On Thu, 25 Jul 2019 13:38:48 -0400 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Thu, Jul 25, 2019 at 05:39:39PM +0200, Paolo Bonzini wrote: > > On 25/07/19 17:01, Michael S. Tsirkin wrote: > > >> It would be educational to try to enable ACPI core but disable all > > >> optional features. > > > > A lot of them are select'ed so it's not easy. > > > > > Trying with ACPI_REDUCED_HARDWARE_ONLY would also be educational. > > > > That's what the NEMU guys experimented with. It's not supported by our > > DSDT since it uses ACPI GPE, > > Well there are two GPE blocks in FADT. We could just switch to > these if necesary I think. if it's simplistic vm we could build dedicated DSDT (or whole set of tables) for it and use reduced profile like arm-virt machine does (just a newer version of FADT with need flags set). That probably would cut acpi cost on QEMU side. > > and the reduction in code size is small > > (about 15000 lines of code in ACPICA, perhaps 100k if you're lucky?). > > > > Paolo > > Well ACPI is 150k loc I think, right? > > linux]$ wc -l `find drivers/acpi/ -name '*.c' `|tail -1 > 145926 total > > So 100k wouldn't be too shabby. >