shared memory (due to RET_PF_EMULATE). + */ + __TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno =3D=3D (private ? EFAULT := ENOENT), "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm); + } else { + TEST_ASSERT(range.size =3D=3D left, + "Completed with %lld bytes left, expected %" PRId64, + range.size, left); + + if (left =3D=3D 0) + __TEST_ASSERT_VM_VCPU_IOCTL(!ret, "KVM_PRE_FAULT_MEMORY", + ret, vcpu->vm); + else + /* No memory slot causes RET_PF_EMULATE. it results in -ENOENT. */ + __TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno =3D=3D ENOENT, + "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm); + } } =20 static void __test_pre_fault_memory(unsigned long vm_type, bool private) @@ -97,9 +155,13 @@ static void __test_pre_fault_memory(unsigned long vm_ty= pe, bool private) =20 if (private) vm_mem_set_private(vm, guest_test_phys_mem, TEST_SIZE); - pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, 0); - pre_fault_memory(vcpu, guest_test_phys_mem + SZ_2M, PAGE_SIZE * 2, PAGE_S= IZE); - pre_fault_memory(vcpu, guest_test_phys_mem + TEST_SIZE, PAGE_SIZE, PAGE_S= IZE); + + pre_fault_memory(vcpu, guest_test_phys_mem, 0, SZ_2M, 0, private, true); + pre_fault_memory(vcpu, guest_test_phys_mem, 0, SZ_2M, 0, private, false); + pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, PAGE_SIZE * 2, PAGE_SI= ZE, + private, false); + pre_fault_memory(vcpu, guest_test_phys_mem, TEST_SIZE, PAGE_SIZE, PAGE_SI= ZE, + private, false); =20 vcpu_args_set(vcpu, 1, guest_test_virt_mem); vcpu_run(vcpu); --=20 2.43.2