From bd9166ffe624000140fc6b606b256df01fc0d060 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Fri, 24 Mar 2017 17:48:10 +1100 Subject: [PATCH] KVM: PPC: Book3S PR: Exit KVM on failed mapping At the moment kvmppc_mmu_map_page() returns -1 if mmu_hash_ops.hpte_insert() fails for any reason so the page fault handler resumes the guest and it faults on the same address again. This adds distinction to kvmppc_mmu_map_page() to return -EIO if mmu_hash_ops.hpte_insert() failed for a reason other than full pteg. At the moment only pSeries_lpar_hpte_insert() returns -2 if plpar_pte_enter() failed with a code other than H_PTEG_FULL. Other mmu_hash_ops.hpte_insert() instances can only fail with -1 "full pteg". With this change, if PR KVM fails to update HPT, it can signal the userspace about this instead of returning to guest and having the very same page fault over and over again. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_64_mmu_host.c | 5 ++++- arch/powerpc/kvm/book3s_pr.c | 6 +++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c index a587e8f4fd26..4b4e927c4822 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_host.c +++ b/arch/powerpc/kvm/book3s_64_mmu_host.c @@ -177,12 +177,15 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte, ret = mmu_hash_ops.hpte_insert(hpteg, vpn, hpaddr, rflags, vflags, hpsize, hpsize, MMU_SEGSIZE_256M); - if (ret < 0) { + if (ret == -1) { /* If we couldn't map a primary PTE, try a secondary */ hash = ~hash; vflags ^= HPTE_V_SECONDARY; attempt++; goto map_again; + } else if (ret < 0) { + r = -EIO; + goto out_unlock; } else { trace_kvm_book3s_64_mmu_map(rflags, hpteg, vpn, hpaddr, orig_pte); diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 633502f52bbb..ce437b98477e 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -625,7 +625,11 @@ int kvmppc_handle_pagefault(struct kvm_run *run, struct kvm_vcpu *vcpu, kvmppc_mmu_unmap_page(vcpu, &pte); } /* The guest's PTE is not mapped yet. Map on the host */ - kvmppc_mmu_map_page(vcpu, &pte, iswrite); + if (kvmppc_mmu_map_page(vcpu, &pte, iswrite) == -EIO) { + /* Exit KVM if mapping failed */ + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + return RESUME_HOST; + } if (data) vcpu->stat.sp_storage++; else if (vcpu->arch.mmu.is_dcbz32(vcpu) && -- GitLab