Re: [PATCH 0/2] Fix handling of h_set_dawr

On Mon, 2019-06-17 at 11:06 +0200, Cédric Le Goater wrote:

On 17/06/2019 09:16, Suraj Jitindar Singh wrote:

quoted

Series contains 2 patches to fix the host in kernel handling of the
hcall
h_set_dawr.

First patch from Michael Neuling is just a resend added here for
clarity.

Michael Neuling (1):
  KVM: PPC: Book3S HV: Fix r3 corruption in h_set_dabr()

Suraj Jitindar Singh (1):
  KVM: PPC: Book3S HV: Only write DAWR[X] when handling h_set_dawr
in
    real mode

Reviewed-by: Cédric Le Goater <clg@kaod.org>

and 

Tested-by: Cédric Le Goater <clg@kaod.org>


but I see slowdowns in nested as if the IPIs were not delivered. Have
we
touch this part in 5.2 ? 

Hi,

I've seen the same and tracked it down to decrementer exceptions not
being delivered when the guest is using large decrementer. I've got a
patch I'm about to send so I'll CC you.

Another option is to disable the large decrementer with:
-machine pseries,cap-large-decr=false

Thanks,
Suraj

Thanks,

C.