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From: Fabiano Rosas <farosas@linux.ibm.com>
In-Reply-To: <20190304055018.GM7792@umbus.fritz.box>
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Date: Fri, 08 Mar 2019 16:09:56 -0300
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Message-Id: <87o96luqrf.fsf@linux.ibm.com>
Subject: Re: [Qemu-devel] [RFC PATCH v4 2/5] kvm-all: Introduce
 kvm_set_singlestep
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To: David Gibson <david@gibson.dropbear.id.au>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Richard Henderson <rth@twiddle.net>

David Gibson <david@gibson.dropbear.id.au> writes:

>> +/* Whether the KVM_SET_GUEST_DEBUG ioctl supports single stepping */
>> +int kvm_has_guestdbg_singlestep(void)
>> +{
>> +    /* return kvm_check_extension(kvm_state, KVM_CAP_GUEST_DEBUG_SSTEP); */
>
> I don't see a KVM_CAP_GUEST_DEBUG_SSTEP in either the qemu or kernel
> trees.  Where does that come from?
>

I realized that this will cause a regression for the other architectures
(and even PPC-PR) that already have the feature when we run QEMU on
older kernels without this capability.

I am becoming inclined to rely on kvmppc_is_pr. Do you see another way
around this?