From: Thomas Huth <1880355@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1880355] Re: Length restrictions for fw_cfg_dma_transfer?
Date: Tue, 15 Jun 2021 18:17:45 -0000 [thread overview]
Message-ID: <162378106605.14289.15892854993567335771.malone@wampee.canonical.com> (raw)
In-Reply-To: 159029353528.907.11982786579949073896.malonedeb@chaenomeles.canonical.com
Ok, thanks for checking! Closing now.
** Changed in: qemu
Status: Incomplete => Fix Released
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https://bugs.launchpad.net/bugs/1880355
Title:
Length restrictions for fw_cfg_dma_transfer?
Status in QEMU:
Fix Released
Bug description:
For me, this takes close to 3 minutes at 100% CPU:
echo "outl 0x518 0x9596ffff" | ./i386-softmmu/qemu-system-i386 -M q35 -m 32 -nographic -accel qtest -monitor none -serial none -qtest stdio
#0 phys_page_find (d=0x606000035d80, addr=136728041144404) at /exec.c:338
#1 address_space_lookup_region (d=0x606000035d80, addr=136728041144404, resolve_subpage=true) at /exec.c:363
#2 address_space_translate_internal (d=0x606000035d80, addr=136728041144404, xlat=0x7fff1fc0d070, plen=0x7fff1fc0d090, resolve_subpage=true) at /exec.c:382
#3 flatview_do_translate (fv=0x606000035d20, addr=136728041144404, xlat=0x7fff1fc0d070, plen_out=0x7fff1fc0d090, page_mask_out=0x0, is_write=true, is_mmio=true, target_as=0x7fff1fc0ce10, attrs=...)
pment/qemu/exec.c:520
#4 flatview_translate (fv=0x606000035d20, addr=136728041144404, xlat=0x7fff1fc0d070, plen=0x7fff1fc0d090, is_write=true, attrs=...) at /exec.c:586
#5 flatview_write_continue (fv=0x606000035d20, addr=136728041144404, attrs=..., ptr=0x7fff1fc0d660, len=172, addr1=136728041144400, l=172, mr=0x557fd54e77e0 <io_mem_unassigned>)
pment/qemu/exec.c:3160
#6 flatview_write (fv=0x606000035d20, addr=136728041144064, attrs=..., buf=0x7fff1fc0d660, len=512) at /exec.c:3177
#7 address_space_write (as=0x557fd54e7a00 <address_space_memory>, addr=136728041144064, attrs=..., buf=0x7fff1fc0d660, len=512) at /exec.c:3271
#8 dma_memory_set (as=0x557fd54e7a00 <address_space_memory>, addr=136728041144064, c=0 '\000', len=1378422272) at /dma-helpers.c:31
#9 fw_cfg_dma_transfer (s=0x61a000001e80) at /hw/nvram/fw_cfg.c:400
#10 fw_cfg_dma_mem_write (opaque=0x61a000001e80, addr=4, value=4294940309, size=4) at /hw/nvram/fw_cfg.c:467
#11 memory_region_write_accessor (mr=0x61a000002200, addr=4, value=0x7fff1fc0e3d0, size=4, shift=0, mask=4294967295, attrs=...) at /memory.c:483
#12 access_with_adjusted_size (addr=4, value=0x7fff1fc0e3d0, size=4, access_size_min=1, access_size_max=8, access_fn=0x557fd2288c80 <memory_region_write_accessor>, mr=0x61a000002200, attrs=...)
pment/qemu/memory.c:539
#13 memory_region_dispatch_write (mr=0x61a000002200, addr=4, data=4294940309, op=MO_32, attrs=...) at /memory.c:1476
#14 flatview_write_continue (fv=0x606000035f00, addr=1304, attrs=..., ptr=0x7fff1fc0ec40, len=4, addr1=4, l=4, mr=0x61a000002200) at /exec.c:3137
#15 flatview_write (fv=0x606000035f00, addr=1304, attrs=..., buf=0x7fff1fc0ec40, len=4) at /exec.c:3177
#16 address_space_write (as=0x557fd54e7bc0 <address_space_io>, addr=1304, attrs=..., buf=0x7fff1fc0ec40, len=4) at /exec.c:3271
It looks like fw_cfg_dma_transfer gets the address(136728041144064) and length(1378422272) for the read from the value provided as input 4294940309 (0xFFFF9695) which lands in pcbios. Should there be any limits on the length of guest-memory that fw_cfg should populate?
Found by libfuzzer
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prev parent reply other threads:[~2021-06-15 18:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 4:12 [Bug 1880355] [NEW] Length restrictions for fw_cfg_dma_transfer? Alexander Bulekov
2020-05-24 10:30 ` Philippe Mathieu-Daudé
2020-05-24 10:30 ` Philippe Mathieu-Daudé
2020-05-24 13:40 ` Peter Maydell
2020-05-24 13:40 ` Peter Maydell
2020-05-24 14:27 ` Philippe Mathieu-Daudé
2020-05-24 14:27 ` Philippe Mathieu-Daudé
2020-05-25 13:59 ` Paolo Bonzini
2020-05-25 9:14 ` Mark Cave-Ayland
2020-05-25 9:14 ` Mark Cave-Ayland
2021-06-10 15:50 ` [Bug 1880355] " Thomas Huth
2021-06-14 23:35 ` Alexander Bulekov
2021-06-15 18:17 ` Thomas Huth [this message]
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