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From: Oliver Upton <oliver.upton@linux.dev>
To: Anish Moorthy <amoorthy@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Marc Zyngier <maz@kernel.org>,
	Sean Christopherson <seanjc@google.com>,
	James Houghton <jthoughton@google.com>,
	Ben Gardon <bgardon@google.com>,
	David Matlack <dmatlack@google.com>,
	Ricardo Koller <ricarkol@google.com>,
	Chao Peng <chao.p.peng@linux.intel.com>,
	Axel Rasmussen <axelrasmussen@google.com>, kvm@vger.kernel.org,
	kvmarm@lists.linux.dev
Subject: Re: [PATCH 7/8] kvm/arm64: Implement KVM_CAP_MEM_FAULT_NOWAIT for
 arm64
Message-ID: <Y+1s1txXLkwdlF6F@linux.dev>
References: <20230215011614.725983-1-amoorthy@google.com>
 <20230215011614.725983-8-amoorthy@google.com>
 <Y+0jcC/Em/cnYe9t@linux.dev>
 <CAF7b7mpbAdQtvXCQCk5kLrSn0bN=fLYVzEWXVW34OgBSxzHA_g@mail.gmail.com>
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On Wed, Feb 15, 2023 at 03:28:31PM -0800, Anish Moorthy wrote:
> On Wed, Feb 15, 2023 at 10:24 AM Oliver Upton <oliver.upton@linux.dev> wrote:
> >
> > All of Sean's suggestions about writing a change description apply here
> > too.
> 
> Ack
> 
> > > +     if (mem_fault_nowait && pfn == KVM_PFN_ERR_FAULT) {
> > > +             vcpu->run->exit_reason = KVM_EXIT_MEMORY_FAULT;
> > > +             vcpu->run->memory_fault.gpa = gfn << PAGE_SHIFT;
> > > +             vcpu->run->memory_fault.size = vma_pagesize;
> > > +             return -EFAULT;
> >
> > We really don't want to get out to userspace with EFAULT. Instead, we
> > should get out to userspace with 0 as the return code to indicate a
> > 'normal' / expected exit.
> >
> > That will require a bit of redefinition on user_mem_abort()'s return
> > values:
> >
> >  - < 0, return to userspace with an error
> >  - 0, return to userspace for a 'normal' exit
> >  - 1, resume the guest
> 
> Ok, easy enough: do you want that patch sent separately or as part
> of the next version of this series?

Roll it into the next spin of the series. Splitting off patches (as asked
in patch 1) is only useful if there's a bugfix or some other reason for
inclusion ahead of the entire series.

-- 
Thanks,
Oliver