Re: [PATCH 06/11] KVM: PPC: Book3S HV: Support POWER6 compatibility mode on POWER7

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Paul Mackerras <paulus@xxxxxxxxx> writes:

> This enables us to use the Processor Compatibility Register (PCR) on
> POWER7 to put the processor into architecture 2.05 compatibility mode
> when running a guest.  In this mode the new instructions and registers
> that were introduced on POWER7 are disabled in user mode.  This
> includes all the VSX facilities plus several other instructions such
> as ldbrx, stdbrx, popcntw, popcntd, etc.
>
> To select this mode, we have a new register accessible through the
> set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT.  Setting
> this to zero gives the full set of capabilities of the processor.
> Setting it to one of the "logical" PVR values defined in PAPR puts
> the vcpu into the compatibility mode for the corresponding
> architecture level.  The supported values are:
>
> 0x0f000002	Architecture 2.05 (POWER6)
> 0x0f000003	Architecture 2.06 (POWER7)
> 0x0f100003	Architecture 2.06+ (POWER7+)
>
> Since the PCR is per-core, the architecture compatibility level and
> the corresponding PCR value are stored in the struct kvmppc_vcore, and
> are therefore shared between all vcpus in a virtual core.

We already have KVM_SET_SREGS taking pvr as argument. Can't we do
this kvmppc_set_pvr ?. Can you also share the qemu changes ? There I
guess we need to do update the "cpu-version" in the device tree so
that /proc/cpuinfo shows the right information in the guest 


-aneesh

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