[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v6 10/10] xen/arm: smmuv3: Add support for SMMUv3 driver
Hello Julien, > On 23 Jan 2021, at 11:55 am, Julien Grall <julien@xxxxxxx> wrote: > > Hi Rahul > > On 22/01/2021 11:37, Rahul Singh wrote: >> Add support for ARM architected SMMUv3 implementation. It is based on >> the Linux SMMUv3 driver. >> Driver is currently supported as Tech Preview. >> Major differences with regard to Linux driver are as follows: >> 2. Only Stage-2 translation is supported as compared to the Linux driver >> that supports both Stage-1 and Stage-2 translations. >> 3. Use P2M page table instead of creating one as SMMUv3 has the >> capability to share the page tables with the CPU. >> 4. Tasklets are used in place of threaded IRQ's in Linux for event queue >> and priority queue IRQ handling. >> 5. Latest version of the Linux SMMUv3 code implements the commands queue >> access functions based on atomic operations implemented in Linux. >> Atomic functions used by the commands queue access functions are not >> implemented in XEN therefore we decided to port the earlier version >> of the code. Atomic operations are introduced to fix the bottleneck >> of the SMMU command queue insertion operation. A new algorithm for >> inserting commands into the queue is introduced, which is lock-free >> on the fast-path. >> Consequence of reverting the patch is that the command queue >> insertion will be slow for large systems as spinlock will be used to >> serializes accesses from all CPUs to the single queue supported by >> the hardware. Once the proper atomic operations will be available in >> XEN the driver can be updated. >> 6. Spin lock is used in place of mutex when attaching a device to the >> SMMU, as there is no blocking locks implementation available in XEN. >> This might introduce latency in XEN. Need to investigate before >> driver is out for tech preview. >> 7. PCI ATS functionality is not supported, as there is no support >> available in XEN to test the functionality. Code is not tested and >> compiled. Code is guarded by the flag CONFIG_PCI_ATS. >> 8. MSI interrupts are not supported as there is no support available in >> XEN to request MSI interrupts. Code is not tested and compiled. Code >> is guarded by the flag CONFIG_MSI. >> Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx> >> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> > > Thank you for sending a new version. I have commited the series now. > Thank you for committing the series. Regards, Rahul > Cheers, > > -- > Julien Grall
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |