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From: David Gibson <david@gibson.dropbear.id.au>
To: Bharata B Rao <bharata@linux.ibm.com>
Cc: aneesh.kumar@linux.ibm.com, npiggin@gmail.com,
	kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v1 1/2] KVM: PPC: Book3S HV: Add support for H_RPT_INVALIDATE (nested case only)
Date: Mon, 14 Dec 2020 17:05:59 +1100	[thread overview]
Message-ID: <20201214060559.GH4717@yekko.fritz.box> (raw)
In-Reply-To: <20201211103336.GB775394@in.ibm.com>

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On Fri, Dec 11, 2020 at 04:03:36PM +0530, Bharata B Rao wrote:
> On Mon, Oct 19, 2020 at 04:56:41PM +0530, Bharata B Rao wrote:
> > Implements H_RPT_INVALIDATE hcall and supports only nested case
> > currently.
> > 
> > A KVM capability KVM_CAP_RPT_INVALIDATE is added to indicate the
> > support for this hcall.
> 
> As Paul mentioned in the thread, this hcall does both process scoped
> invalidations and partition scoped invalidations for L2 guest.
> I am adding KVM_CAP_RPT_INVALIDATE capability with only partition
> scoped invalidations (nested case) implemented in the hcall as we
> don't see the need for KVM to implement process scoped invalidation
> function as KVM may never run with LPCR[GTSE]=0.
> 
> I am wondering if enabling the capability with only partial
> implementation of the hcall is the correct thing to do. In future
> if we ever want process scoped invalidations support in this hcall,
> we may not be able to differentiate the availability of two functions
> cleanly from QEMU.

Yeah, it's not ideal.

> So does it make sense to implement the process scoped invalidation
> function also now itself even if it is not going to be used in
> KVM?

That might be a good idea, if it's not excessively difficult.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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  reply	other threads:[~2020-12-14  9:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19 11:26 [PATCH v1 0/2] Use H_RPT_INVALIDATE for nested guest Bharata B Rao
2020-10-19 11:26 ` [PATCH v1 1/2] KVM: PPC: Book3S HV: Add support for H_RPT_INVALIDATE (nested case only) Bharata B Rao
2020-12-09  4:15   ` Paul Mackerras
2020-12-10  4:24     ` Bharata B Rao
2020-12-11  1:16       ` David Gibson
2020-12-11  5:27         ` Paul Mackerras
2020-12-14  6:05           ` David Gibson
2020-12-11 10:33   ` Bharata B Rao
2020-12-14  6:05     ` David Gibson [this message]
2020-10-19 11:26 ` [PATCH v1 2/2] KVM: PPC: Book3S HV: Use H_RPT_INVALIDATE in nested KVM Bharata B Rao
2020-11-24  9:44 ` [PATCH v1 0/2] Use H_RPT_INVALIDATE for nested guest Bharata B Rao

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