On Mon, Oct 31, 2016 at 11:28:23AM +1100, Suraj Jitindar Singh wrote:
> The function kvmppc_set_arch_compat() is used to determine the value of the
> processor compatibility register (PCR) for a guest running in a given
> compatibility mode. There is currently no support for v3.00 of the ISA.
>
> Add support for v3.00 of the ISA which adds an ISA v2.07 compatilibity mode
> to the PCR.
>
> We also add a check to ensure the processor we are running on is capable of
> emulating the chosen processor (for example a POWER7 cannot emulate a
> POWER8, similarly with a POWER8 and a POWER9).
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv.c | 32 +++++++++++++++++++++++---------
> 1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 3686471..24681e7 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -311,24 +311,38 @@ static int kvmppc_set_arch_compat(struct kvm_vcpu *vcpu, u32 arch_compat)
> * If an arch bit is set in PCR, all the defined
> * higher-order arch bits also have to be set.
> */
> - pcr = PCR_ARCH_206 | PCR_ARCH_205;
> + if (cpu_has_feature(CPU_FTR_ARCH_206))
> + pcr |= PCR_ARCH_205;
> + if (cpu_has_feature(CPU_FTR_ARCH_207S))
> + pcr |= PCR_ARCH_206;
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + pcr |= PCR_ARCH_207;
> break;
> case PVR_ARCH_206:
> case PVR_ARCH_206p:
> - pcr = PCR_ARCH_206;
> + /* Must be at least v2.06 to (emulate) it */
> + if (!cpu_has_feature(CPU_FTR_ARCH_206))
> + return -EINVAL;
> + if (cpu_has_feature(CPU_FTR_ARCH_207S))
> + pcr |= PCR_ARCH_206;
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + pcr |= PCR_ARCH_207;
> break;
> case PVR_ARCH_207:
> + /* Must be at least v2.07 to (emulate) it */
> + if (!cpu_has_feature(CPU_FTR_ARCH_207S))
> + return -EINVAL;
> + if (cpu_has_feature(CPU_FTR_ARCH_300))
> + pcr |= PCR_ARCH_207;
> + break;
> + case PVR_ARCH_300:
> + /* Must be at least v3.00 to (emulate) it */
> + if (!cpu_has_feature(CPU_FTR_ARCH_300))
> + return -EINVAL;
> break;
I can't help thinking that the repetitive structure of the lines
you're adding must imply a regularity that could be expressed more
concisely. If you defined a dummy PCR_ARCH_300 bit as 0x10, perhaps
you could do something like this:
if (cpu_has_feature(CPU_FTR_ARCH_300))
host_pcr_bit = PCR_ARCH_300;
else if (cpu_has_feature(CPU_FTR_ARCH_207S))
host_pcr_bit = PCR_ARCH_207;
else
host_pcr_bit = PCR_ARCH_206;
switch (arch_compat) {
case PVR_ARCH_205:
guest_pcr_bit = PCR_ARCH_205;
break;
case PVR_ARCH_206:
guest_pcr_bit = PCR_ARCH_206;
break;
case PVR_ARCH_207:
case PVR_ARCH_207S:
guest_pcr_bit = PCR_ARCH_207;
break;
case PVR_ARCH_300:
guest_pcr_bit = PCR_ARCH_300;
break;
default:
return -EINVAL;
}
if (guest_pcr_bit > host_pcr_bit)
return -EINVAL;
pcr = host_pcr_bit - guest_pcr_bit;
The translation from arch_compat to guest_pcr_bit might look neater as
a table lookup on the low bits of arch_compat, after a bounds check.
Paul.
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