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AJvYcCW+4wNrQnmMpZb7al6yfOIig9mSuUEvVo3+1sDNnilAL3bwzhmeCLALZ1GP/tpyQpw65dKREbne4jK07WT43drNrJs=@vger.kernel.org X-Gm-Message-State: AOJu0Yy1mdg1fSefFtc3vcT/TgdkVS7zX7GewoONTnmKHTJrKsnKaZyb 9ETfldZV86dV2g+Z1ZxnjGBxCAhAYJVVg5FgIQaBbl2yECNBOsp6y/PtDdS0r+A3ILhkerU+n9S TMlJ4pv3iIYyMXGs0bUaESgC9Gw== X-Received: from pjqx4.prod.google.com ([2002:a17:90a:b004:b0:35c:2df3:c081]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4b06:b0:35b:e52a:7d23 with SMTP id 98e67ed59e1d1-35c30117e64mr191331a91.28.1774563925502; Thu, 26 Mar 2026 15:25:25 -0700 (PDT) Date: Thu, 26 Mar 2026 15:24:39 -0700 In-Reply-To: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Developer-Signature: v=1; a=ed25519-sha256; t=1774563861; l=1963; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=+wZOcpFDmRXwMUiTSKOEYcZYo2gBc+x0kj6bHpNQCtY=; b=aIMdopLnLwO2DBw/+/pPTRO0PTRtL85NVIpPoFXjBwUu+m8reLPqJ0xX4iIa55xeC6M1az4Vh 4yReKUF3iOvDQCxU+P/EwvSTm1mCOOA+k1k+K+iQe1qoaGLasqt7PbD X-Mailer: b4 0.14.3 Message-ID: <20260326-gmem-inplace-conversion-v4-30-e202fe950ffd@google.com> Subject: [PATCH RFC v4 30/44] KVM: selftests: Test that truncation does not change shared/private status From: Ackerley Tng 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, jroedel@suse.de, 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 , 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, Ackerley Tng Content-Type: text/plain; charset="utf-8" Add a test to verify that deallocating a page in a guest memfd region via fallocate() with FALLOC_FL_PUNCH_HOLE does not alter the shared or private status of the corresponding memory range. When a page backing a guest memfd mapping is deallocated, e.g., by punching a hole or truncating the file, and then subsequently faulted back in, the new page must inherit the correct shared/private status tracked by guest_memfd. Signed-off-by: Ackerley Tng Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/guest_memfd_conversions_test.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c index 8f09671505b32..f195a202b3785 100644 --- a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c @@ -10,6 +10,7 @@ #include #include "kvm_util.h" +#include "kvm_syscalls.h" #include "kselftest_harness.h" #include "test_util.h" #include "ucall_common.h" @@ -320,6 +321,19 @@ GMEM_CONVERSION_MULTIPAGE_TEST_INIT_SHARED(unallocated_folios, 8) test_convert_to_shared(t, i, 'B', 'C', 'D'); } +/* Truncation should not affect shared/private status. */ +GMEM_CONVERSION_TEST_INIT_SHARED(truncate) +{ + host_do_rmw(t->mem, 0, 0, 'A'); + kvm_fallocate(t->gmem_fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size); + host_do_rmw(t->mem, 0, 0, 'A'); + + test_convert_to_private(t, 0, 'A', 'B'); + + kvm_fallocate(t->gmem_fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0, page_size); + test_private(t, 0, 0, 'A'); +} + int main(int argc, char *argv[]) { TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM)); -- 2.53.0.1018.g2bb0e51243-goog