From ded13fc11b71fd1351e57c68a130d89a0285f1b6 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 22 Nov 2017 14:38:53 +1100 Subject: [PATCH] KVM: PPC: Book3S HV: Fix migration and HPT resizing of HPT guests on radix hosts This fixes two errors that prevent a guest using the HPT MMU from successfully migrating to a POWER9 host in radix MMU mode, or resizing its HPT when running on a radix host. The first bug was that commit 8dc6cca556e4 ("KVM: PPC: Book3S HV: Don't rely on host's page size information", 2017-09-11) missed two uses of hpte_base_page_size(), one in the HPT rehashing code and one in kvm_htab_write() (which is used on the destination side in migrating a HPT guest). Instead we use kvmppc_hpte_base_page_shift(). Having the shift count means that we can use left and right shifts instead of multiplication and division in a few places. Along the way, this adds a check in kvm_htab_write() to ensure that the page size encoding in the incoming HPTEs is recognized, and if not return an EINVAL error to userspace. The second bug was that kvm_htab_write was performing some but not all of the functions of kvmhv_setup_mmu(), resulting in the destination VM being left in radix mode as far as the hardware is concerned. The simplest fix for now is make kvm_htab_write() call kvmppc_setup_partition_table() like kvmppc_hv_setup_htab_rma() does. In future it would be better to refactor the code more extensively to remove the duplication. Fixes: 8dc6cca556e4 ("KVM: PPC: Book3S HV: Don't rely on host's page size information") Fixes: 7a84084c6054 ("KVM: PPC: Book3S HV: Set partition table rather than SDR1 on POWER9") Reported-by: Suraj Jitindar Singh Tested-by: Suraj Jitindar Singh Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/kvm_ppc.h | 1 + arch/powerpc/kvm/book3s_64_mmu_hv.c | 37 ++++++++++++++++++----------- arch/powerpc/kvm/book3s_hv.c | 3 +-- 3 files changed, 25 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 96753f3aac6d..941c2a3f231b 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -180,6 +180,7 @@ extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm, struct iommu_group *grp); extern int kvmppc_switch_mmu_to_hpt(struct kvm *kvm); extern int kvmppc_switch_mmu_to_radix(struct kvm *kvm); +extern void kvmppc_setup_partition_table(struct kvm *kvm); extern long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, struct kvm_create_spapr_tce_64 *args); diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 235319c2574e..966097232d21 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -1238,8 +1238,9 @@ static unsigned long resize_hpt_rehash_hpte(struct kvm_resize_hpt *resize, unsigned long vpte, rpte, guest_rpte; int ret; struct revmap_entry *rev; - unsigned long apsize, psize, avpn, pteg, hash; + unsigned long apsize, avpn, pteg, hash; unsigned long new_idx, new_pteg, replace_vpte; + int pshift; hptep = (__be64 *)(old->virt + (idx << 4)); @@ -1298,8 +1299,8 @@ static unsigned long resize_hpt_rehash_hpte(struct kvm_resize_hpt *resize, goto out; rpte = be64_to_cpu(hptep[1]); - psize = hpte_base_page_size(vpte, rpte); - avpn = HPTE_V_AVPN_VAL(vpte) & ~((psize - 1) >> 23); + pshift = kvmppc_hpte_base_page_shift(vpte, rpte); + avpn = HPTE_V_AVPN_VAL(vpte) & ~(((1ul << pshift) - 1) >> 23); pteg = idx / HPTES_PER_GROUP; if (vpte & HPTE_V_SECONDARY) pteg = ~pteg; @@ -1311,20 +1312,20 @@ static unsigned long resize_hpt_rehash_hpte(struct kvm_resize_hpt *resize, offset = (avpn & 0x1f) << 23; vsid = avpn >> 5; /* We can find more bits from the pteg value */ - if (psize < (1ULL << 23)) - offset |= ((vsid ^ pteg) & old_hash_mask) * psize; + if (pshift < 23) + offset |= ((vsid ^ pteg) & old_hash_mask) << pshift; - hash = vsid ^ (offset / psize); + hash = vsid ^ (offset >> pshift); } else { unsigned long offset, vsid; /* We only have 40 - 23 bits of seg_off in avpn */ offset = (avpn & 0x1ffff) << 23; vsid = avpn >> 17; - if (psize < (1ULL << 23)) - offset |= ((vsid ^ (vsid << 25) ^ pteg) & old_hash_mask) * psize; + if (pshift < 23) + offset |= ((vsid ^ (vsid << 25) ^ pteg) & old_hash_mask) << pshift; - hash = vsid ^ (vsid << 25) ^ (offset / psize); + hash = vsid ^ (vsid << 25) ^ (offset >> pshift); } new_pteg = hash & new_hash_mask; @@ -1801,6 +1802,7 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf, ssize_t nb; long int err, ret; int mmu_ready; + int pshift; if (!access_ok(VERIFY_READ, buf, count)) return -EFAULT; @@ -1855,6 +1857,9 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf, err = -EINVAL; if (!(v & HPTE_V_VALID)) goto out; + pshift = kvmppc_hpte_base_page_shift(v, r); + if (pshift <= 0) + goto out; lbuf += 2; nb += HPTE_SIZE; @@ -1869,14 +1874,18 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf, goto out; } if (!mmu_ready && is_vrma_hpte(v)) { - unsigned long psize = hpte_base_page_size(v, r); - unsigned long senc = slb_pgsize_encoding(psize); - unsigned long lpcr; + unsigned long senc, lpcr; + senc = slb_pgsize_encoding(1ul << pshift); kvm->arch.vrma_slb_v = senc | SLB_VSID_B_1T | (VRMA_VSID << SLB_VSID_SHIFT_1T); - lpcr = senc << (LPCR_VRMASD_SH - 4); - kvmppc_update_lpcr(kvm, lpcr, LPCR_VRMASD); + if (!cpu_has_feature(CPU_FTR_ARCH_300)) { + lpcr = senc << (LPCR_VRMASD_SH - 4); + kvmppc_update_lpcr(kvm, lpcr, + LPCR_VRMASD); + } else { + kvmppc_setup_partition_table(kvm); + } mmu_ready = 1; } ++i; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 79ea3d9269db..2d46037ce936 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -120,7 +120,6 @@ MODULE_PARM_DESC(h_ipi_redirect, "Redirect H_IPI wakeup to a free host core"); static void kvmppc_end_cede(struct kvm_vcpu *vcpu); static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu); -static void kvmppc_setup_partition_table(struct kvm *kvm); static inline struct kvm_vcpu *next_runnable_thread(struct kvmppc_vcore *vc, int *ip) @@ -3574,7 +3573,7 @@ static void kvmppc_mmu_destroy_hv(struct kvm_vcpu *vcpu) return; } -static void kvmppc_setup_partition_table(struct kvm *kvm) +void kvmppc_setup_partition_table(struct kvm *kvm) { unsigned long dw0, dw1; -- GitLab