From: Alex Williamson <alex.williamson@redhat.com>
To: Zenghui Yu <yuzenghui@huawei.com>
Cc: cohuck@redhat.com, cjia@nvidia.com, aik@ozlabs.ru,
Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com,
qemu-devel@nongnu.org, peterx@redhat.com,
Kirti Wankhede <kwankhede@nvidia.com>,
eauger@redhat.com, yi.l.liu@intel.com, eskultet@redhat.com,
ziye.yang@intel.com, armbru@redhat.com, mlevitsk@redhat.com,
pasic@linux.ibm.com, felipe@nutanix.com,
wanghaibin.wang@huawei.com, zhi.a.wang@intel.com,
kevin.tian@intel.com, yan.y.zhao@intel.com, dgilbert@redhat.com,
changpeng.liu@intel.com, quintela@redhat.com,
lushenming@huawei.com, Ken.Xue@amd.com,
jonathan.davies@nutanix.com, pbonzini@redhat.com
Subject: Re: [PATCH v26 03/17] vfio: Add save and load functions for VFIO PCI devices
Date: Wed, 21 Oct 2020 13:03:57 -0600 [thread overview]
Message-ID: <20201021130357.7eab9f3e@w520.home> (raw)
In-Reply-To: <c37eebe4-45d1-ea55-0540-3a2aecea442b@huawei.com>
On Wed, 21 Oct 2020 17:30:04 +0800
Zenghui Yu <yuzenghui@huawei.com> wrote:
> On 2020/9/25 6:49, Alex Williamson wrote:
> >> + } else if (interrupt_type == VFIO_INT_MSIX) {
> >> + uint16_t offset;
> >> +
> >> + msix_load(pdev, f);
> >> + offset = pci_default_read_config(pdev,
> >> + pdev->msix_cap + PCI_MSIX_FLAGS + 1, 2);
> >> + /* load enable bit and maskall bit */
> >> + vfio_pci_write_config(pdev, pdev->msix_cap + PCI_MSIX_FLAGS + 1,
> >> + offset, 2);
>
> It isn't clear that what purpose this load operation serves. The config
> space has already been restored and we'll see that MSI-X _was_ and _is_
> enabled (or disabled). vfio_msix_enable() will therefore not be invoked
> and no vectors would actually be enabled... Not sure if I had missed
> something.
Yeah, afaict your interpretation is correct. I think the intention was
to mimic userspace preforming a write to set the enable bit, but
re-writing it doesn't change the vconfig value, so the effect is not
the same. I think this probably never worked.
> >> + }
> >> + return 0;
> >
> > It seems this could be simplified down to:
> >
> > if (msi_enabled(pdev)) {
> > vfio_msi_enable(vdev);
> > } else if (msix_enabled(pdev)) {
> > msix_load(pdev, f);
> > vfio_msix_enable(vdev);
> > }
>
> And it seems that this has fixed something :-)
Yep, no dependency on the value changing, simply set the state to that
indicated in vconfig. Thanks,
Alex
next prev parent reply other threads:[~2020-10-21 19:25 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 23:24 [PATCH QEMU v25 00/17] Add migration support for VFIO devices Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 01/17] vfio: Add function to unmap VFIO region Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 02/17] vfio: Add vfio_get_object callback to VFIODeviceOps Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 03/17] vfio: Add save and load functions for VFIO PCI devices Kirti Wankhede
2020-09-23 6:38 ` Zenghui Yu
2020-09-24 22:49 ` Alex Williamson
2020-10-21 9:30 ` Zenghui Yu
2020-10-21 19:03 ` Alex Williamson [this message]
2020-09-22 23:24 ` [PATCH v26 04/17] vfio: Add migration region initialization and finalize function Kirti Wankhede
2020-09-24 14:08 ` Cornelia Huck
2020-10-17 20:14 ` Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-09-28 9:39 ` Cornelia Huck
2020-10-17 20:17 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 05/17] vfio: Add VM state change handler to know state of VM Kirti Wankhede
2020-09-24 15:02 ` Cornelia Huck
2020-09-29 11:03 ` Dr. David Alan Gilbert
2020-10-17 20:24 ` Kirti Wankhede
2020-10-20 10:51 ` Cornelia Huck
2020-10-21 5:33 ` Kirti Wankhede
2020-10-22 7:51 ` Cornelia Huck
2020-10-22 15:42 ` Kirti Wankhede
2020-10-22 15:49 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:30 ` Kirti Wankhede
2020-10-17 23:44 ` Alex Williamson
2020-10-18 17:43 ` Kirti Wankhede
2020-10-19 17:51 ` Alex Williamson
2020-10-20 10:23 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 06/17] vfio: Add migration state change notifier Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:35 ` Kirti Wankhede
2020-10-19 17:57 ` Alex Williamson
2020-10-20 10:55 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 07/17] vfio: Register SaveVMHandlers for VFIO device Kirti Wankhede
2020-09-24 15:15 ` Philippe Mathieu-Daudé
2020-09-29 10:19 ` Dr. David Alan Gilbert
2020-10-17 20:36 ` Kirti Wankhede
2020-09-25 11:53 ` Cornelia Huck
2020-10-18 20:55 ` Kirti Wankhede
2020-10-20 15:51 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-18 17:40 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 08/17] vfio: Add save state functions to SaveVMHandlers Kirti Wankhede
2020-09-23 11:42 ` Wang, Zhi A
2020-10-21 14:30 ` Kirti Wankhede
2020-09-25 21:02 ` Alex Williamson
2020-10-18 18:00 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 09/17] vfio: Add load " Kirti Wankhede
2020-10-01 10:07 ` Cornelia Huck
2020-10-18 20:47 ` Kirti Wankhede
2020-10-20 16:25 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 10/17] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 11/17] vfio: Get migration capability flags for container Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 12/17] vfio: Add function to start and stop dirty pages tracking Kirti Wankhede
2020-09-25 21:55 ` Alex Williamson
2020-10-18 20:52 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 13/17] vfio: create mapped iova list when vIOMMU is enabled Kirti Wankhede
2020-09-25 22:23 ` Alex Williamson
2020-10-19 6:01 ` Kirti Wankhede
2020-10-19 17:24 ` Alex Williamson
2020-10-19 19:15 ` Kirti Wankhede
2020-10-19 20:07 ` Alex Williamson
2020-09-22 23:24 ` [PATCH v26 14/17] vfio: Add vfio_listener_log_sync to mark dirty pages Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 15/17] vfio: Add ioctl to get dirty pages bitmap during dma unmap Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 16/17] vfio: Make vfio-pci device migration capable Kirti Wankhede
2020-09-25 12:17 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 17/17] qapi: Add VFIO devices migration stats in Migration stats Kirti Wankhede
2020-09-24 15:14 ` Eric Blake
2020-09-25 22:55 ` Alex Williamson
2020-09-29 10:40 ` Dr. David Alan Gilbert
2020-09-23 7:06 ` [PATCH QEMU v25 00/17] Add migration support for VFIO devices Zenghui Yu
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