----- Original Message ----- > From: "Michael S. Tsirkin" <m...@redhat.com> > To: "Paolo Bonzini" <pbonz...@redhat.com> > Cc: seab...@seabios.org, "Kevin O'Connor" <ke...@koconnor.net>, > qemu-devel@nongnu.org, ler...@redhat.com, > li...@philjordan.eu, imamm...@redhat.com, p...@philjordan.eu, > programmingk...@gmail.com, kra...@redhat.com > Sent: Wednesday, July 26, 2017 10:05:03 PM > Subject: Re: [seabios PATCH 1/2] seabios: build RSDT from XSDT > > On Wed, Jul 26, 2017 at 11:42:34AM +0200, Paolo Bonzini wrote: > > Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but > > new operating systems would like to have rev3 (ACPI 2.0). > > > > Since old operating systems do not know about XSDTs, the > > solution is to point the RSDT to a rev1 FADT and the XSDT to a > > rev3 FADT. > > > > But, edk2 is not able to handle QEMU providing two FADTs and barfs when > > it sees the second; edk2 subscribes to the view that the platform code > > (meaning not only OVMF, but transitively QEMU's ACPI table builder) > > should not handle such hacks; it's common edk2 code that should handle > > FADT rev1 vs. rev3 and RSDT vs. XSDT. > > What exactly does it do wrt RSDT?
It ignores the one produced by QEMU and builds it from scratch. Same for RSDP and XSDT. Paolo
