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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	 Christian Zigotzky <chzigotzky@xenosoft.de>,
	linuxppc-dev@lists.ozlabs.org,  regressions@lists.linux.dev
Subject: Re: [PATCH] KVM: allow NULL writable argument to __kvm_faultin_pfn
Date: Wed, 8 Jan 2025 06:41:34 -0800	[thread overview]
Message-ID: <Z36OnrAGOL9c7cku@google.com> (raw)
In-Reply-To: <Z3wnsQQ67GBf1Vsb@google.com>

On Mon, Jan 06, 2025, Sean Christopherson wrote:
> On Wed, Jan 01, 2025, Paolo Bonzini wrote:
> > kvm_follow_pfn() is able to work with NULL in the .map_writable field
> > of the homonymous struct.  But __kvm_faultin_pfn() rejects the combo
> > despite KVM for e500 trying to use it.  Indeed .map_writable is not
> > particularly useful if the flags include FOLL_WRITE and readonly
> > guest memory is not supported, so add support to __kvm_faultin_pfn()
> > for this case.
> 
> I would prefer to keep the sanity check to minimize the risk of a page fault
> handler not supporting opportunistic write mappings.  e500 is definitely the
> odd one out here.

Per a quick chat at PUCK, Paolo is going to try and fix the e500 code to actually
use the @writable param as it's intended.


  reply	other threads:[~2025-01-08 14:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-01  6:49 [PATCH] KVM: allow NULL writable argument to __kvm_faultin_pfn Paolo Bonzini
2025-01-06 18:57 ` Sean Christopherson
2025-01-08 14:41   ` Sean Christopherson [this message]
2025-01-11 14:47   ` Christian Zigotzky
  -- strict thread matches above, loose matches on Subject: below --
2025-01-11 14:49 Christian Zigotzky

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