On Tue, Dec 10, 2019 at 02:07:36PM +1100, Alexey Kardashevskiy wrote: > > > On 07/12/2019 12:12, Ram Pai wrote: > > H_PUT_TCE_INDIRECT hcall uses a page filled with TCE entries, as one of > > its parameters. On secure VMs, hypervisor cannot access the contents of > > this page since it gets encrypted. Hence share the page with the > > hypervisor, and unshare when done. > > > I thought the idea was to use H_PUT_TCE and avoid sharing any extra > pages. There is small problem that when DDW is enabled, > FW_FEATURE_MULTITCE is ignored (easy to fix); I also noticed complains > about the performance on slack but this is caused by initial cleanup of > the default TCE window (which we do not use anyway) and to battle this > we can simply reduce its size by adding
something that takes hardly any time with H_PUT_TCE_INDIRECT, takes 13secs per device for H_PUT_TCE approach, during boot. This is with a 30GB guest. With larger guest, the time will further detoriate. > > -global > spapr-pci-host-bridge.dma_win_size=0x4000000 This option, speeds it up tremendously. But than should this option be enabled in qemu by default? only for secure VMs? for both VMs? RP
