linux-kernel - [PATCH] KVM: PPC: Enable CAP_SPAPR_TCE

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Message-ID: <20250109132053.158436-1-amachhiw@linux.ibm.com>
Date: Thu,  9 Jan 2025 18:50:53 +0530
From: Amit Machhiwal <amachhiw@...ux.ibm.com>
To: Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>, kvm-ppc@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org
Cc: Amit Machhiwal <amachhiw@...ux.ibm.com>,
        Vaibhav Jain <vaibhav@...ux.ibm.com>,
        Shivaprasad G Bhat <sbhat@...ux.ibm.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Naveen N Rao <naveen@...nel.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: [PATCH] KVM: PPC: Enable CAP_SPAPR_TCE_VFIO on pSeries KVM guests

Currently, on book3s-hv, the capability KVM_CAP_SPAPR_TCE_VFIO is only
available for KVM Guests running on PowerNV and not for the KVM guests
running on pSeries hypervisors. This prevents a pSeries hypervisor from
leveraging the in-kernel acceleration for H_PUT_TCE_INDIRECT and
H_STUFF_TCE hcalls that results in slow startup times for large memory
guests.

Fix this by enabling the CAP_SPAPR_TCE_VFIO on the pSeries hosts for the
nested PAPR guests.

Fixes: f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries")
Cc: stable@...r.kernel.org
Signed-off-by: Amit Machhiwal <amachhiw@...ux.ibm.com>
---
 arch/powerpc/kvm/powerpc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index ce1d91eed231..9c479c7381e4 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -554,7 +554,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = 1;
 		break;
 	case KVM_CAP_SPAPR_TCE_VFIO:
-		r = !!cpu_has_feature(CPU_FTR_HVMODE);
+		r = !!cpu_has_feature(CPU_FTR_HVMODE) || is_kvmppc_hv_enabled(kvm);
 		break;
 	case KVM_CAP_PPC_RTAS:
 	case KVM_CAP_PPC_FIXUP_HCALL:

base-commit: eea6e4b4dfb8859446177c32961c96726d0117be
-- 
2.47.1