On Wed, Oct 12, 2022 at 10:55:57AM -0400, Steven Sistare wrote: > On 10/12/2022 10:40 AM, Jason Gunthorpe wrote: > > On Wed, Oct 12, 2022 at 09:50:53AM -0400, Steven Sistare wrote: > > > >>> Anyhow, I think this conversation has convinced me there is no way to > >>> fix VFIO_DMA_UNMAP_FLAG_VADDR. I'll send a patch reverting it due to > >>> it being a security bug, basically. > >> > >> Please do not. Please give me the courtesy of time to develop a replacement > >> before we delete it. Surely you can make progress on other opens areas of iommufd > >> without needing to delete this immediately. > > > > I'm not worried about iommufd, I'm worried about shipping kernels with > > a significant security problem backed into them. > > > > As we cannot salvage this interface it should quickly deleted so that > > it doesn't cause any incidents. > > > > It will not effect your ability to create a replacement. > > I am not convinced we cannot salvage the interface, and indeed I might want to reuse > parts of it, and you are over-stating the risk of a feature that is already in > millions of kernels and has been for years. Deleting it all before having a > replacement hurts the people like myself who are continuing to develop and test > live update in qemu on the latest kernels. I think this is a mistake, as I'm convinced it cannot be salvaged, but we could instead guard it by a config symbol and CONFIG_EXPERIMENTAL. Jason
