On Mon, 20 Dec 2021 07:04:44 +0000, Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx> wrote: > > > On 30-11-2021 01:30 am, Marc Zyngier wrote: > > KVM internally uses accessor functions when reading or writing the > > guest's system registers. This takes care of accessing either the stored > > copy or using the "live" EL1 system registers when the host uses VHE. > > > > With the introduction of virtual EL2 we add a bunch of EL2 system > > registers, which now must also be taken care of: > > - If the guest is running in vEL2, and we access an EL1 sysreg, we must > > revert to the stored version of that, and not use the CPU's copy. > > - If the guest is running in vEL1, and we access an EL2 sysreg, we must > > Do we have vEL1? or is it a typo? Not a typo, but only a convention (there is no such concept in the architecture). vELx denotes the exception level the guest thinks it is running at while running at EL1 (as it is the case for both vEL1 and vEL2). Depending on the exception level and the running mode (VHE or not) you emulate at any given time, you access the sysregs differently: they can be either live in the CPU, stored in memory, with or without translation. That's why I'm using these 'parallel' exception levels to denote which is which... HTH, M. -- Without deviation from the norm, progress is not possible.
