linux-kernel - Re: [PATCH 2/2] KVM: PPC: Book3S HV: H_SVM_INIT_START must call UV

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Date:   Fri, 20 Mar 2020 17:47:51 -0700
From:   Ram Pai <linuxram@...ibm.com>
To:     Laurent Dufour <ldufour@...ux.ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        kvm-ppc@...r.kernel.org, Bharata B Rao <bharata@...ux.ibm.com>
Subject: Re:  [PATCH 2/2] KVM: PPC: Book3S HV: H_SVM_INIT_START must call UV_RETURN

On Fri, Mar 20, 2020 at 11:26:43AM +0100, Laurent Dufour wrote:
> When the call to UV_REGISTER_MEM_SLOT is failing, for instance because
> there is not enough free secured memory, the Hypervisor (HV) has to call
			   secure memory,

> UV_RETURN to report the error to the Ultravisor (UV). Then the UV will call
> H_SVM_INIT_ABORT to abort the securing phase and go back to the calling VM.
> 
> If the kvm->arch.secure_guest is not set, in the return path rfid is called
> but there is no valid context to get back to the SVM since the Hcall has
> been routed by the Ultravisor.
> 
> Move the setting of kvm->arch.secure_guest earlier in
> kvmppc_h_svm_init_start() so in the return path, UV_RETURN will be called
> instead of rfid.
> 
> Cc: Bharata B Rao <bharata@...ux.ibm.com>
> Cc: Paul Mackerras <paulus@...abs.org>
> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>

Reviewed-by: Ram Pai <linuxram@...ibm.com>