linux-kernel - Re: [PATCH v2] KVM: PPC: Book3S HV: relax check on H_SVM_INIT

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Message-ID: <20200527041649.GD293451@thinks.paulus.ozlabs.org>
Date:   Wed, 27 May 2020 14:16:49 +1000
From:   Paul Mackerras <paulus@...abs.org>
To:     Laurent Dufour <ldufour@...ux.ibm.com>
Cc:     kvm-ppc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, groug@...d.org, mpe@...erman.id.au,
        sukadev@...ux.ibm.com, linuxram@...ibm.com
Subject: Re: [PATCH v2] KVM: PPC: Book3S HV: relax check on H_SVM_INIT_ABORT

On Wed, May 20, 2020 at 07:43:08PM +0200, Laurent Dufour wrote:
> The commit 8c47b6ff29e3 ("KVM: PPC: Book3S HV: Check caller of H_SVM_*
> Hcalls") added checks of secure bit of SRR1 to filter out the Hcall
> reserved to the Ultravisor.
> 
> However, the Hcall H_SVM_INIT_ABORT is made by the Ultravisor passing the
> context of the VM calling UV_ESM. This allows the Hypervisor to return to
> the guest without going through the Ultravisor. Thus the Secure bit of SRR1
> is not set in that particular case.
> 
> In the case a regular VM is calling H_SVM_INIT_ABORT, this hcall will be
> filtered out in kvmppc_h_svm_init_abort() because kvm->arch.secure_guest is
> not set in that case.
> 
> Fixes: 8c47b6ff29e3 ("KVM: PPC: Book3S HV: Check caller of H_SVM_* Hcalls")
> Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>

Thanks, applied to my kvm-ppc-next branch.  I expanded the comment in
the code a little.

Paul.