From: Max Reitz <mreitz@redhat.com>
To: Alex Williamson <alex.williamson@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>
Cc: "Artem Polyakov" <artemp@nvidia.com>,
"Zhengui li" <lizhengui@huawei.com>,
"Yan Zhao" <yan.y.zhao@intel.com>,
"Zhi Wang" <zhi.wang.linux@gmail.com>,
"Pierre Morel" <pmorel@linux.ibm.com>,
"Cornelia Huck" <cohuck@redhat.com>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Shameer Kolothum" <shameerali.kolothum.thodi@huawei.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Eric Auger" <eric.auger@redhat.com>,
"Kirti Wankhede" <kwankhede@nvidia.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Neo Jia" <cjia@nvidia.com>,
"Amey Narkhede" <ameynarkhede03@gmail.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Matthew Rosato" <mjrosato@linux.ibm.com>
Subject: Re: [PULL 00/32] VFIO updates 2020-10-26 (for QEMU 5.2 soft-freeze)
Date: Wed, 28 Oct 2020 10:21:03 +0100 [thread overview]
Message-ID: <b0423647-a03a-f601-bb16-2f161b3324ac@redhat.com> (raw)
In-Reply-To: <20201027200021.00fac851@x1.home>
On 28.10.20 03:00, Alex Williamson wrote:
> On Tue, 27 Oct 2020 23:42:57 +0000
> Peter Maydell <peter.maydell@linaro.org> wrote:
>
>> On Mon, 26 Oct 2020 at 19:39, Alex Williamson
>> <alex.williamson@redhat.com> wrote:
>>> ----------------------------------------------------------------
>>> VFIO update 2020-10-26
>>>
>>> * Migration support (Kirti Wankhede)
>>> * s390 DMA limiting (Matthew Rosato)
>>> * zPCI hardware info (Matthew Rosato)
>>> * Lock guard (Amey Narkhede)
>>> * Print fixes (Zhengui li)
>>
>> I get a conflict here in
>> include/standard-headers/linux/fuse.h:
>>
>> ++<<<<<<< HEAD
>> +#define FUSE_ATTR_FLAGS (1 << 27)
>> ++=======
>> + #define FUSE_SUBMOUNTS (1 << 27)
>> ++>>>>>>> remotes/awilliam/tags/vfio-update-20201026.0
Oh no.
>> I assume these should not both be trying to use the same value,
>> so something has gone wrong somewhere. The conflicting commit
>> now in master is Max's 97d741cc96dd08 ("linux/fuse.h: Pull in from Linux").
>>
>> Can you sort out the correct resolution between you, please?
>> (My guess is that Max's commit is the erroneous one because
>> it doesn't look like it was created via a standard update
>> from the kernel headers.)
It is the erroneous one, because it was based on an earlier version of
the kernel series.
> So as near as I can tell, QEMU commit 97d741cc96dd ("linux/fuse.h: Pull
> in from Linux") is fantasy land. The only thing I can find of this
> FUSE_ATTR_FLAGS outside Max's QEMU series is this[1] posting where the
> fuse maintainer announces that he's replaced FUSE_ATTR_FLAGS with
> FUSE_SUBMOUNTS, but the usage is "slightly different". Reading that
> thread, it seems that virtiofsd probably needed an update but I can't
> see that it ever happened.
No, it didn't happen yet. The series should have got a v2.
As an alternative to reverting, I could try to fix it up on top, but I
don't think that's really preferable. So I would vote for reverting.
> I'm not comfortable trying to update Max's series to try to determine
> if FUSE_SUBMOUNTS can be interchanged with FUSE_ATTR_FLAGS, where the
> latter appears to be used to express the new field in struct fuse_attr
> exists, but the former appears to be a feature. My guess would be that
> maybe FUSE_KERNEL_MINOR_VERSION needs to be tested instead for this new
> field??
It can't be interchanged 1:1. The series should be updated, but not
with such a hack as using some other indicator to see whether the flag
is there, but with properly using FUSE_SUBMOUNTS.
(I suppose technically it's OK for the virtiofsd side to interpret
FUSE_SUBMOUNTS as meaning the field to be present, because
FUSE_SUBMOUNTS does imply that. But I wouldn't want to test that
hypothesis, and instead just write a clean v2.)
> Anyway, I hate to pull the big hammer, but I think Max's series is
> bogus. The only thing I can propose is to revert it in its entirety,
> after which this series applies cleanly. I'll post a patch to do that
> as I think the code currently in master is on pretty shaky ground with
> respect to interpreting flag bits differently from those the kernel
> defines.
Sounds, well, not good, but definitely reasonable.
Thanks!
Max
next prev parent reply other threads:[~2020-10-28 9:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 19:32 [PULL 00/32] VFIO updates 2020-10-26 (for QEMU 5.2 soft-freeze) Alex Williamson
2020-10-26 19:32 ` [PULL 01/32] vfio: Add function to unmap VFIO region Alex Williamson
2020-10-26 19:32 ` [PULL 02/32] vfio: Add vfio_get_object callback to VFIODeviceOps Alex Williamson
2020-10-26 19:32 ` [PULL 03/32] vfio: Add save and load functions for VFIO PCI devices Alex Williamson
2020-10-26 19:32 ` [PULL 04/32] vfio: Add migration region initialization and finalize function Alex Williamson
2020-10-26 19:33 ` [PULL 05/32] vfio: Add VM state change handler to know state of VM Alex Williamson
2020-10-26 19:33 ` [PULL 06/32] vfio: Add migration state change notifier Alex Williamson
2020-10-26 19:33 ` [PULL 07/32] vfio: Register SaveVMHandlers for VFIO device Alex Williamson
2020-10-26 19:33 ` [PULL 08/32] vfio: Add save state functions to SaveVMHandlers Alex Williamson
2020-10-26 19:33 ` [PULL 09/32] vfio: Add load " Alex Williamson
2020-10-26 19:33 ` [PULL 10/32] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Alex Williamson
2020-10-26 19:34 ` [PULL 11/32] vfio: Get migration capability flags for container Alex Williamson
2020-10-26 19:34 ` [PULL 12/32] vfio: Add function to start and stop dirty pages tracking Alex Williamson
2020-10-26 19:34 ` [PULL 13/32] vfio: Add vfio_listener_log_sync to mark dirty pages Alex Williamson
2020-10-26 19:34 ` [PULL 14/32] vfio: Dirty page tracking when vIOMMU is enabled Alex Williamson
2020-10-26 19:34 ` [PULL 15/32] vfio: Add ioctl to get dirty pages bitmap during dma unmap Alex Williamson
2020-10-26 19:34 ` [PULL 16/32] vfio: Make vfio-pci device migration capable Alex Williamson
2020-10-26 19:34 ` [PULL 17/32] qapi: Add VFIO devices migration stats in Migration stats Alex Williamson
2020-10-26 19:35 ` [PULL 18/32] update-linux-headers: Add vfio_zdev.h Alex Williamson
2020-10-26 19:35 ` [PULL 19/32] linux-headers: update against 5.10-rc1 Alex Williamson
2020-10-26 19:35 ` [PULL 20/32] s390x/pci: Move header files to include/hw/s390x Alex Williamson
2020-10-26 19:35 ` [PULL 21/32] vfio: Create shared routine for scanning info capabilities Alex Williamson
2020-10-26 19:35 ` [PULL 22/32] vfio: Find DMA available capability Alex Williamson
2020-10-26 19:35 ` [PULL 23/32] s390x/pci: Add routine to get the vfio dma available count Alex Williamson
2020-10-26 19:35 ` [PULL 24/32] s390x/pci: Honor DMA limits set by vfio Alex Williamson
2020-10-26 19:35 ` [PULL 25/32] s390x/pci: create a header dedicated to PCI CLP Alex Williamson
2020-10-26 19:36 ` [PULL 26/32] s390x/pci: use a PCI Group structure Alex Williamson
2020-10-26 19:36 ` [PULL 27/32] s390x/pci: clean up s390 PCI groups Alex Williamson
2020-10-26 19:36 ` [PULL 28/32] s390x/pci: use a PCI Function structure Alex Williamson
2020-10-26 19:36 ` [PULL 29/32] vfio: Add routine for finding VFIO_DEVICE_GET_INFO capabilities Alex Williamson
2020-10-26 19:36 ` [PULL 30/32] s390x/pci: get zPCI function info from host Alex Williamson
2020-10-26 19:36 ` [PULL 31/32] hw/vfio: Use lock guard macros Alex Williamson
2020-10-26 19:36 ` [PULL 32/32] vfio: fix incorrect print type Alex Williamson
2020-10-27 23:42 ` [PULL 00/32] VFIO updates 2020-10-26 (for QEMU 5.2 soft-freeze) Peter Maydell
2020-10-28 2:00 ` Alex Williamson
2020-10-28 9:18 ` Dr. David Alan Gilbert
2020-10-28 15:23 ` Miklos Szeredi
2020-10-28 9:21 ` Max Reitz [this message]
2020-10-28 8:11 ` Cornelia Huck
2020-10-28 9:28 ` Max Reitz
2020-10-28 9:41 ` Max Reitz
2020-10-28 10:12 ` Cornelia Huck
2020-10-28 15:07 ` Peter Maydell
2020-10-28 15:20 ` Matthew Rosato
2020-10-28 15:41 ` Alex Williamson
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