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charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260428-gmem-inplace-conversion-v5-50-d8608ccfca22@google.com> References: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> In-Reply-To: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@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, ira.weiny@intel.com, 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, tabba@google.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, 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 , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Jason Gunthorpe , Vlastimil Babka 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=1777418714; l=5312; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=bwPTkwZvDxfUUFYwlpNeKbRuK99+tHHLhQpgIWpmwPw=; b=28SKjyLa2IUqWFkTFjnKcnXy6T655u38NWUOOjx5dHDE7NQ0XXqy7HzAEe1gatNHcYlDdkdLP iBUvyWpIELZDJMKOlTTxgvHdfQJaPjRG4mNsaWlhLHBlWjYGDHA1rYg 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 X-Rspam-User: X-Rspamd-Queue-Id: CE6D6100011 X-Rspamd-Server: rspam06 X-Stat-Signature: 1sxyzx66h5xwk7hs8867r4ok19bpn881 X-HE-Tag: 1777418746-277895 X-HE-Meta: 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 3LyIn128 Wge0j68yUsKiiZsgs34G6nM/Mk86HACLHckGMFllmJrh1bBYo3+TL5q8TCeInxZ7lsBFbkYg0ztExxoOUCbXY+nd2eicDZq4brcN/FsZ/HNTqWdqsdT8bnOUs6dc9zVG1s0SbH0MsnOsv1TwKcXD+VUrpsAxHptF8GcRe5SzRz6b/w2aBw8/Vqf2n2P5Cg6H/yS4xdnsFPZi257Yrp4JanTSDwGz28diGH6kFV8Dn8peItlv/5fKzOr3EuF9ouTTZl4/XglCJq+2XBv+1KsC9CrBloYvbpf2e9jZN1focbIUQLP1AVUVh7/qUBb/V77E1ZEUbTYltXmQvVM72fevllc769tP1wjpPkZF/SHxp1LJPDokTwUP7ChTuLhe46sqT75StAj6asziejbVQkG5JWPFR5Hv1jYTmxKFKlzwe6IHLRfxGGxDJvPDttcsuAmlrZJQ653lBf2Svff0Vws+lAehAEQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ackerley Tng Update the private memory conversions selftest to also test conversions that are done "in-place" via per-guest_memfd memory attributes. In-place conversions require the host to be able to mmap() the guest_memfd so that the host and guest can share the same backing physical memory. This includes several updates, that are conditioned on the system supporting per-guest_memfd attributes (kvm_has_gmem_attributes): 1. Set up guest_memfd requesting MMAP and INIT_SHARED. 2. With in-place conversions, the host's mapping points directly to the guest's memory. When the guest converts a region to private, host access to that region is blocked. Update the test to expect a SIGBUS when attempting to access the host virtual address (HVA) of private memory. 3. Use vm_mem_set_memory_attributes(), which chooses how to set memory attributes based on whether kvm_has_gmem_attributes. Restrict the test to using VM_MEM_SRC_SHMEM because guest_memfd's required mmap() flags and page sizes happens to align with those of VM_MEM_SRC_SHMEM. As long as VM_MEM_SRC_SHMEM is used for src_type, vm_mem_add() works as intended. Signed-off-by: Ackerley Tng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- .../kvm/x86/private_mem_conversions_test.c | 46 ++++++++++++++++++---- 1 file changed, 38 insertions(+), 8 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 289ad10063fca..14a25609a8a35 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 +306,14 @@ 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; + u64 flags = kvm_has_gmem_attributes ? + KVM_SET_MEMORY_ATTRIBUTES2_PRESERVE : 0; + + vm_mem_set_memory_attributes(vm, gpa, size, attrs, flags); + } + run->hypercall.ret = 0; } @@ -352,8 +357,20 @@ 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); + /* + * When using per-guest_memfd memory attributes, + * i.e. in-place conversion, host accesses will + * point at guest memory and should SIGBUS when + * guest memory is private. When using per-VM + * attributes, i.e. separate backing for shared + * vs. private, the host should always observe + * the shared data. + */ + if (kvm_has_gmem_attributes && + uc.args[0] == SYNC_PRIVATE) + TEST_EXPECT_SIGBUS(READ_ONCE(*hva)); + else + 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) @@ -382,6 +399,7 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type, u32 nr_v const size_t slot_size = memfd_size / nr_memslots; struct kvm_vcpu *vcpus[KVM_MAX_VCPUS]; pthread_t threads[KVM_MAX_VCPUS]; + u64 gmem_flags; struct kvm_vm *vm; int memfd, i; @@ -397,12 +415,17 @@ 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); + if (kvm_has_gmem_attributes) + gmem_flags = GUEST_MEMFD_FLAG_MMAP | GUEST_MEMFD_FLAG_INIT_SHARED; + else + gmem_flags = 0; + + 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; @@ -452,17 +475,24 @@ static void usage(const char *cmd) int main(int argc, char *argv[]) { - enum vm_mem_backing_src_type src_type = DEFAULT_VM_MEM_SRC; + enum vm_mem_backing_src_type src_type; u32 nr_memslots = 1; u32 nr_vcpus = 1; int opt; TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM)); + src_type = kvm_has_gmem_attributes ? VM_MEM_SRC_SHMEM : + DEFAULT_VM_MEM_SRC; + while ((opt = getopt(argc, argv, "hm:s:n:")) != -1) { switch (opt) { case 's': src_type = parse_backing_src_type(optarg); + TEST_ASSERT(!kvm_has_gmem_attributes || + src_type == VM_MEM_SRC_SHMEM, + "Testing in-place conversions, only %s mem_type supported\n", + vm_mem_backing_src_alias(VM_MEM_SRC_SHMEM)->name); break; case 'n': nr_vcpus = atoi_positive("nr_vcpus", optarg); -- 2.54.0.545.g6539524ca2-goog