On Wed, Oct 17, 2012 at 02:57:15AM +0000, Wei, Bing (WeiBing, MCXS-SH) wrote: > For pCPU/core and VCPUS/logical cpu mapping, It should be 8 multiple. 254 is > reasonable. Or something I miss? > I am not sure what do you mean. Can you clarify?
> -----Original Message----- > From: kvm-ow...@vger.kernel.org [mailto:kvm-ow...@vger.kernel.org] On Behalf > Of Vinod, Chegu > Sent: Sunday, October 14, 2012 9:43 PM > To: Gleb Natapov > Cc: Sasha Levin; KVM > Subject: Re: KVM_MAX_VCPUS > > On 10/14/2012 2:08 AM, Gleb Natapov wrote: > > On Sat, Oct 13, 2012 at 10:32:13PM -0400, Sasha Levin wrote: > >> On 10/13/2012 06:29 PM, Chegu Vinod wrote: > >>> Hello, > >>> > >>> Wanted to get a clarification about KVM_MAX_VCPUS(currently set to 254) > >>> in kvm_host.h file. The kvm_vcpu *vcpus array is sized based on > >>> KVM_MAX_VCPUS. > >>> (i.e. a max of 254 elements in the array). > >>> > >>> An 8bit APIC id should allow for 256 ID's. Reserving one for Broadcast > >>> should > >>> leave 255 ID's. Is there one more ID reserved for some other purpose ? > >>> (hence > >>> leading to KVM_MAX_VCPUS being set to 254 and not 255). > >> Another ID goes to the IO-APIC. > >> > > This is not really needed on KVM. We can enlarge KVM_MAX_VCPUS to 255. > > Thanks for clarification! ( We did suspect the IO-APIC...but weren't > quite sure). > > Vinod > > > > -- > > Gleb. > > . > > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
