Hi David, All,
I am revisiting/reviving this patch.
On 5/5/21 11:20, David Gibson wrote:
On Wed, Apr 21, 2021 at 11:50:40AM +0530, Ravi Bangoria wrote:
Hi David,
On 4/19/21 10:23 AM, David Gibson wrote:
On Mon, Apr 12, 2021 at 05:14:33PM +0530, Ravi Bangoria wrote:
<snip>
Since we have released versions with POWER10 support, but no DAWR1, in
theory we need a capability so new qemu with old machine types don't
gain guest visible features that the same machine types on older qemus
had.
Except.. there's a loophole we might use to sidestep that. The
current POWER10 CPU modelled in qemu is a DD1 - which I strongly
suspect will never appear outside of IBM. I'm pretty sure we want to
replace that with a DD2.
While the modelled CPU is DD1, I think it's pretty reasonable to say
our POWER10 support hasn't yet stabilized, and it would therefore be
ok to simply add DAWR1 on POWER10 unconditionally, as long as we do it
before we switch over to DD2.
As POWER10 DD2 switch over has already happened, the need for
new/separate capability for dawr1 still holds. So, I am keeping it as is.
Posting the next version after rebase.
Thanks,
Shivaprasad
I'm wondering if we're actually just better off setting the pa feature
just based on the guest CPU model. TCG will be broken if you try to
use it, but then, it already is. AFAIK there's no inherent reason we
couldn't implement DAWR support in TCG, it's just never been worth the
trouble.
Correct. Probably there is no practical usecase for DAWR in TCG mode.
Thanks,
Ravi
