| Message ID | 20161020185148.GJ5057@thinpad.lan.raisama.net |
|---|---|
| State | New |
| Headers | show |
On Thu, 20 Oct 2016 16:51:48 -0200 Eduardo Habkost <ehabkost@redhat.com> wrote: > On Thu, Oct 20, 2016 at 04:58:42PM +0200, Igor Mammedov wrote: > > Currently firmware uses 1 byte at 0x5F offset in RTC CMOS > > to get number of CPUs present at boot. However 1 byte is > > not enough to handle more than 255 CPUs. So add a new > > fw_cfg file that would allow QEMU to tell it. > > For compat reasons add file only for machine types that > > support more than 255 CPUs. > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com> > > I suggest squashing this into the patch, to clarify why we are > setting it to 0. > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Could you squash it in while merging series? > --- > hw/i386/pc.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index c6f6747..a03b384 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1225,6 +1225,10 @@ static void pc_build_feature_control_file(PCMachineState *pcms) > static void rtc_set_cpus_count(ISADevice *rtc, uint16_t cpus_count) > { > if (cpus_count > 0xff) { > + /* If the number of CPUs can't be represented in 8 bits, the > + * BIOS must use "etc/boot-cpus". Set RTC field to 0 just > + * to make old BIOSes fail more predictably. > + */ > rtc_set_memory(rtc, 0x5f, 0); > } else { > rtc_set_memory(rtc, 0x5f, cpus_count - 1);
On Fri, Oct 21, 2016 at 10:53:27AM +0200, Igor Mammedov wrote: > On Thu, 20 Oct 2016 16:51:48 -0200 > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > On Thu, Oct 20, 2016 at 04:58:42PM +0200, Igor Mammedov wrote: > > > Currently firmware uses 1 byte at 0x5F offset in RTC CMOS > > > to get number of CPUs present at boot. However 1 byte is > > > not enough to handle more than 255 CPUs. So add a new > > > fw_cfg file that would allow QEMU to tell it. > > > For compat reasons add file only for machine types that > > > support more than 255 CPUs. > > > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com> > > > > I suggest squashing this into the patch, to clarify why we are > > setting it to 0. > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > Could you squash it in while merging series? I will do.
On Fri, Oct 21, 2016 at 10:53:27AM +0200, Igor Mammedov wrote: > On Thu, 20 Oct 2016 16:51:48 -0200 > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > On Thu, Oct 20, 2016 at 04:58:42PM +0200, Igor Mammedov wrote: > > > Currently firmware uses 1 byte at 0x5F offset in RTC CMOS > > > to get number of CPUs present at boot. However 1 byte is > > > not enough to handle more than 255 CPUs. So add a new > > > fw_cfg file that would allow QEMU to tell it. > > > For compat reasons add file only for machine types that > > > support more than 255 CPUs. > > > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com> > > > > I suggest squashing this into the patch, to clarify why we are > > setting it to 0. > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > Could you squash it in while merging series? I'm not sure who's merging it (Eduardo do you want to?) if me, I'd rather see a clean repost, with a squash and acks included. > > --- > > hw/i386/pc.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > > index c6f6747..a03b384 100644 > > --- a/hw/i386/pc.c > > +++ b/hw/i386/pc.c > > @@ -1225,6 +1225,10 @@ static void pc_build_feature_control_file(PCMachineState *pcms) > > static void rtc_set_cpus_count(ISADevice *rtc, uint16_t cpus_count) > > { > > if (cpus_count > 0xff) { > > + /* If the number of CPUs can't be represented in 8 bits, the > > + * BIOS must use "etc/boot-cpus". Set RTC field to 0 just > > + * to make old BIOSes fail more predictably. > > + */ > > rtc_set_memory(rtc, 0x5f, 0); > > } else { > > rtc_set_memory(rtc, 0x5f, cpus_count - 1);
On Fri, Oct 28, 2016 at 01:08:32AM +0300, Michael S. Tsirkin wrote: > On Fri, Oct 21, 2016 at 10:53:27AM +0200, Igor Mammedov wrote: > > On Thu, 20 Oct 2016 16:51:48 -0200 > > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > > > On Thu, Oct 20, 2016 at 04:58:42PM +0200, Igor Mammedov wrote: > > > > Currently firmware uses 1 byte at 0x5F offset in RTC CMOS > > > > to get number of CPUs present at boot. However 1 byte is > > > > not enough to handle more than 255 CPUs. So add a new > > > > fw_cfg file that would allow QEMU to tell it. > > > > For compat reasons add file only for machine types that > > > > support more than 255 CPUs. > > > > > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com> > > > > > > I suggest squashing this into the patch, to clarify why we are > > > setting it to 0. > > > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > > > Could you squash it in while merging series? > > I'm not sure who's merging it (Eduardo do you want to?) > if me, I'd rather see a clean repost, with a squash and acks > included. It's already merged. See commit 080ac219cc7d9c55adf925c3545b7450055ad625.
diff --git a/hw/i386/pc.c b/hw/i386/pc.c index c6f6747..a03b384 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1225,6 +1225,10 @@ static void pc_build_feature_control_file(PCMachineState *pcms) static void rtc_set_cpus_count(ISADevice *rtc, uint16_t cpus_count) { if (cpus_count > 0xff) { + /* If the number of CPUs can't be represented in 8 bits, the + * BIOS must use "etc/boot-cpus". Set RTC field to 0 just + * to make old BIOSes fail more predictably. + */ rtc_set_memory(rtc, 0x5f, 0); } else { rtc_set_memory(rtc, 0x5f, cpus_count - 1);