On Thu, Jun 01, 2023 at 02:54:54PM -0700, Suthikulpanit, Suravee wrote: > > > On 6/1/2023 6:09 PM, Michael S. Tsirkin wrote: > > On Thu, Jun 01, 2023 at 11:17:30AM +0100, Daniel P. Berrangé wrote: > > > On Thu, Jun 01, 2023 at 11:09:45AM +0100, Joao Martins wrote: > > > > > > > > On 31/05/2023 23:51, Suravee Suthikulpanit wrote: > > > > > Since KVM_MAX_VCPUS is currently defined to 1024 for x86 as shown in > > > > > arch/x86/include/asm/kvm_host.h, update QEMU limits to the same > > > > > number. > > > > > > > > > > In case KVM could not support the specified number of vcpus, QEMU > > > > > would > > > > > return the following error message: > > > > > > > > > > qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (xxx): > > > > > Invalid argument > > > > > > > > > > Signed-off-by: Suravee Suthikulpanit<suravee.suthikulpa...@amd.com> > > > > > --- > > > > > > > > > > Changes from V1: > > > > > (https://lore.kernel.org/all/ynkdgsii1vfvx...@redhat.com/T/) > > > > > * Bump from 512 to KVM_MAX_VCPUS (per Igor's suggestion) > > > > > > > > > > Note: > > > > > From the last discussion, Daniel mentioned that SMBIO 2.1 tables > > > > > might > > > > > cause overflow at approx 720 CPUs, and it might require using the > > > > > SMBIO 3.0 entry point. Also, we might need to change the default for > > > > > the x86 machine type to SMBIO 3.0. However, I do not know the status > > > > > of this. > > > > > > > > > I suspect smbios 3.0 (64-bit entry point) is already supported. > > > > > > > > With current qemu and all the smbios fixes in the last cycle, perhaps > > > > this is > > > > mainly just setting smbios_entry_point_type to > > > > SMBIOS_ENTRY_POINT_TYPE_64 if > > > > MachineState::smp::max_cpus is bigger than 720 (e.g. in pc_q35_init()?) > > > >> The need for the 64-bit entry point depends on a combination of > > > RAM > config > > > and CPU count. IMHO we need to unconditionally switch the latest machine > > > types to use the 64-bit entry point by default, rather than trying to > > > infer > > > some special condition to dynamically change on the fly. > > Yes, makes sense. > > Thanks all for the feedback. So, IIUC, here is how the SMBIOS entry point > types would be affected by the QEMU options: > > - pc-q35-8.1 and later, default to SMBIOS EP type 64. > - pc-q35-8.0 and older, default to SMBIOS EP type 32. > - User can override the type w/ QEMU option "-M .., > smbios-entry-point-type=[32|64]" > > Please let me know if I am missing anything. If this is accurate, I'll send > out v3 with this change.
Yes, and for pc-i440fx* too With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
