From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5BFD435E55D; Mon, 31 Aug 2026 00:25:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135924; cv=none; b=Ndojjmgih9PKWmo6m7dkYNswKeLwvbuujm5YHepIBM/Ku9XnkN7ncwn25zHylFtrCYIiXXhuFihQNnEHDxbfRwN93JURt7wsxHAPAgnMIVcP8jsgb1w5p3bPf4fachT7ZwdBH+Pw7GMtx6Svu/h/yMebt2cWtfj9NqUVOg9D43I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135924; c=relaxed/simple; bh=L1SvzQQsKRUvOZ0fQVdIdVUEFR5k64uVcH/NuUMnWr4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=PSJZGOyWBOsIYeGMe1uYAVAv74uBRV0r1f/944D538IkhTekWU1AeYa7d8jhFULB20ahwxhwbD8jxLzii0rd7wnPjzNexqr7xkp5KgSl7M8Y840mKm+gialKXvYCyMkBN4gM2aTUBO89dm6uSAR1C0bcVczCCoTBDV+b9dTvD5M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O/5NBW6O; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O/5NBW6O" Received: by smtp.kernel.org (Postfix) with ESMTPS id 2CB53C2BCF5; Mon, 31 Aug 2026 00:25:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1788135924; bh=L1SvzQQsKRUvOZ0fQVdIdVUEFR5k64uVcH/NuUMnWr4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=O/5NBW6OI201GlvVp10lsHH14kGYEqgCVacehiFDMnVFB0S/+QISvCCMgW5J7NISs M5dTwBDLWrF2IAOLExZGYZDrRmzvgcbBow1fEAn+tmL3jrUoRBHQ/+153Pg2ZNkim4 /Gd5RX8JS86jbiXhlEBAy2lPMiv94sYO2BPRXFgWNgyQmX6UPSftMJPq0vI4Ri/fy3 d1CH7KR04eOiQ2yIAsOI6GajGrRt4sNTBv9LiBT06ZbFUuUlG9hfkjVk9F36gKi2e1 CiG3O000yZiN5XrtSasyHBxzLNN6V9QShpqA/7vPvFHbUVtrzveSYCmoJO6RipGyvp mCYeEvhB/pOJQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CF04C61DE4; Mon, 31 Aug 2026 00:25:24 +0000 (UTC) From: Ackerley Tng via B4 Relay Date: Sun, 30 Aug 2026 17:25:45 -0700 Subject: [PATCH v12 44/45] KVM: selftests: Update private_mem_conversions_test for in-place conversions Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260830-gmem-inplace-conversion-v12-44-85e5fd25252a@google.com> References: <20260830-gmem-inplace-conversion-v12-0-85e5fd25252a@google.com> In-Reply-To: <20260830-gmem-inplace-conversion-v12-0-85e5fd25252a@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , John Hubbard , Peter Xu , tarunsahu@google.com, Randy Dunlap , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , Fuad Tabba , Vlastimil Babka , Baoquan He Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, Ackerley Tng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1788135916; l=5680; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=1X1DA4tCAHh53esF+mJakIrdUfA/0k+CNqzh025SQ+I=; b=q2PZoPyAMrhu+u+7JvbSLoJN9cFAttmsbb84heBDBlERga8e9Hybf0q4RUT8pEXtUMNU1LnQn xooi06cBSXdCr8UzLSYDo4mk68lH7DL7w3WrvB1d1g3KSsm0AjYYexF X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com From: Ackerley Tng Update private_mem_conversions_test for in-place conversions. In-place conversions support is detected in selftests with kvm_has_gmem_attributes. With in-place conversions, specifying userspace_addr from some other memory provider that is not the guest_memfd associated with the memslot is a user error, since KVM will only use both shared and private memory from the guest_memfd. Hence, when kvm_has_gmem_attributes, only test in-place conversions with single backing, where guest_memfd provides both shared and private memory. For single backing, guest_memfd must be created with GUEST_MEMFD_FLAG_MMAP. Initialize the guest_memfd as shared to align with how memory would default to shared when shared/private state was tracked at the VM level (the test expects this, it was written for non-in-place-conversions). When handling a hypercall to set attributes, use vm_mem_set_memory_attributes() to send the ioctl to the guest_memfd instead of the VM. When testing in-place conversions (single-backing), don't allow the user to configure src_type, since src_type will be ignored. Don't use src_type to determine alignment for rounding up per-cpu test memory size, since guest_memfd's backing page size is always the system PAGE_SIZE. Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Signed-off-by: Ackerley Tng --- .../kvm/x86/private_mem_conversions_test.c | 57 +++++++++++++++++----- 1 file changed, 44 insertions(+), 13 deletions(-) diff --git a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c index cf50e9a332c5b..33b610383693b 100644 --- a/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c +++ b/tools/testing/selftests/kvm/x86/private_mem_conversions_test.c @@ -306,9 +306,12 @@ static void handle_exit_hypercall(struct kvm_vcpu *vcpu) if (do_fallocate) vm_guest_mem_fallocate(vm, gpa, size, map_shared); - if (set_attributes) - vm_set_memory_attributes(vm, gpa, size, - map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE); + if (set_attributes) { + u64 attrs = map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE; + + vm_mem_set_memory_attributes(vm, gpa, size, attrs); + } + run->hypercall.ret = 0; } @@ -352,8 +355,21 @@ static void *__test_mem_conversions(void *__vcpu) size_t nr_bytes = min_t(size_t, vm->page_size, size - i); u8 *hva = addr_gpa2hva(vm, gpa + i); - /* In all cases, the host should observe the shared data. */ - memcmp_h(hva, gpa + i, uc.args[3], nr_bytes); + if (kvm_has_gmem_attributes && + uc.args[0] == SYNC_PRIVATE) { + TEST_EXPECT_SIGBUS(READ_ONCE(*hva)); + } else { + /* + * If not testing in-place conversion + * (dual backing), the host should + * always observe shared data, since the + * shared memory is a separate page. + * + * For SYNC_SHARED, test that the host + * can see shared memory. + */ + memcmp_h(hva, gpa + i, uc.args[3], nr_bytes); + } /* For shared, write the new pattern to guest memory. */ if (uc.args[0] == SYNC_SHARED) @@ -369,20 +385,29 @@ static void *__test_mem_conversions(void *__vcpu) } } +/* Align each vCPU's chunk of memory naturally to the size of the backing store. */ +static size_t compute_per_cpu_size(enum vm_mem_backing_src_type src_type) +{ + size_t alignment; + + if (kvm_has_gmem_attributes) + alignment = getpagesize(); + else + alignment = get_backing_src_pagesz(src_type); + + return align_up(PER_CPU_DATA_SIZE, max_t(size_t, SZ_2M, alignment)); +} + static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_vcpus, u32 nr_memslots) { - /* - * Allocate enough memory so that each vCPU's chunk of memory can be - * naturally aligned with respect to the size of the backing store. - */ - const size_t alignment = max_t(size_t, SZ_2M, get_backing_src_pagesz(src_type)); - const size_t per_cpu_size = align_up(PER_CPU_DATA_SIZE, alignment); + const size_t per_cpu_size = compute_per_cpu_size(src_type); const size_t memfd_size = per_cpu_size * nr_vcpus; const size_t slot_size = memfd_size / nr_memslots; struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; pthread_t threads[KVM_MAX_VCPUS]; struct kvm_vm *vm; + u64 gmem_flags; int memfd, i; const struct vm_shape shape = { @@ -397,12 +422,16 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE)); - memfd = vm_create_guest_memfd(vm, memfd_size, 0); + gmem_flags = 0; + if (kvm_has_gmem_attributes) + gmem_flags = GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED; + + memfd = vm_create_guest_memfd(vm, memfd_size, gmem_flags); for (i = 0; i < nr_memslots; i++) vm_mem_add(vm, src_type, BASE_DATA_GPA + slot_size * i, BASE_DATA_SLOT + i, slot_size / vm->page_size, - KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, 0); + KVM_MEM_GUEST_MEMFD, memfd, slot_size * i, gmem_flags); for (i = 0; i < nr_vcpus; i++) { gpa_t gpa = BASE_DATA_GPA + i * per_cpu_size; @@ -462,6 +491,8 @@ int main(int argc, char *argv[]) while ((opt = getopt(argc, argv, "hm:s:n:")) != -1) { switch (opt) { case 's': + TEST_ASSERT(!kvm_has_gmem_attributes, + "src_type is only configurable when testing without in-place conversion"); src_type = parse_backing_src_type(optarg); break; case 'n': -- 2.55.0.897.gb25b4bd76c-goog