From: Peter Maydell <peter.maydell@linaro.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Dmitry Vyukov" <dvyukov@google.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Marc Zyngier" <maz@kernel.org>, "Will Deacon" <will@kernel.org>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
syzkaller <syzkaller@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>,
"John Garry" <john.garry@huawei.com>,
"Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: arm64 syzbot instances
Date: Sat, 20 Mar 2021 20:43:25 +0000 [thread overview]
Message-ID: <CAFEAcA-s79=4VDSA3TO8tpLUMwJE=HcFT4eZO8L8CCkAAfj8PA@mail.gmail.com> (raw)
In-Reply-To: <CAK8P3a2NEcHG+nOUCc6-DPeFKkc-GF-LEOkynhNdgxiXBHdQaw@mail.gmail.com>
On Fri, 12 Mar 2021 at 09:16, Arnd Bergmann <arnd@arndb.de> wrote:
> So it's probably qemu that triggers the 'synchronous external
> abort' when accessing the PCI I/O space, which in turn hints
> towards a bug in qemu. Presumably it only returns data from
> I/O ports that are actually mapped to a device when real hardware
> is supposed to return 0xffffffff when reading from unused I/O ports.
Do you have a reference to the bit of the PCI spec that mandates
this -1/discard behaviour for attempted access to places where
there isn't actually a PCI device mapped ? The spec is pretty
long and hard to read...
(Knowing to what extent this behaviour is mandatory for all
PCI systems/host controllers vs just "it would be nice if the
gpex host controller worked this way" would help in figuring
out where in QEMU to change.)
thanks
-- PMM
next prev parent reply other threads:[~2021-03-20 20:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-11 11:38 arm64 syzbot instances Dmitry Vyukov
2021-03-11 12:33 ` Mark Rutland
2021-03-11 16:56 ` Dmitry Vyukov
2021-03-17 18:45 ` Mark Rutland
2021-03-18 8:32 ` Dmitry Vyukov
2021-03-11 17:11 ` Dmitry Vyukov
2021-03-11 13:30 ` Arnd Bergmann
2021-03-11 17:25 ` Dmitry Vyukov
2021-03-12 6:42 ` Dmitry Vyukov
2021-03-11 17:57 ` Dmitry Vyukov
2021-03-12 8:39 ` Arnd Bergmann
2021-03-12 8:46 ` Dmitry Vyukov
2021-03-12 9:16 ` Arnd Bergmann
2021-03-12 9:21 ` Dmitry Vyukov
2021-03-12 10:10 ` Arnd Bergmann
2021-03-12 10:38 ` Dmitry Vyukov
2021-03-12 10:52 ` Arnd Bergmann
2021-03-15 9:43 ` John Garry
2021-03-15 10:01 ` Dmitry Vyukov
2021-03-15 10:29 ` John Garry
2021-03-15 10:34 ` Dmitry Vyukov
2021-03-15 11:11 ` Arnd Bergmann
2021-03-20 20:43 ` Peter Maydell [this message]
2021-03-21 11:52 ` Arnd Bergmann
2021-03-21 11:55 ` Arnd Bergmann
2021-03-21 18:59 ` Arnd Bergmann
2021-03-22 13:51 ` Peter Maydell
2021-03-22 15:42 ` Arnd Bergmann
2021-03-22 16:34 ` John Garry
2021-03-22 16:49 ` Peter Maydell
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