mirror of
https://chromium.googlesource.com/crosvm/crosvm
synced 2025-02-09 20:04:20 +00:00
Reland "swap: add userfaultfd wrapper"
origin: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/3895235 userfaultfd enables applications to handle page faults on designated memory area. vmm-swap feature uses userfaultfd to catch page fault event and swap in the guest memory from the swap file. design document: go/tanooki-phase1-dd BUG=b:215093219 TEST=cargo build --features=swap Change-Id: I36ecfe9be988a4bc451f8edaf2ab48e25c6600f4 Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/4016142 Commit-Queue: Shin Kawamura <kawasin@google.com> Reviewed-by: David Stevens <stevensd@chromium.org> Reviewed-by: Dennis Kempin <denniskempin@google.com>
This commit is contained in:
Shintaro Kawamura
crosvm LUCI
parent
ba3e2fa852
commit
67390a05fb
6 changed files with 293 additions and 1 deletions
129
Cargo.lock
generated
129
Cargo.lock
generated
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@ -230,6 +230,25 @@ dependencies = [
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"syn 1.0.103",
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]
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[[package]]
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name = "bindgen"
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version = "0.60.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "062dddbc1ba4aca46de6338e2bf87771414c335f7b2f2036e8f3e9befebf88e6"
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dependencies = [
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"bitflags",
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"cexpr",
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"clang-sys",
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"lazy_static",
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"lazycell",
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"peeking_take_while",
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"proc-macro2",
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"quote 1.0.21",
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"regex",
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"rustc-hash",
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"shlex",
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]
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[[package]]
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name = "bit_field"
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version = "0.1.0"
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@ -312,6 +331,15 @@ dependencies = [
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"jobserver",
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]
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[[package]]
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name = "cexpr"
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version = "0.6.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"
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dependencies = [
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"nom",
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]
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[[package]]
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name = "cfg-if"
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version = "1.0.0"
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@ -332,6 +360,17 @@ dependencies = [
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"winapi",
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]
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[[package]]
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name = "clang-sys"
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version = "1.4.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "fa2e27ae6ab525c3d369ded447057bca5438d86dc3a68f6faafb8269ba82ebf3"
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dependencies = [
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"glob",
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"libc",
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"libloading",
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]
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[[package]]
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name = "clap"
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version = "2.34.0"
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@ -532,6 +571,7 @@ dependencies = [
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"serde_json",
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"serde_keyvalue",
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"static_assertions",
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"swap",
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"sync",
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"tempfile",
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"terminal_size",
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@ -606,7 +646,7 @@ version = "3.2.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "b37feaa84e6861e00a1f5e5aa8da3ee56d605c9992d33e082786754828e20865"
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dependencies = [
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"nix",
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"nix 0.24.2",
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"winapi",
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]
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@ -975,6 +1015,12 @@ dependencies = [
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"wasi 0.11.0+wasi-snapshot-preview1",
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]
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[[package]]
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name = "glob"
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version = "0.3.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
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[[package]]
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name = "gpu_display"
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version = "0.1.0"
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@ -1172,6 +1218,12 @@ version = "1.4.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
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[[package]]
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name = "lazycell"
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version = "1.3.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
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[[package]]
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name = "libc"
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version = "0.2.126"
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@ -1206,6 +1258,16 @@ dependencies = [
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"once_cell",
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]
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[[package]]
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name = "libloading"
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version = "0.7.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "efbc0f03f9a775e9f6aed295c6a1ba2253c5757a9e03d55c6caa46a681abcddd"
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dependencies = [
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"cfg-if",
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"winapi",
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]
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[[package]]
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name = "libslirp-sys"
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version = "4.2.1"
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@ -1406,6 +1468,19 @@ dependencies = [
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"winapi",
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]
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[[package]]
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name = "nix"
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version = "0.23.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "9f866317acbd3a240710c63f065ffb1e4fd466259045ccb504130b7f668f35c6"
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dependencies = [
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"bitflags",
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"cc",
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"cfg-if",
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"libc",
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"memoffset 0.6.5",
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]
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[[package]]
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name = "nix"
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version = "0.24.2"
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@ -1497,6 +1572,12 @@ dependencies = [
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"thiserror",
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]
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[[package]]
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name = "peeking_take_while"
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version = "0.1.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
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[[package]]
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name = "pin-project-lite"
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version = "0.2.9"
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@ -1718,6 +1799,12 @@ dependencies = [
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"thiserror",
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]
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[[package]]
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name = "rustc-hash"
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version = "1.1.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
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[[package]]
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name = "rutabaga_gfx"
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version = "0.1.0"
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@ -1837,6 +1924,12 @@ dependencies = [
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"syn 1.0.103",
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]
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[[package]]
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name = "shlex"
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version = "1.1.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "43b2853a4d09f215c24cc5489c992ce46052d359b5109343cbafbf26bc62f8a3"
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[[package]]
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name = "slab"
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version = "0.4.7"
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@ -1864,6 +1957,15 @@ version = "0.8.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
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[[package]]
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name = "swap"
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version = "0.1.0"
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dependencies = [
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"base",
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"libc",
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"userfaultfd",
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]
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[[package]]
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name = "syn"
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version = "0.11.11"
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@ -2062,6 +2164,31 @@ dependencies = [
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"usb_sys",
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]
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[[package]]
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name = "userfaultfd"
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version = "0.5.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "fee2cdd3f8bdd0b98d7aa9ace35e7214a71888229d60c1cd1cd71b7c09c089d0"
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dependencies = [
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"bitflags",
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"cfg-if",
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"libc",
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"nix 0.23.1",
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"thiserror",
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"userfaultfd-sys",
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]
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[[package]]
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name = "userfaultfd-sys"
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version = "0.4.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "d2cbcf2717fa856a7226499babbbccb07353ea2fc2b27defd38bd13b1227cc78"
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dependencies = [
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"bindgen",
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"cc",
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"cfg-if",
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]
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[[package]]
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name = "uuid"
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version = "0.8.2"
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@ -90,6 +90,7 @@ members = [
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"resources",
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"rutabaga_gfx",
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"serde_keyvalue",
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"swap",
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"system_api",
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"third_party/vmm_vhost",
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"tpm2-sys",
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"panic-memfd",
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"power-monitor-powerd",
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"slirp",
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"swap",
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"tpm",
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"vaapi",
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"video-decoder",
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@ -395,6 +397,9 @@ aarch64 = { path = "aarch64" }
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minijail = "*" # provided by ebuild
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p9 = "*"
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[target.'cfg(target_os="linux")'.dependencies]
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swap = { path = "swap", optional = true }
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[target.'cfg(windows)'.dependencies]
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anti_tamper = { path = "anti_tamper" }
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cros_async = { path = "cros_async" }
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10
swap/Cargo.toml
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10
swap/Cargo.toml
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@ -0,0 +1,10 @@
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[package]
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name = "swap"
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version = "0.1.0"
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authors = ["The Chromium OS Authors"]
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edition = "2021"
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[dependencies]
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base = { path = "../base" }
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libc = "*"
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userfaultfd = "0.5.0"
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11
swap/src/lib.rs
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11
swap/src/lib.rs
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@ -0,0 +1,11 @@
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// Copyright 2022 The ChromiumOS Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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//! crate for the vmm-swap feature.
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// TODO(kawasin): warn dead_code again after swap feature is done.
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#![allow(dead_code)]
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#![deny(missing_docs)]
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mod userfaultfd;
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138
swap/src/userfaultfd.rs
Normal file
138
swap/src/userfaultfd.rs
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@ -0,0 +1,138 @@
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// Copyright 2022 The ChromiumOS Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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//! Provides wrapper of userfaultfd crate for vmm-swap feature.
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#![deny(missing_docs)]
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use std::convert::From;
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use std::os::unix::io::AsRawFd;
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use base::AsRawDescriptor;
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use base::RawDescriptor;
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pub use userfaultfd::Error as UffdError;
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pub use userfaultfd::Event as UffdEvent;
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use userfaultfd::FeatureFlags;
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use userfaultfd::IoctlFlags;
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use userfaultfd::Result;
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use userfaultfd::Uffd;
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use userfaultfd::UffdBuilder;
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/// Wrapper for [`userfaultfd::Uffd`] to be used in the vmm-swap feature.
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///
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/// # Safety
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///
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/// The userfaultfd operations (`UFFDIO_COPY` and `UFFDIO_ZEROPAGE`) looks unsafe since it fills a
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/// memory content directly. But they actually are not unsafe operation but `UFFDIO_REGISTER` should
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/// be the unsafe operation for Rust memory safety.
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///
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/// According to [the Rust document](https://doc.rust-lang.org/nomicon/uninitialized.html),
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///
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/// > All runtime-allocated memory in a Rust program begins its life as uninitialized.
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///
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/// The userfaultfd operations actually does not change/overwrite the existing memory contents but
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/// they just setup the "uninitialized" pages. If the page was already initialized, the userfaultfd
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/// operations fail and return EEXIST error (which is not documented unfortunately). So they
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/// originally does not affect the Rust memory safety.
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///
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/// The "uninitialized" page in this context has 2 patterns:
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///
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/// 1. pages which is never touched or,
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/// 2. pages which is never touched after MADV_REMOVE
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///
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/// Filling the (1) pages with any contents should not affect the Rust memory safety.
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///
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/// Filling the (2) pages potentially may break the memory used by Rust. But the safety should be
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/// examined at `MADV_REMOVE` and `UFFDIO_REGISTER` timing.
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pub struct Userfaultfd {
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uffd: Uffd,
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}
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impl Userfaultfd {
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/// Creates a new userfaultfd.
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pub fn new() -> Result<Self> {
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let uffd = UffdBuilder::new()
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.close_on_exec(true)
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.non_blocking(true)
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.user_mode_only(false)
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.require_features(
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FeatureFlags::EVENT_FORK | FeatureFlags::MISSING_SHMEM | FeatureFlags::EVENT_REMOVE,
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)
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.create()?;
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Ok(Self { uffd })
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}
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/// Register a range of memory to the userfaultfd.
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///
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/// After this registration, any page faults on the range will be caught by the userfaultfd.
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///
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/// # Arguments
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///
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/// * `addr` - the starting address of the range of memory.
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/// * `len` - the length in bytes of the range of memory.
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///
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/// # Safety
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///
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/// [addr, addr+len) must lie within a [MemoryMapping](base::MemoryMapping), and that mapping
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/// must live for the lifespan of the userfaultfd kernel object (which may be distinct from the
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/// `Userfaultfd` rust object in this process).
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pub unsafe fn register(&self, addr: usize, len: usize) -> Result<IoctlFlags> {
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self.uffd.register(addr as *mut libc::c_void, len)
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}
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/// Initialize page(s) and fill it with zero.
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///
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/// # Arguments
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///
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/// * `addr` - the starting address of the page(s) to be initialzed with zero.
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/// * `len` - the length in bytes of the page(s).
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/// * `wake` - whether or not to unblock the faulting thread.
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pub fn zero(&self, addr: usize, len: usize, wake: bool) -> Result<usize> {
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// safe because zeroing untouched pages does not break the Rust memory safety since "All
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// runtime-allocated memory in a Rust program begins its life as uninitialized."
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// https://doc.rust-lang.org/nomicon/uninitialized.html
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unsafe { self.uffd.zeropage(addr as *mut libc::c_void, len, wake) }
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}
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/// Copy the `data` to the page(s) starting from `addr`.
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///
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/// # Arguments
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///
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/// * `addr` - the starting address of the page(s) to be initialzed with data.
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/// * `len` - the length in bytes of the page(s).
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/// * `data` - the starting address of the content.
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/// * `wake` - whether or not to unblock the faulting thread.
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pub fn copy(&self, addr: usize, len: usize, data: *const u8, wake: bool) -> Result<usize> {
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// safe because filling untouched pages with data does not break the Rust memory safety
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// since "All runtime-allocated memory in a Rust program begins its life as uninitialized."
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// https://doc.rust-lang.org/nomicon/uninitialized.html
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unsafe {
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self.uffd.copy(
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data as *const libc::c_void,
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addr as *mut libc::c_void,
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len,
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wake,
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)
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}
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}
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/// Read an event from the userfaultfd.
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///
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/// Return `None` immediately if no events is ready to read.
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pub fn read_event(&self) -> Result<Option<UffdEvent>> {
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self.uffd.read_event()
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}
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}
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impl From<Uffd> for Userfaultfd {
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fn from(uffd: Uffd) -> Self {
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Self { uffd }
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}
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}
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impl AsRawDescriptor for Userfaultfd {
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fn as_raw_descriptor(&self) -> RawDescriptor {
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self.uffd.as_raw_fd()
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}
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}
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@ -71,6 +71,7 @@ WIN64_DISABLED_CRATES = [
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"p9",
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"qcow_utils",
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"rutabaga_gralloc",
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"swap",
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"system_api_stub",
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"tpm2-sys",
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"tpm2",
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Loading…
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