From: Claudio Imbrenda imbrenda@linux.ibm.com
commit 5ac14bac08ae827b619f21bcceaaac3b8c497e31 upstream.
Extend kvm_s390_shadow_fault to return the pointer to the valid leaf DAT table entry, or to the invalid entry.
Also return some flags in the lower bits of the address: PEI_DAT_PROT: indicates that DAT protection applies because of the protection bit in the segment (or, if EDAT, region) tables. PEI_NOT_PTE: indicates that the address of the DAT table entry returned does not refer to a PTE, but to a segment or region table.
Signed-off-by: Claudio Imbrenda imbrenda@linux.ibm.com Cc: stable@vger.kernel.org Reviewed-by: Janosch Frank frankja@de.ibm.com Reviewed-by: David Hildenbrand david@redhat.com Reviewed-by: Christian Borntraeger borntraeger@de.ibm.com Link: https://lore.kernel.org/r/20210302174443.514363-3-imbrenda@linux.ibm.com [borntraeger@de.ibm.com: fold in a fix from Claudio] Signed-off-by: Christian Borntraeger borntraeger@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/kvm/gaccess.c | 30 +++++++++++++++++++++++++----- arch/s390/kvm/gaccess.h | 6 +++++- arch/s390/kvm/vsie.c | 8 ++++---- 3 files changed, 34 insertions(+), 10 deletions(-)
--- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -976,7 +976,9 @@ int kvm_s390_check_low_addr_prot_real(st * kvm_s390_shadow_tables - walk the guest page table and create shadow tables * @sg: pointer to the shadow guest address space structure * @saddr: faulting address in the shadow gmap - * @pgt: pointer to the page table address result + * @pgt: pointer to the beginning of the page table for the given address if + * successful (return value 0), or to the first invalid DAT entry in + * case of exceptions (return value > 0) * @fake: pgt references contiguous guest memory block, not a pgtable */ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, @@ -1034,6 +1036,7 @@ static int kvm_s390_shadow_tables(struct rfte.val = ptr; goto shadow_r2t; } + *pgt = ptr + vaddr.rfx * 8; rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val); if (rc) return rc; @@ -1060,6 +1063,7 @@ shadow_r2t: rste.val = ptr; goto shadow_r3t; } + *pgt = ptr + vaddr.rsx * 8; rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val); if (rc) return rc; @@ -1087,6 +1091,7 @@ shadow_r3t: rtte.val = ptr; goto shadow_sgt; } + *pgt = ptr + vaddr.rtx * 8; rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val); if (rc) return rc; @@ -1123,6 +1128,7 @@ shadow_sgt: ste.val = ptr; goto shadow_pgt; } + *pgt = ptr + vaddr.sx * 8; rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val); if (rc) return rc; @@ -1157,6 +1163,8 @@ shadow_pgt: * @vcpu: virtual cpu * @sg: pointer to the shadow guest address space structure * @saddr: faulting address in the shadow gmap + * @datptr: will contain the address of the faulting DAT table entry, or of + * the valid leaf, plus some flags * * Returns: - 0 if the shadow fault was successfully resolved * - > 0 (pgm exception code) on exceptions while faulting @@ -1165,11 +1173,11 @@ shadow_pgt: * - -ENOMEM if out of memory */ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, - unsigned long saddr) + unsigned long saddr, unsigned long *datptr) { union vaddress vaddr; union page_table_entry pte; - unsigned long pgt; + unsigned long pgt = 0; int dat_protection, fake; int rc;
@@ -1191,8 +1199,20 @@ int kvm_s390_shadow_fault(struct kvm_vcp pte.val = pgt + vaddr.px * PAGE_SIZE; goto shadow_page; } - if (!rc) - rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val); + + switch (rc) { + case PGM_SEGMENT_TRANSLATION: + case PGM_REGION_THIRD_TRANS: + case PGM_REGION_SECOND_TRANS: + case PGM_REGION_FIRST_TRANS: + pgt |= PEI_NOT_PTE; + break; + case 0: + pgt += vaddr.px * 8; + rc = gmap_read_table(sg->parent, pgt, &pte.val); + } + if (datptr) + *datptr = pgt | dat_protection * PEI_DAT_PROT; if (!rc && pte.i) rc = PGM_PAGE_TRANSLATION; if (!rc && pte.z) --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -387,7 +387,11 @@ void ipte_unlock(struct kvm_vcpu *vcpu); int ipte_lock_held(struct kvm_vcpu *vcpu); int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
+/* MVPG PEI indication bits */ +#define PEI_DAT_PROT 2 +#define PEI_NOT_PTE 4 + int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *shadow, - unsigned long saddr); + unsigned long saddr, unsigned long *datptr);
#endif /* __KVM_S390_GACCESS_H */ --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -614,10 +614,10 @@ static int map_prefix(struct kvm_vcpu *v /* with mso/msl, the prefix lies at offset *mso* */ prefix += scb_s->mso;
- rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix); + rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL); if (!rc && (scb_s->ecb & ECB_TE)) rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, - prefix + PAGE_SIZE); + prefix + PAGE_SIZE, NULL); /* * We don't have to mprotect, we will be called for all unshadows. * SIE will detect if protection applies and trigger a validity. @@ -908,7 +908,7 @@ static int handle_fault(struct kvm_vcpu current->thread.gmap_addr, 1);
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, - current->thread.gmap_addr); + current->thread.gmap_addr, NULL); if (rc > 0) { rc = inject_fault(vcpu, rc, current->thread.gmap_addr, @@ -930,7 +930,7 @@ static void handle_last_fault(struct kvm { if (vsie_page->fault_addr) kvm_s390_shadow_fault(vcpu, vsie_page->gmap, - vsie_page->fault_addr); + vsie_page->fault_addr, NULL); vsie_page->fault_addr = 0; }