Hi Xingtao,
Thank you for reproducing this -- I agree with your conclusion and will
send a v2 patchset momentarily.
Thank you,
Gregor
On Thu, Jun 27, 2024 at 5:44 PM Xingtao Yao (Fujitsu) <
yaoxt.f...@fujitsu.com> wrote:
> Hi, Gregor
>
>
>
> >rom: file fw_payload.bin: read error: rc=2147479552 (expected 2303760392)
> >qemu-system-riscv64: could not load firmware 'fw_payload.bin'
>
> Thanks, I was able to reproduce the problem when the images size is
> larger than 2147479552.
>
>
>
> I found that in my test environment, the maximum value returned by a read
> operation is 2147479552,
>
> which was affected by the operating system.
>
>
>
> We can find this limitation in the man page:
>
> NOTES
>
> The types size_t and ssize_t are, respectively, unsigned and
> signed integer data types specified by POSIX.1.
>
>
>
> On Linux, read() (and similar system calls) will transfer at most
> 0x7ffff000 (2,147,479,552) bytes, returning the number of bytes actually
> transferred. (This is true on both
>
> 32-bit and 64-bit systems.)
>
>
>
>
>
> > + do {
>
> > + rc = read(fd, &rom->data[sz], rom->datasize);
>
> > + if (rc == -1) {
>
> > + fprintf(stderr, "rom: file %-20s: read error: %s\n",
>
> > + rom->name, strerror(errno));
>
> > + goto err;
>
> > + }
>
> > + sz += rc;
>
> > + } while (sz != rom->datasize);
>
> I think we can use load_image_size() instead.
>
>
>
>
>
>
>
>
>
> *From:* Gregor Haas <gregorhaas1...@gmail.com>
> *Sent:* Friday, June 28, 2024 1:35 AM
> *To:* Yao, Xingtao/姚 幸涛 <yaoxt.f...@fujitsu.com>
> *Cc:* qemu-devel@nongnu.org; phi...@linaro.org;
> richard.hender...@linaro.org
> *Subject:* Re: [PATCH] hw/core/loader: allow loading larger ROMs
>
>
>
> Hi Xingtao,
>
> > Can you reproduce this issue?
> Absolutely! I encountered this when trying to load an OpenSBI payload
> firmware using the bios option for the QEMU RISC-V virt board. These
> payload firmwares bundle the entire next boot stage, which in my case is a
> build of the Linux kernel (which is a standard configuration, supported by
> tools such as Buildroot [1]). My kernel (configured with the default 64-bit
> RISC-V configuration) comes in at 9.8M, which is copied into the OpenSBI
> firmware of final size 10M. Then, I run the following QEMU command:
>
> qemu-system-riscv64 -machine virt -m 4G -nographic -bios fw_payload.bin
>
> and get the following output:
>
> rom: file fw_payload.bin: read error: rc=2147479552 (expected 2303760392)
> qemu-system-riscv64: could not load firmware 'fw_payload.bin'
>
> This is from my development machine, running Arch Linux with kernel 6.9.6
> and root filesystem ZFS 2.2.4. Please let me know if you'd like me to make
> a minimal reproducer for this, or if you need any more information.
>
> Thanks,
> Gregor
>
> [1]
> https://github.com/buildroot/buildroot/blob/master/boot/opensbi/Config.in#L95
>
>
>
> On Wed, Jun 26, 2024 at 11:11 PM Xingtao Yao (Fujitsu) <
> yaoxt.f...@fujitsu.com> wrote:
>
> Hi, Gregor
> >
> > The read() syscall is not guaranteed to return all data from a file. The
> > default ROM loader implementation currently does not take this into
> account,
> > instead failing if all bytes are not read at once. This change wraps the
> > read() syscall in a do/while loop to ensure all bytes of the ROM are
> read.
> Can you reproduce this issue?
>
> Thanks
> Xingtao
>
>
