On Wed, Jan 22, 2020 at 04:54:55PM +0800, Weihang Li wrote: > > > On 2020/1/17 3:51, Jason Gunthorpe wrote: > >>> What happens to your userspace if it runs on an old kernel and tries > >>> to use extended atomic? > >>> > >>> Jason > >>> > >> Hi Jason, > >> > >> If the hns userspace runs with old kernel, the hardware will report a asynchronous > >> event for the extended atomic operation and modify the qp to error state because > >> the enable bit in this qp's context hasn't been set. > >> > >> The driver will print like this: > >> > >> [ 1252.240921] hns3 0000:7d:00.0: Invalid request local work queue 0x9 error. > >> [ 1252.247772] hns3 0000:7d:00.0: no hr_qp can be found! > > Ideally the provider will not set > > IBV_PCI_ATOMIC_OPERATION_4_BYTE_SIZE_SUP and related without kernel > > support.. > > > > I've applied this patch, but I feel like you may need a followup to > > fix the capability reporting? > > > > Jason > > Hi Jason, > > Thank for your suggestions. > > But I'm confuse about the relationship between "PCI ATOMIC" in this macro > and atomic operations in RDMA. > > I found the related series on patchwork: > https://patchwork.kernel.org/cover/10782873/ I may have got the wrong capability bit here, I'm not sure where the capability bits for extended atomics are actually Jason
