On Wed, 26 Oct 2016, Stefano Stabellini wrote: > On Wed, 26 Oct 2016, Wei Liu wrote: > > On Wed, Oct 26, 2016 at 05:09:52PM +0200, Igor Mammedov wrote: > > > On Tue, 25 Oct 2016 18:28:04 +0100 > > > Wei Liu <wei.l...@citrix.com> wrote: > > > > > > > Xen's toolstack is in charge of building ACPI tables. Skip acpi table > > > > building if running on Xen. > > > > > > > > This issue is discovered due to direct kernel boot on Xen doesn't boot > > > > anymore, because the new ACPI tables cause the guest to exceed its > > > > memory allocation limit. > > > > > > > > Reported-by: Sander Eikelenboom <li...@eikelenboom.it> > > > > Signed-off-by: Wei Liu <wei.l...@citrix.com> > > > Question is: > > > Why does xen guest get ACPI tables from QEMU instead of using > > > Xen provided ones. > > > Maybe it's firmware issue i.e. firmware side shouldn't load > > > ACPI tables from QEMU provided fwcfg file and load Xen provided instead. > > > > > > > It hasn't come to the point that the guest is booted. QEMU exits when > > trying to populate some pages for the guest, at which point the guest > > has not yet been started. In a sense, Xen guest doesn't get ACPI from > > QEMU because it never gets to that point. > > > > Direct kernel boot causes fw_cfg to be filled in. pcms->has_acpi_build > > defaults to true and acpi_enabled is also true. These make all checks in > > acpi_setup pass. QEMU proceeds to build and load ACPI tables (which are > > never going to be used by Xen guests), causing the guest to exceeds its > > limit. > > What if libxl passes -no-acpi to QEMU?
Of course even if that works, I think we should still fix this properly in QEMU > > > > --- > > > > Cc: Anthony PERARD <anthony.per...@citrix.com> > > > > Cc: Stefano Stabellini <sstabell...@kernel.org> > > > > > > > > RFC because I'm not sure this is the best way to fix it. > > > > --- > > > > hw/i386/acpi-build.c | 6 ++++++ > > > > 1 file changed, 6 insertions(+) > > > > > > > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c > > > > index a26a4bb..2cdff12 100644 > > > > --- a/hw/i386/acpi-build.c > > > > +++ b/hw/i386/acpi-build.c > > > > @@ -45,6 +45,7 @@ > > > > #include "sysemu/tpm_backend.h" > > > > #include "hw/timer/mc146818rtc_regs.h" > > > > #include "sysemu/numa.h" > > > > +#include "hw/xen/xen.h" > > > > > > > > /* Supported chipsets: */ > > > > #include "hw/acpi/piix4.h" > > > > @@ -2865,6 +2866,11 @@ void acpi_setup(void) > > > > return; > > > > } > > > > > > > > + if (xen_enabled()) { > > > > + ACPI_BUILD_DPRINTF("Xen enabled. Bailing out.\n"); > > > > + return; > > > > + } > > > > + > > > > build_state = g_malloc0(sizeof *build_state); > > > > > > > > acpi_set_pci_info(); > > > > > > _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel