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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-05 10:38:11 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-05 10:38:11 -0700 |
commit | 0f5d752b1395e777ef81e28886945e5e939b7c8a (patch) | |
tree | 21da69238837da89f1e615640c28d4a91371af16 | |
parent | 905a6537e7640993fdbd18da6f56d86035069e88 (diff) | |
parent | a06afe8383080c630a7a528b8382fc6bb4925b61 (diff) | |
download | lwn-0f5d752b1395e777ef81e28886945e5e939b7c8a.tar.gz lwn-0f5d752b1395e777ef81e28886945e5e939b7c8a.zip |
Merge tag 's390-5.18-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Heiko Carstens:
- Disable -Warray-bounds warning for gcc12, since the only known way to
workaround false positive warnings on lowcore accesses would result
in worse code on fast paths.
- Avoid lockdep_assert_held() warning in kvm vm memop code.
- Reduce overhead within gmap_rmap code to get rid of long latencies
when e.g. shutting down 2nd level guests.
* tag 's390-5.18-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
KVM: s390: vsie/gmap: reduce gmap_rmap overhead
KVM: s390: Fix lockdep issue in vm memop
s390: disable -Warray-bounds
-rw-r--r-- | arch/s390/Makefile | 10 | ||||
-rw-r--r-- | arch/s390/kvm/kvm-s390.c | 11 | ||||
-rw-r--r-- | arch/s390/mm/gmap.c | 7 |
3 files changed, 27 insertions, 1 deletions
diff --git a/arch/s390/Makefile b/arch/s390/Makefile index e441b60b1812..df325eacf62d 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -30,6 +30,16 @@ KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g) KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,)) + +ifdef CONFIG_CC_IS_GCC + ifeq ($(call cc-ifversion, -ge, 1200, y), y) + ifeq ($(call cc-ifversion, -lt, 1300, y), y) + KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds) + KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, array-bounds) + endif + endif +endif + UTS_MACHINE := s390x STACK_SIZE := $(if $(CONFIG_KASAN),65536,16384) CHECKFLAGS += -D__s390__ -D__s390x__ diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index da3dabda1a12..76ad6408cb2c 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2384,7 +2384,16 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) return -EINVAL; if (mop->size > MEM_OP_MAX_SIZE) return -E2BIG; - if (kvm_s390_pv_is_protected(kvm)) + /* + * This is technically a heuristic only, if the kvm->lock is not + * taken, it is not guaranteed that the vm is/remains non-protected. + * This is ok from a kernel perspective, wrongdoing is detected + * on the access, -EFAULT is returned and the vm may crash the + * next time it accesses the memory in question. + * There is no sane usecase to do switching and a memop on two + * different CPUs at the same time. + */ + if (kvm_s390_pv_get_handle(kvm)) return -EINVAL; if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) { if (access_key_invalid(mop->key)) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index af03cacf34ec..1ac73917a8d3 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -1183,6 +1183,7 @@ EXPORT_SYMBOL_GPL(gmap_read_table); static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr, struct gmap_rmap *rmap) { + struct gmap_rmap *temp; void __rcu **slot; BUG_ON(!gmap_is_shadow(sg)); @@ -1190,6 +1191,12 @@ static inline void gmap_insert_rmap(struct gmap *sg, unsigned long vmaddr, if (slot) { rmap->next = radix_tree_deref_slot_protected(slot, &sg->guest_table_lock); + for (temp = rmap->next; temp; temp = temp->next) { + if (temp->raddr == rmap->raddr) { + kfree(rmap); + return; + } + } radix_tree_replace_slot(&sg->host_to_rmap, slot, rmap); } else { rmap->next = NULL; |