Hi Oliver, On Fri, Jul 21, 2023 at 2:18 PM Oliver Upton <oliver.upton@xxxxxxxxx> wrote: > > On Tue, Jul 18, 2023 at 04:45:18PM +0000, Jing Zhang wrote: > > From: Oliver Upton <oliver.upton@xxxxxxxxx> > > > > The debug architecture is mandatory in ARMv8, so KVM should not allow > > userspace to configure a vCPU with less than that. Of course, this isn't > > handled elegantly by the generic ID register plumbing, as the respective > > ID register fields have a nonzero starting value. > > > > Add an explicit check for debug versions less than v8 of the > > architecture. > > > > Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx> > > Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx> > > This patch needs to be broken up. You're doing a couple things: > > 1) Forcing the behavior of the DebugVer field to be FTR_LOWER_SAFE, and > adding the necessary check for a valid version > > 2) Changing KVM's value for the field to expose up to Debugv8p8 to the > guest. > > The latter isn't described in the changelog at all, and worse yet the > ordering of the series is not bisectable. Changing the default value of > the field w/o allowing writes breaks migration. > > So, please split this patch in two and consider stacking like so: > > - Change #1 above (field sanitization) > > - "KVM: arm64: Enable writable for ID_AA64DFR0_EL1 and ID_DFR0_EL1" > > - Change #2 above (advertise up to v8p8) > > -- > Thanks, > Oliver Sure, I'll split it as you suggested. Thanks, Jing
