From 99b99032a89e67debd6742d773d8ad271b042df7 Mon Sep 17 00:00:00 2001 From: Amit Machhiwal Date: Thu, 20 Feb 2025 12:30:02 +0530 Subject: [PATCH] KVM: PPC: Enable CAP_SPAPR_TCE_VFIO on pSeries KVM guests commit b4392813bbc3b05fc01a33c64d8b8c6c62c32cfa upstream. 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 L2 guest 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. Support for VFIO on pSeries was restored in commit f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries"), making it possible to re-enable this capability on pSeries hosts. This change enables KVM_CAP_SPAPR_TCE_VFIO for nested PAPR guests on pSeries, while maintaining the existing behavior on PowerNV. Booting an L2 guest with 128GB of memory shows an average 11% improvement in startup time. Fixes: f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries") Cc: stable@vger.kernel.org Reviewed-by: Vaibhav Jain Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Amit Machhiwal Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20250220070002.1478849-1-amachhiw@linux.ibm.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kvm/powerpc.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index f14329989e9a7..4b6ce4f07bc2c 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -550,12 +550,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) #ifdef CONFIG_PPC_BOOK3S_64 case KVM_CAP_SPAPR_TCE: + fallthrough; case KVM_CAP_SPAPR_TCE_64: - r = 1; - break; case KVM_CAP_SPAPR_TCE_VFIO: - r = !!cpu_has_feature(CPU_FTR_HVMODE); - break; case KVM_CAP_PPC_RTAS: case KVM_CAP_PPC_FIXUP_HCALL: case KVM_CAP_PPC_ENABLE_HCALL: