On 2020/7/14 20:23, Marc Zyngier wrote: > On 2020-07-14 13:15, zhukeqian wrote: >> Hi Marc, >> >> On 2020/7/14 19:34, Marc Zyngier wrote: >>> Hi Keqian, >>> >>> On 2020-07-14 03:20, zhukeqian wrote: >>>> Hi all, >>>> >>>> We are studying Enhanced Counter Virtualization (introduced by ARMv8.6 >>>> extension), and here is a question >>>> raised by Biaoxiang Ye <yebiaoxiang@xxxxxxxxxx>: >>>> >>>> Described in the ARMv8.6 Extension Specification: >>>> Note: the scaling factor CNTSCALE is designed as a 2.62 bit fixed >>>> point number, so permitting a scaling up by >>>> (nearly) a factor 4. The scaling factor CNTISCALE is signed as an 8.56 >>>> number for the scaling of the values >>>> written into the timers for comparison with the actual count. This >>>> implies that the greatest scaling down of the >>>> counter supported in (nearly) a factor of *512*. >>>> >>>> We think the number "512" should be "256" (2^8), or do we miss something? >>> >>> This register doesn't seem to be described in ARM DDI 0487F.b, >>> which is the official documentation and does contain the ARMv8.6 >>> material, including ARMv8.6-ECV. >>> >>> Either you are looking at confidential information (and nobody >>> can answer you in public), or obsolete information (and nobody >>> knows what this is about). >>> >> Well, it's alpha release version :( . Many thanks! > > Wow. I suggest you discard this document, as it is obsolete. > ARMv8.6 is a released version of the architecture, and > everything should be in the ARM ARM. OK, there are many difference :) . Thanks, Keqian > > M. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
