Re: [Qemu-devel] [PATCH v4 00/13] pc: q35: x2APIC support in kvm_apic mode

[Daniel P. Berrange]

On Wed, Oct 19, 2016 at 02:05:30PM +0200, Igor Mammedov wrote:
> 
> Changes since v3:
>   - fix endianness issues when filling MADT/SRAT entries (Eduardo)
>   - squash "acpi: cphp: support x2APIC entry in cpu._MAT" into
>     "pc: acpi: x2APIC support for MADT table and _MAT method" (Eduardo)
>   - keep assert() as it doesn't affect x2APIC cpus in bochs_bios_init() 
> (Eduardo)
>   - restore kvm_has_x2apic_api() and use it to avoid side-effects
>     of kvm_enable_x2apic(). x2APIC API will be enabled by iommu
>     if it's present or not enabled at all. (Radim)
>   - add intel iommu example to error message (Eduardo)
> 
> Changes since v2:
>   - rebase on top of EIM fixes
>   - drop kvm_has_x2apic_ids() and reuse kvm_enable_x2apic()
>     from Radim's EIM fixes
>   - fix hang on reboot in BIOS due to not updated 'etc/boot-cpus' fwcfg file
>     after CPU hotplug
>   - drop not used anymore pc_present_cpus_count() and incrementally count
>     present VCPUs as they are added/removed at (un)plug callbacks time
> 
> Changes since v1:
>   - rebase on top of 2.7
>   - drop add 2.8 machine and linux headers update patches
>   - drop numa related patches (will post separately as unrelated)
>   - change default mc->maxcpus only for q35
> 
> Changes since RFC:
>   - use new KVM_CAP_X2APIC_API to detect x2APIC IDs support
>   - rebase on top of 2.7-rc1, since many deps were merged
>   - fix etc/boot-cpus to account for -device provided cpus
>   - include not yet merged _PXM fix as prereq
>   - add 2.8 machine type and bump up maxcpus count since it
> 
> Series extends current CPU/kvm_apic/Q35 machine
> code to support x2APIC and upto 288 VCPUs when QEMU
> is used with KVM's lapic.
> 
> Due to FW_CFG_MAX_CPUS (which is actually apic_id_limit)
> being limited to uint16_t, the max possible APIC ID is
> limitted to 2^16 with this series but that should
> be sufficient for bumping VCPUs number for quite a while.

Not a problem, just curiosity - 2^16 gives us 65536, so where
is the 288 limit coming from ?

Regards,
Daniel
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