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Subject: Re: [PATCH] KVM: PPC: Book3S HV P9: Use kvm_arch_vcpu_get_wait() to
 get rcuwait object
From:   Sachin Sant <sachinp@linux.vnet.ibm.com>
In-Reply-To: <20211213174556.3871157-1-seanjc@google.com>
Date:   Tue, 14 Dec 2021 13:37:09 +0530
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Nicholas Piggin <npiggin@gmail.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Content-Transfer-Encoding: quoted-printable
Message-Id: <6D5BB54E-442E-4097-932B-7E0AC949D47C@linux.vnet.ibm.com>
References: <20211213174556.3871157-1-seanjc@google.com>
To:     Sean Christopherson <seanjc@google.com>
Precedence: bulk


> On 13-Dec-2021, at 11:15 PM, Sean Christopherson <seanjc@google.com> =
wrote:
>=20
> Use kvm_arch_vcpu_get_wait() to get a vCPU's rcuwait object instead of
> using vcpu->wait directly in kvmhv_run_single_vcpu().  Functionally, =
this
> is a nop as vcpu->arch.waitp is guaranteed to point at vcpu->wait.  =
But
> that is not obvious at first glance, and a future change coming in via
> the KVM tree, commit 510958e99721 ("KVM: Force PPC to define its own
> rcuwait object"), will hide vcpu->wait from architectures that define
> __KVM_HAVE_ARCH_WQP to prevent generic KVM from attepting to wake a =
vCPU
> with the wrong rcuwait object.
>=20
> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> =E2=80=94
>=20
Thanks for the patch.

Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>