From: Scott Wood <scottwood@freescale.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
linuxppc-dev@ozlabs.org, Alexander Graf <agraf@suse.de>,
Gleb Natapov <gleb@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation
Date: Thu, 30 May 2013 00:07:13 +0000 [thread overview]
Message-ID: <1369872433.18630.50@snotra> (raw)
In-Reply-To: <1369871852.3928.79.camel@pasglop> (from benh@kernel.crashing.org on Wed May 29 18:57:32 2013)
On 05/29/2013 06:57:32 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2013-05-29 at 18:38 -0500, Scott Wood wrote:
>
> > > Yes. I'd like to have them in. Their implementation is actually
> fairly
> > > trivial and they cannot be emulated by qemu if the rest of the
> XICS is
> > > in the kernel, so it's a problem.
> >
> > OK. Does it make more sense for you to take it as Paul suggested,
> or
> > for Gleb or Marcelo to pick it up directly?
>
> I'll take it.
Acked-by: Scott Wood <scottwood@freescale.com>
> > Then rm_action should always be 0 for these hcalls, right? So
> there's
> > no correctness reason to keep the hcalls in separate switch
> > statements. You shave off a few cycles checking rm_action, at the
> cost
> > of needing to change kvmppc_xics_hcall() if a real-mode version of
> > these hcalls is ever done.
>
> No, because rm_action will also be 0 if the hcall was fully done in
> real
> mode (which can happen, that's our fast path), in which case we do
> *NOT*
> want to to be re-done in virtual mode.
>
> That's why we always return whether rm_action is 0 or not when
> real-mode
> is enabled.
Oh, I misread the code and thought the decision to return was based on
the return value of kvmppc_xics_rm_complete. Sorry about that. :-(
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: kvm@vger.kernel.org, Gleb Natapov <gleb@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Alexander Graf <agraf@suse.de>,
kvm-ppc@vger.kernel.org, linuxppc-dev@ozlabs.org,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation
Date: Wed, 29 May 2013 19:07:13 -0500 [thread overview]
Message-ID: <1369872433.18630.50@snotra> (raw)
In-Reply-To: <1369871852.3928.79.camel@pasglop> (from benh@kernel.crashing.org on Wed May 29 18:57:32 2013)
On 05/29/2013 06:57:32 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2013-05-29 at 18:38 -0500, Scott Wood wrote:
>=20
> > > Yes. I'd like to have them in. Their implementation is actually =20
> fairly
> > > trivial and they cannot be emulated by qemu if the rest of the =20
> XICS is
> > > in the kernel, so it's a problem.
> >
> > OK. Does it make more sense for you to take it as Paul suggested, =20
> or
> > for Gleb or Marcelo to pick it up directly?
>=20
> I'll take it.
Acked-by: Scott Wood <scottwood@freescale.com>
> > Then rm_action should always be 0 for these hcalls, right? So =20
> there's
> > no correctness reason to keep the hcalls in separate switch
> > statements. You shave off a few cycles checking rm_action, at the =20
> cost
> > of needing to change kvmppc_xics_hcall() if a real-mode version of
> > these hcalls is ever done.
>=20
> No, because rm_action will also be 0 if the hcall was fully done in =20
> real
> mode (which can happen, that's our fast path), in which case we do =20
> *NOT*
> want to to be re-done in virtual mode.
>=20
> That's why we always return whether rm_action is 0 or not when =20
> real-mode
> is enabled.
Oh, I misread the code and thought the decision to return was based on =20
the return value of kvmppc_xics_rm_complete. Sorry about that. :-(
-Scott=
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>, <kvm-ppc@vger.kernel.org>,
<kvm@vger.kernel.org>, <linuxppc-dev@ozlabs.org>,
Alexander Graf <agraf@suse.de>, Gleb Natapov <gleb@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation
Date: Wed, 29 May 2013 19:07:13 -0500 [thread overview]
Message-ID: <1369872433.18630.50@snotra> (raw)
In-Reply-To: <1369871852.3928.79.camel@pasglop> (from benh@kernel.crashing.org on Wed May 29 18:57:32 2013)
On 05/29/2013 06:57:32 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2013-05-29 at 18:38 -0500, Scott Wood wrote:
>
> > > Yes. I'd like to have them in. Their implementation is actually
> fairly
> > > trivial and they cannot be emulated by qemu if the rest of the
> XICS is
> > > in the kernel, so it's a problem.
> >
> > OK. Does it make more sense for you to take it as Paul suggested,
> or
> > for Gleb or Marcelo to pick it up directly?
>
> I'll take it.
Acked-by: Scott Wood <scottwood@freescale.com>
> > Then rm_action should always be 0 for these hcalls, right? So
> there's
> > no correctness reason to keep the hcalls in separate switch
> > statements. You shave off a few cycles checking rm_action, at the
> cost
> > of needing to change kvmppc_xics_hcall() if a real-mode version of
> > these hcalls is ever done.
>
> No, because rm_action will also be 0 if the hcall was fully done in
> real
> mode (which can happen, that's our fast path), in which case we do
> *NOT*
> want to to be re-done in virtual mode.
>
> That's why we always return whether rm_action is 0 or not when
> real-mode
> is enabled.
Oh, I misread the code and thought the decision to return was based on
the return value of kvmppc_xics_rm_complete. Sorry about that. :-(
-Scott
next prev parent reply other threads:[~2013-05-30 0:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-24 1:42 [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation Paul Mackerras
2013-05-24 1:42 ` Paul Mackerras
2013-05-24 1:42 ` Paul Mackerras
2013-05-28 17:41 ` Scott Wood
2013-05-28 17:41 ` Scott Wood
2013-05-28 17:41 ` Scott Wood
2013-05-29 0:41 ` Benjamin Herrenschmidt
2013-05-29 0:41 ` Benjamin Herrenschmidt
2013-05-29 23:38 ` Scott Wood
2013-05-29 23:38 ` Scott Wood
2013-05-29 23:38 ` Scott Wood
2013-05-29 23:57 ` Benjamin Herrenschmidt
2013-05-29 23:57 ` Benjamin Herrenschmidt
2013-05-29 23:57 ` Benjamin Herrenschmidt
2013-05-30 0:07 ` Scott Wood [this message]
2013-05-30 0:07 ` Scott Wood
2013-05-30 0:07 ` Scott Wood
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