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envelope-from=nnmlinux@linux.ibm.com; helo=mx0b-001b2d01.pphosted.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 17/08/26 3:57 PM, uverma@linux.ibm.com wrote: > From: Utkarsh Verma > > Add a new public API load_elf_ram_sym_buf() that loads an ELF > image from a caller-supplied memory buffer rather than a file path. > The implementation writes the buffer to an anonymous memfd, then > reuses the existing load_elf32/load_elf64 paths. > > To support per-segment inspection by callers (e.g. detecting VoF > firmware segments), extend the internal load_elf{32,64} template > (elf_ops.h.inc) with an optional segment_fn_t callback that is > invoked once for every PT_LOAD segment after its load address is > resolved. Returning false from the callback aborts the load with > ELF_LOAD_FAILED. > > AI-used-for: code > Signed-off-by: Utkarsh Verma > --- > hw/core/loader.c | 77 ++++++++++++++++++++++++++++++++++++++-- > include/hw/core/loader.h | 30 ++++++++++++++++ > include/hw/elf_ops.h.inc | 12 ++++++- > 3 files changed, 116 insertions(+), 3 deletions(-) > > diff --git a/hw/core/loader.c b/hw/core/loader.c > index 5cbfba0a86..4e4e9764a3 100644 > --- a/hw/core/loader.c > +++ b/hw/core/loader.c > @@ -43,6 +43,7 @@ > */ > > #include "qemu/osdep.h" > +#include "qemu/memfd.h" > #include "qemu/datadir.h" > #include "qemu/error-report.h" > #include "qapi/error.h" > @@ -510,12 +511,14 @@ ssize_t load_elf_ram_sym(const char *filename, > ret = load_elf64(filename, fd, elf_note_fn, > translate_fn, translate_opaque, must_swab, > pentry, lowaddr, highaddr, pflags, elf_machine, > - clear_lsb, data_swab, as, load_rom, sym_cb); > + clear_lsb, data_swab, as, load_rom, sym_cb, > + NULL, NULL); > } else { > ret = load_elf32(filename, fd, elf_note_fn, > translate_fn, translate_opaque, must_swab, > pentry, lowaddr, highaddr, pflags, elf_machine, > - clear_lsb, data_swab, as, load_rom, sym_cb); > + clear_lsb, data_swab, as, load_rom, sym_cb, > + NULL, NULL); > } > > if (ret > 0) { > @@ -527,6 +530,76 @@ ssize_t load_elf_ram_sym(const char *filename, > return ret; > } > > +ssize_t load_elf_ram_sym_buf(const uint8_t *buf, size_t buflen, > + uint64_t (*elf_note_fn)(void *, void *, bool), > + uint64_t (*translate_fn)(void *, uint64_t), > + void *translate_opaque, uint64_t *pentry, > + uint64_t *lowaddr, uint64_t *highaddr, > + uint32_t *pflags, int elf_data_order, > + int elf_machine, int clear_lsb, int data_swab, > + AddressSpace *as, bool load_rom, > + symbol_fn_t sym_cb, > + segment_fn_t segment_fn, void *segment_opaque) > +{ > + const int host_data_order = HOST_BIG_ENDIAN ? ELFDATA2MSB : ELFDATA2LSB; > + int fd, must_swab; > + ssize_t ret = ELF_LOAD_FAILED; > + uint8_t e_ident[EI_NIDENT]; > + > + fd = memfd_create("qemu-elf-buf", MFD_CLOEXEC); The memfd_create() is Linux-specific. qemu/memfd.h only exposes the direct memfd_create() declaration for Linux configurations, so this also appears to break non-Linux system builds. Could this use an existing portable QEMU temporary-fd abstraction, or alternatively could the ELF loader be factored so the common parser accepts an fd/buffer directly? It seems undesirable for a generic loader API to require Linux memfd support. OR If it is an arch specific design decision, then we need to document it. > + if (fd < 0) { > + error_report("load_elf_ram_sym_buf: memfd_create: %s", strerror(errno)); > + return ELF_LOAD_FAILED; > + } > + > + if (write(fd, buf, buflen) != (ssize_t)buflen) { A single write() is not guaranteed to consume the whole buffer and can be interrupted. Also, if buflen > SSIZE_MAX, the cast used for comparison is problematic. Please use the appropriate QEMU full-write helper (or loop handling short writes/EINTR). > + error_report("load_elf_ram_sym_buf: write: %s", strerror(errno)); > + goto fail; > + } > + > + lseek(fd, 0, SEEK_SET); > + if (read(fd, e_ident, sizeof(e_ident)) != sizeof(e_ident)) { > + goto fail; > + } > + if (e_ident[0] != ELFMAG0 || > + e_ident[1] != ELFMAG1 || > + e_ident[2] != ELFMAG2 || > + e_ident[3] != ELFMAG3) { > + ret = ELF_LOAD_NOT_ELF; > + goto fail; > + } > + > + if (elf_data_order != ELFDATANONE && elf_data_order != e_ident[EI_DATA]) { > + ret = ELF_LOAD_WRONG_ENDIAN; > + goto fail; > + } > + > + must_swab = host_data_order != e_ident[EI_DATA]; > + > + lseek(fd, 0, SEEK_SET); both lseek call errors need to be handled. > + if (e_ident[EI_CLASS] == ELFCLASS64) { > + ret = load_elf64("(buffer)", fd, elf_note_fn, > + translate_fn, translate_opaque, must_swab, > + pentry, lowaddr, highaddr, pflags, elf_machine, > + clear_lsb, data_swab, as, load_rom, sym_cb, > + segment_fn, segment_opaque); > + } else { > + ret = load_elf32("(buffer)", fd, elf_note_fn, > + translate_fn, translate_opaque, must_swab, > + pentry, lowaddr, highaddr, pflags, elf_machine, > + clear_lsb, data_swab, as, load_rom, sym_cb, > + segment_fn, segment_opaque); > + } > + > + if (ret > 0) { > + debuginfo_report_elf("(buffer)", fd, 0); > + } > + > + fail: > + close(fd); > + return ret; > +} > + > static void bswap_uboot_header(uboot_image_header_t *hdr) > { > #if !HOST_BIG_ENDIAN > diff --git a/include/hw/core/loader.h b/include/hw/core/loader.h > index d9431e8a8d..b67b2ca013 100644 > --- a/include/hw/core/loader.h > +++ b/include/hw/core/loader.h > @@ -156,6 +156,36 @@ ssize_t load_elf_ram_sym(const char *filename, > int clear_lsb, int data_swab, > AddressSpace *as, bool load_rom, symbol_fn_t sym_cb); > > +/* > + * segment_fn_t: > + * Per-PT_LOAD segment callback for load_elf_ram_sym_buf(). > + */ > +typedef bool (*segment_fn_t)(void *opaque, > + uint64_t paddr, uint64_t vaddr, > + uint64_t filesz, uint64_t memsz); > + > +/* > + * load_elf_ram_sym_buf: > + * @buf: pointer to an in-memory ELF image > + * @buflen: size of @buf in bytes > + * @segment_fn: optional per-PT_LOAD callback > + * @segment_opaque: opaque data passed to @segment_fn > + * > + * Identical to load_elf_ram_sym() but loads from a caller-supplied > + * memory buffer instead of a file. All other parameters have the > + * same meaning as load_elf_ram_sym(). > + */ > +ssize_t load_elf_ram_sym_buf(const uint8_t *buf, size_t buflen, > + uint64_t (*elf_note_fn)(void *, void *, bool), > + uint64_t (*translate_fn)(void *, uint64_t), > + void *translate_opaque, uint64_t *pentry, > + uint64_t *lowaddr, uint64_t *highaddr, > + uint32_t *pflags, int elf_data_order, > + int elf_machine, int clear_lsb, int data_swab, > + AddressSpace *as, bool load_rom, > + symbol_fn_t sym_cb, > + segment_fn_t segment_fn, void *segment_opaque); > + > /** load_elf_as: > * Same as load_elf_ram_sym(), but always loads the elf as ROM > */ > diff --git a/include/hw/elf_ops.h.inc b/include/hw/elf_ops.h.inc > index 044e72de2a..a2c9b52bf9 100644 > --- a/include/hw/elf_ops.h.inc > +++ b/include/hw/elf_ops.h.inc > @@ -321,7 +321,9 @@ static ssize_t glue(load_elf, SZ)(const char *name, int fd, > uint32_t *pflags, int elf_machine, > int clear_lsb, int data_swab, > AddressSpace *as, bool load_rom, > - symbol_fn_t sym_cb) > + symbol_fn_t sym_cb, > + segment_fn_t segment_fn, > + void *segment_opaque) > { > struct elfhdr ehdr; > struct elf_phdr *phdr = NULL, *ph; > @@ -504,6 +506,14 @@ static ssize_t glue(load_elf, SZ)(const char *name, int fd, > addr = ph->p_paddr; > } > > + if (segment_fn) { > + if (!segment_fn(segment_opaque, addr, ph->p_vaddr, > + file_size, mem_size)) { > + ret = ELF_LOAD_FAILED; > + goto fail; > + } > + } > + > if (data_swab) { > elf_word j; > for (j = 0; j < file_size; j += (1 << data_swab)) { Thanks, Narayana Murty N