Re: [PULL 00/20] pc,virtio,pci: fixes, features

[Michael S. Tsirkin]

On Mon, Mar 22, 2021 at 06:46:06PM +0000, Peter Maydell wrote:
> On Mon, 22 Mar 2021 at 16:41, Peter Maydell <peter.maydell@linaro.org> wrote:
> >
> > On Mon, 22 Mar 2021 at 15:44, Michael S. Tsirkin <mst@redhat.com> wrote:
> > >
> > > The following changes since commit 
> > > f0f20022a0c744930935fdb7020a8c18347d391a:
> > >
> > >   Merge remote-tracking branch 
> > > 'remotes/thuth-gitlab/tags/pull-request-2021-03-21' into staging 
> > > (2021-03-22 10:05:45 +0000)
> > >
> > > are available in the Git repository at:
> > >
> > >   git://git.kernel.org/pub/scm/virt/kvm/mst/qemu.git tags/for_upstream
> > >
> > > for you to fetch changes up to 5971d4a968d51a80daaad53ddaec2b285115af62:
> > >
> > >   acpi: Move setters/getters of oem fields to X86MachineState (2021-03-22 
> > > 11:39:02 -0400)
> > >
> > > ----------------------------------------------------------------
> > > pc,virtio,pci: fixes, features
> > >
> > > Fixes all over the place.
> > > ACPI index support.
> > >
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > >
> >
> > This triggers a new clang runtime sanitizer warning:
> 
> With a backtrace:
> $ UBSAN_OPTIONS=print_stacktrace=1
> QTEST_QEMU_BINARY=build/clang/qemu-system-mips64el
> ./build/clang/tests/qtest/endianness-test -p
> /mips64el/endianness/fuloong2e
> /mips64el/endianness/fuloong2e: ../../hw/pci/pci.c:252:30: runtime
> error: shift exponent -1 is negative
>     #0 0x55a17bc17a1f in pci_irq_state
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/pci/pci.c:252:30
>     #1 0x55a17bc17a1f in pci_irq_handler
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/pci/pci.c:1453
>     #2 0x55a17b7ed0a5 in pm_update_sci
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/isa/vt82c686.c:147:5
>     #3 0x55a17b7ecce3 in via_pm_reset
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/isa/vt82c686.c:173:5
>     #4 0x55a17c546cc7 in resettable_phase_hold
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:182:13
>     #5 0x55a17c53839a in bus_reset_child_foreach
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/bus.c:97:13
>     #6 0x55a17c546bc2 in resettable_phase_hold
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:173:5
>     #7 0x55a17c5435ca in device_reset_child_foreach
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/qdev.c:366:9
>     #8 0x55a17c546bc2 in resettable_phase_hold
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:173:5
>     #9 0x55a17c53839a in bus_reset_child_foreach
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/bus.c:97:13
>     #10 0x55a17c546bc2 in resettable_phase_hold
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:173:5
>     #11 0x55a17c545ee0 in resettable_assert_reset
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:60:5
>     #12 0x55a17c545dbf in resettable_reset
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/resettable.c:45:5
>     #13 0x55a17c545d68 in qemu_devices_reset
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/reset.c:69:9
>     #14 0x55a17c47b3eb in qemu_system_reset
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../softmmu/runstate.c:444:9
>     #15 0x55a17ba225ee in qdev_machine_creation_done
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../hw/core/machine.c:1279:5
>     #16 0x55a17c4bdb03 in qemu_machine_creation_done
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../softmmu/vl.c:2567:5
>     #17 0x55a17c4bdb03 in qmp_x_exit_preconfig
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../softmmu/vl.c:2590
>     #18 0x55a17c4c2c0b in qemu_init
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../softmmu/vl.c:3611:9
>     #19 0x55a17b756db5 in main
> /home/petmay01/linaro/qemu-for-merges/build/clang/../../softmmu/main.c:49:5
>     #20 0x7f3a9c9f6bf6 in __libc_start_main
> /build/glibc-S9d2JN/glibc-2.27/csu/../csu/libc-start.c:310
>     #21 0x55a17b731969 in _start
> (/home/petmay01/linaro/qemu-for-merges/build/clang/qemu-system-mips64el+0x1140969)
> 
> OK
> 
> Suggests the relevant commit is
> "acpi:piix4, vt82c686: reinitialize acpi PM device on reset"

Yep, Cc'd the authors and dropped for now. Thanks!

> This happens because pm_update_sci() calls pci_irq_handler(),
> which calls pci_intx(pci_dev), which returns -1, which is not
> a valid interrupt number to call pci_irq_handler() with.
> 
> Q: given that pci_irq_handler() says it must only be called with
> an irqnum in [0..3], shouldn't pci_set_irq() be a bit more
> cautious than to pull a byte directly out of PCI_INTERRUPT_PIN
> and assume it's valid? (Is this guest-writable, or is it read-only?)

It's read-only.

> 
> thanks
> -- PMM


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