From: "Liu, Yi L" <yi.l.liu@intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: "mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>, "jasowang@redhat.com" <jasowang@redhat.com>, "Hao, Xudong" <xudong.hao@intel.com>, "Duan, Zhenzhong" <zhenzhong.duan@intel.com>, "peterx@redhat.com" <peterx@redhat.com>, "Xu, Terrence" <terrence.xu@intel.com>, "chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>, "linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "lulu@redhat.com" <lulu@redhat.com>, "Jiang, Yanting" <yanting.jiang@intel.com>, "joro@8bytes.org" <joro@8bytes.org>, "nicolinc@nvidia.com" <nicolinc@nvidia.com>, "Tian, Kevin" <kevin.tian@intel.com>, "Zhao, Yan Y" <yan.y.zhao@intel.com>, "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>, "eric.auger@redhat.com" <eric.auger@redhat.com>, "intel-gvt-dev@lists.freedesktop.org" <intel-gvt-dev@lists.freedesktop.org>, "yi.y.sun@linux.intel.com" <yi.y.sun@linux.intel.com>, "clegoate@redhat.com" <clegoate@redhat.com>, "cohuck@redhat.com" <cohuck@redhat.com>, "shameerali.kolothum.thodi@huawei.com" <shameerali.kolothum.thodi@huawei.com>, "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>, "robin.murphy@arm.com" <robin.murphy@arm.com> Subject: Re: [Intel-gfx] [PATCH v7 8/9] vfio/pci: Extend VFIO_DEVICE_GET_PCI_HOT_RESET_INFO for vfio device cdev Date: Thu, 15 Jun 2023 03:31:30 +0000 [thread overview] Message-ID: <DS0PR11MB7529F040A43594B6A8E79874C35BA@DS0PR11MB7529.namprd11.prod.outlook.com> (raw) In-Reply-To: <ZInCs7augGxSzWYp@nvidia.com> > From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Wednesday, June 14, 2023 9:38 PM > > On Wed, Jun 14, 2023 at 01:05:45PM +0000, Liu, Yi L wrote: > > > -EAGAIN basically means the kernel internally malfunctioned - eg it > > > allocated too little space for the actual size of devices. That is no > > > longer possible in this version so it should never return -EAGAIN. > > > > I still have one doubt. Per my understanding, this is to handle newly > > plugged devices during the info reporting path. I don’t think holding > > dev_set lock can prevent it. but maybe -ENOSPC is enough. @Alex, > > what about your opinion? > > If the device was plug instantly before we computed the size we returned > ENOSPC > > If it was plugged instantly after we computed the size we returned > EAGAIN Yes. > Here we just resolve this race consistently to always return ENOSPC, > which always means we ran out of space in the user provided buffer. This makes sense. > > > - kfree(devices); > > > - return ret; > > > + if (fill.count != fill.devices - arg->devices) > > > > Should be "if (fill.count != (fill.devices - arg->devices) / sizeof(arg->devices[0]))" 😊 > > devices is already a typed pointer so the compiler computes the > /sizeof() itself > > Your version above is needed if it was void * Got it. Regards, Yi Liu
WARNING: multiple messages have this Message-ID (diff)
From: "Liu, Yi L" <yi.l.liu@intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: "alex.williamson@redhat.com" <alex.williamson@redhat.com>, "Tian, Kevin" <kevin.tian@intel.com>, "joro@8bytes.org" <joro@8bytes.org>, "robin.murphy@arm.com" <robin.murphy@arm.com>, "cohuck@redhat.com" <cohuck@redhat.com>, "eric.auger@redhat.com" <eric.auger@redhat.com>, "nicolinc@nvidia.com" <nicolinc@nvidia.com>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>, "chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>, "yi.y.sun@linux.intel.com" <yi.y.sun@linux.intel.com>, "peterx@redhat.com" <peterx@redhat.com>, "jasowang@redhat.com" <jasowang@redhat.com>, "shameerali.kolothum.thodi@huawei.com" <shameerali.kolothum.thodi@huawei.com>, "lulu@redhat.com" <lulu@redhat.com>, "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>, "intel-gvt-dev@lists.freedesktop.org" <intel-gvt-dev@lists.freedesktop.org>, "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>, "linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>, "Hao, Xudong" <xudong.hao@intel.com>, "Zhao, Yan Y" <yan.y.zhao@intel.com>, "Xu, Terrence" <terrence.xu@intel.com>, "Jiang, Yanting" <yanting.jiang@intel.com>, "Duan, Zhenzhong" <zhenzhong.duan@intel.com>, "clegoate@redhat.com" <clegoate@redhat.com> Subject: RE: [PATCH v7 8/9] vfio/pci: Extend VFIO_DEVICE_GET_PCI_HOT_RESET_INFO for vfio device cdev Date: Thu, 15 Jun 2023 03:31:30 +0000 [thread overview] Message-ID: <DS0PR11MB7529F040A43594B6A8E79874C35BA@DS0PR11MB7529.namprd11.prod.outlook.com> (raw) In-Reply-To: <ZInCs7augGxSzWYp@nvidia.com> > From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Wednesday, June 14, 2023 9:38 PM > > On Wed, Jun 14, 2023 at 01:05:45PM +0000, Liu, Yi L wrote: > > > -EAGAIN basically means the kernel internally malfunctioned - eg it > > > allocated too little space for the actual size of devices. That is no > > > longer possible in this version so it should never return -EAGAIN. > > > > I still have one doubt. Per my understanding, this is to handle newly > > plugged devices during the info reporting path. I don’t think holding > > dev_set lock can prevent it. but maybe -ENOSPC is enough. @Alex, > > what about your opinion? > > If the device was plug instantly before we computed the size we returned > ENOSPC > > If it was plugged instantly after we computed the size we returned > EAGAIN Yes. > Here we just resolve this race consistently to always return ENOSPC, > which always means we ran out of space in the user provided buffer. This makes sense. > > > - kfree(devices); > > > - return ret; > > > + if (fill.count != fill.devices - arg->devices) > > > > Should be "if (fill.count != (fill.devices - arg->devices) / sizeof(arg->devices[0]))" 😊 > > devices is already a typed pointer so the compiler computes the > /sizeof() itself > > Your version above is needed if it was void * Got it. Regards, Yi Liu
next prev parent reply other threads:[~2023-06-15 3:31 UTC|newest] Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-02 12:15 [PATCH v7 0/9] Enhance vfio PCI hot reset for vfio cdev device Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-02 12:15 ` [PATCH v7 1/9] vfio/pci: Update comment around group_fd get in vfio_pci_ioctl_pci_hot_reset() Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-02 12:15 ` [PATCH v7 2/9] vfio/pci: Move the existing hot reset logic to be a helper Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-02 12:15 ` [PATCH v7 3/9] iommufd: Reserve all negative IDs in the iommufd xarray Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-13 11:46 ` Jason Gunthorpe 2023-06-13 11:46 ` [Intel-gfx] " Jason Gunthorpe 2023-06-02 12:15 ` [PATCH v7 4/9] iommufd: Add iommufd_ctx_has_group() Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-08 21:40 ` Alex Williamson 2023-06-08 21:40 ` Alex Williamson 2023-06-08 23:44 ` Liu, Yi L 2023-06-08 23:44 ` [Intel-gfx] " Liu, Yi L 2023-06-13 11:46 ` Jason Gunthorpe 2023-06-13 11:46 ` [Intel-gfx] " Jason Gunthorpe 2023-06-02 12:15 ` [PATCH v7 5/9] iommufd: Add helper to retrieve iommufd_ctx and devid Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-13 11:47 ` Jason Gunthorpe 2023-06-13 11:47 ` [Intel-gfx] " Jason Gunthorpe 2023-06-02 12:15 ` [PATCH v7 6/9] vfio: Mark cdev usage in vfio_device Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-13 17:56 ` Jason Gunthorpe 2023-06-13 17:56 ` [Intel-gfx] " Jason Gunthorpe 2023-06-14 5:56 ` Liu, Yi L 2023-06-14 5:56 ` [Intel-gfx] " Liu, Yi L 2023-06-14 12:11 ` Jason Gunthorpe 2023-06-14 12:11 ` [Intel-gfx] " Jason Gunthorpe 2023-06-02 12:15 ` [PATCH v7 7/9] vfio: Add helper to search vfio_device in a dev_set Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-13 11:47 ` Jason Gunthorpe 2023-06-13 11:47 ` Jason Gunthorpe 2023-06-02 12:15 ` [PATCH v7 8/9] vfio/pci: Extend VFIO_DEVICE_GET_PCI_HOT_RESET_INFO for vfio device cdev Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-08 22:26 ` Alex Williamson 2023-06-08 22:26 ` Alex Williamson 2023-06-09 0:04 ` Liu, Yi L 2023-06-09 0:04 ` [Intel-gfx] " Liu, Yi L 2023-06-13 11:46 ` Jason Gunthorpe 2023-06-13 11:46 ` [Intel-gfx] " Jason Gunthorpe 2023-06-13 12:50 ` Liu, Yi L 2023-06-13 12:50 ` [Intel-gfx] " Liu, Yi L 2023-06-13 14:32 ` Alex Williamson 2023-06-13 14:32 ` Alex Williamson 2023-06-13 17:40 ` Jason Gunthorpe 2023-06-13 17:40 ` [Intel-gfx] " Jason Gunthorpe 2023-06-13 18:23 ` Jason Gunthorpe 2023-06-13 18:23 ` [Intel-gfx] " Jason Gunthorpe 2023-06-14 10:35 ` Liu, Yi L 2023-06-14 10:35 ` [Intel-gfx] " Liu, Yi L 2023-06-14 12:17 ` Jason Gunthorpe 2023-06-14 12:17 ` [Intel-gfx] " Jason Gunthorpe 2023-06-14 13:05 ` Liu, Yi L 2023-06-14 13:05 ` [Intel-gfx] " Liu, Yi L 2023-06-14 13:37 ` Jason Gunthorpe 2023-06-14 13:37 ` [Intel-gfx] " Jason Gunthorpe 2023-06-15 3:31 ` Liu, Yi L [this message] 2023-06-15 3:31 ` Liu, Yi L 2023-06-02 12:15 ` [PATCH v7 9/9] vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET Yi Liu 2023-06-02 12:15 ` [Intel-gfx] " Yi Liu 2023-06-08 22:30 ` Alex Williamson 2023-06-08 22:30 ` Alex Williamson 2023-06-09 0:13 ` Liu, Yi L 2023-06-09 0:13 ` [Intel-gfx] " Liu, Yi L 2023-06-09 14:38 ` Jason Gunthorpe 2023-06-09 14:38 ` [Intel-gfx] " Jason Gunthorpe 2023-06-13 18:09 ` Jason Gunthorpe 2023-06-13 18:09 ` [Intel-gfx] " Jason Gunthorpe 2023-06-02 15:14 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for Enhance vfio PCI hot reset for vfio cdev device (rev5) Patchwork 2023-06-02 15:29 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork 2023-06-04 20:05 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork 2023-06-08 6:59 ` [PATCH v7 0/9] Enhance vfio PCI hot reset for vfio cdev device Jiang, Yanting 2023-06-08 6:59 ` [Intel-gfx] " Jiang, Yanting 2023-06-13 20:47 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Enhance vfio PCI hot reset for vfio cdev device (rev6) Patchwork 2023-06-14 15:47 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Enhance vfio PCI hot reset for vfio cdev device (rev7) Patchwork
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