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Wed, 25 Jan 2023 21:26:16 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 983D620043; Wed, 25 Jan 2023 21:26:16 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 25 Jan 2023 21:26:16 +0000 (GMT) From: Janis Schoetterl-Glausch To: Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev Cc: Janis Schoetterl-Glausch , David Hildenbrand , Jonathan Corbet , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, Paolo Bonzini , Shuah Khan , Sven Schnelle Subject: [PATCH v6 00/14] KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg Date: Wed, 25 Jan 2023 22:25:54 +0100 Message-Id: <20230125212608.1860251-1-scgl@linux.ibm.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: sgSVheK_YzRHjsmJKAgKb6u87iqQBKSp X-Proofpoint-ORIG-GUID: m4AEZ-n6GenYyUqygkJJM6xipWk9Jhnm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-25_13,2023-01-25_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 phishscore=0 mlxlogscore=999 clxscore=1015 spamscore=0 adultscore=0 priorityscore=1501 malwarescore=0 bulkscore=0 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301250187 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1756031666904630096?= X-GMAIL-MSGID: =?utf-8?q?1756031667195311157?= User space can use the MEM_OP ioctl to make storage key checked reads and writes to the guest, however, it has no way of performing atomic, key checked, accesses to the guest. Extend the MEM_OP ioctl in order to allow for this, by adding a cmpxchg operation. For now, support this operation for absolute accesses only. This operation can be use, for example, to set the device-state-change indicator and the adapter-local-summary indicator atomically. Also contains some fixes/changes for the memop selftest independent of the cmpxchg changes. v5 -> v6 * move memop selftest fixes/refactoring to front of series so they can be picked independently from the rest * use op instead of flag to indicate cmpxchg * no longer indicate success of cmpxchg to user space, which can infer it by observing a change in the old value instead * refactor functions implementing the ioctl * adjust documentation (drop R-b) * adjust selftest * rebase v4 -> v5 * refuse cmpxchg if not write (thanks Thomas) * minor doc changes (thanks Claudio) * picked up R-b's (thanks Thomas & Claudio) * memop selftest fixes * rebased v3 -> v4 * no functional change intended * rework documentation a bit * name extension cap cmpxchg bit * picked up R-b (thanks Thomas) * various changes (rename variable, comments, ...) see range-diff below v2 -> v3 * rebase onto the wip/cmpxchg_user_key branch in the s390 kernel repo * use __uint128_t instead of unsigned __int128 * put moving of testlist into main into separate patch * pick up R-b's (thanks Nico) v1 -> v2 * get rid of xrk instruction for cmpxchg byte and short implementation * pass old parameter via pointer instead of in mem_op struct * indicate failure of cmpxchg due to wrong old value by special return code * picked up R-b's (thanks Thomas) Janis Schoetterl-Glausch (14): KVM: s390: selftest: memop: Pass mop_desc via pointer KVM: s390: selftest: memop: Replace macros by functions KVM: s390: selftest: memop: Move testlist into main KVM: s390: selftest: memop: Add bad address test KVM: s390: selftest: memop: Fix typo KVM: s390: selftest: memop: Fix wrong address being used in test KVM: s390: selftest: memop: Fix integer literal KVM: s390: Move common code of mem_op functions into functions KVM: s390: Dispatch to implementing function at top level of vm mem_op KVM: s390: Refactor absolute vm mem_op function KVM: s390: Refactor absolute vcpu mem_op function KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg Documentation: KVM: s390: Describe KVM_S390_MEMOP_F_CMPXCHG KVM: s390: selftest: memop: Add cmpxchg tests Documentation/virt/kvm/api.rst | 29 +- include/uapi/linux/kvm.h | 8 + arch/s390/kvm/gaccess.h | 3 + arch/s390/kvm/gaccess.c | 103 ++++ arch/s390/kvm/kvm-s390.c | 249 ++++---- tools/testing/selftests/kvm/s390x/memop.c | 675 +++++++++++++++++----- 6 files changed, 819 insertions(+), 248 deletions(-) Range-diff against v5: 3: 94c1165ae24a = 1: 512e1a3e0ae5 KVM: s390: selftest: memop: Pass mop_desc via pointer 4: 027c87eee0ac = 2: 47328ea64f80 KVM: s390: selftest: memop: Replace macros by functions 5: 16ac410ecc0f = 3: 224fe37eeec7 KVM: s390: selftest: memop: Move testlist into main 7: 2d6776733e64 = 4: f622d3413cf0 KVM: s390: selftest: memop: Add bad address test 8: 8c49eafd2881 = 5: 431f191a8a57 KVM: s390: selftest: memop: Fix typo 9: 0af907110b34 = 6: 3122187435fb KVM: s390: selftest: memop: Fix wrong address being used in test 10: 886c80b2bdce = 7: 401f51f3ef55 KVM: s390: selftest: memop: Fix integer literal -: ------------ > 8: df09794e0794 KVM: s390: Move common code of mem_op functions into functions -: ------------ > 9: 5cbae63357ed KVM: s390: Dispatch to implementing function at top level of vm mem_op -: ------------ > 10: 76ba77b63a26 KVM: s390: Refactor absolute vm mem_op function -: ------------ > 11: c848e772e22a KVM: s390: Refactor absolute vcpu mem_op function 1: 6adc166ee141 ! 12: 6ccb200ad85c KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg @@ Commit message and writes to the guest, however, it has no way of performing atomic, key checked, accesses to the guest. Extend the MEM_OP ioctl in order to allow for this, by adding a cmpxchg - mode. For now, support this mode for absolute accesses only. + op. For now, support this op for absolute accesses only. - This mode can be use, for example, to set the device-state-change + This op can be use, for example, to set the device-state-change indicator and the adapter-local-summary indicator atomically. Signed-off-by: Janis Schoetterl-Glausch @@ include/uapi/linux/kvm.h: struct kvm_s390_mem_op { __u8 ar; /* the access register number */ __u8 key; /* access key, ignored if flag unset */ + __u8 pad1[6]; /* ignored */ -+ __u64 old_addr; /* ignored if flag unset */ ++ __u64 old_addr; /* ignored if cmpxchg flag unset */ }; __u32 sida_offset; /* offset into the sida */ __u8 reserved[32]; /* ignored */ @@ include/uapi/linux/kvm.h: struct kvm_s390_mem_op { + #define KVM_S390_MEMOP_SIDA_WRITE 3 + #define KVM_S390_MEMOP_ABSOLUTE_READ 4 + #define KVM_S390_MEMOP_ABSOLUTE_WRITE 5 ++#define KVM_S390_MEMOP_ABSOLUTE_CMPXCHG 6 ++ + /* flags for kvm_s390_mem_op->flags */ #define KVM_S390_MEMOP_F_CHECK_ONLY (1ULL << 0) #define KVM_S390_MEMOP_F_INJECT_EXCEPTION (1ULL << 1) #define KVM_S390_MEMOP_F_SKEY_PROTECTION (1ULL << 2) -+#define KVM_S390_MEMOP_F_CMPXCHG (1ULL << 3) -+/* flags specifying extension support */ -+#define KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG 0x2 -+/* Non program exception return codes (pgm codes are 16 bit) */ -+#define KVM_S390_MEMOP_R_NO_XCHG (1 << 16) ++/* flags specifying extension support via KVM_CAP_S390_MEM_OP_EXTENSION */ ++#define KVM_S390_MEMOP_EXTENSION_CAP_BASE (1 << 0) ++#define KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG (1 << 1) ++ /* for KVM_INTERRUPT */ struct kvm_interrupt { + /* in */ ## arch/s390/kvm/gaccess.h ## @@ arch/s390/kvm/gaccess.h: int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, unsigned long len, enum gacc_mode mode); -+int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, -+ __uint128_t *old, __uint128_t new, u8 access_key); ++int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, __uint128_t *old, ++ __uint128_t new, u8 access_key, bool *success); + /** * write_guest_with_key - copy data from kernel space to guest space @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + * @gpa: Absolute guest address of the location to be changed. + * @len: Operand length of the cmpxchg, required: 1 <= len <= 16. Providing a + * non power of two will result in failure. -+ * @old_addr: Pointer to old value. If the location at @gpa contains this value, the -+ * exchange will succeed. After calling cmpxchg_guest_abs_with_key() *@old -+ * contains the value at @gpa before the attempt to exchange the value. ++ * @old_addr: Pointer to old value. If the location at @gpa contains this value, ++ * the exchange will succeed. After calling cmpxchg_guest_abs_with_key() ++ * *@old_addr contains the value at @gpa before the attempt to ++ * exchange the value. + * @new: The value to place at @gpa. + * @access_key: The access key to use for the guest access. ++ * @success: output value indicating if an exchange occurred. + * + * Atomically exchange the value at @gpa by @new, if it contains *@old. + * Honors storage keys. + * + * Return: * 0: successful exchange -+ * * 1: exchange unsuccessful + * * a program interruption code indicating the reason cmpxchg could + * not be attempted + * * -EINVAL: address misaligned or len not power of two @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + */ +int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, + __uint128_t *old_addr, __uint128_t new, -+ u8 access_key) ++ u8 access_key, bool *success) +{ + gfn_t gfn = gpa >> PAGE_SHIFT; + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn); @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + u8 old; + + ret = cmpxchg_user_key((u8 *)hva, &old, *old_addr, new, access_key); -+ ret = ret < 0 ? ret : old != *old_addr; ++ *success = !ret && old == *old_addr; + *old_addr = old; + break; + } @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + u16 old; + + ret = cmpxchg_user_key((u16 *)hva, &old, *old_addr, new, access_key); -+ ret = ret < 0 ? ret : old != *old_addr; ++ *success = !ret && old == *old_addr; + *old_addr = old; + break; + } @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + u32 old; + + ret = cmpxchg_user_key((u32 *)hva, &old, *old_addr, new, access_key); -+ ret = ret < 0 ? ret : old != *old_addr; ++ *success = !ret && old == *old_addr; + *old_addr = old; + break; + } @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + u64 old; + + ret = cmpxchg_user_key((u64 *)hva, &old, *old_addr, new, access_key); -+ ret = ret < 0 ? ret : old != *old_addr; ++ *success = !ret && old == *old_addr; + *old_addr = old; + break; + } @@ arch/s390/kvm/gaccess.c: int access_guest_real(struct kvm_vcpu *vcpu, unsigned l + __uint128_t old; + + ret = cmpxchg_user_key((__uint128_t *)hva, &old, *old_addr, new, access_key); -+ ret = ret < 0 ? ret : old != *old_addr; ++ *success = !ret && old == *old_addr; + *old_addr = old; + break; + } @@ arch/s390/kvm/kvm-s390.c: int kvm_vm_ioctl_check_extension(struct kvm *kvm, long + case KVM_CAP_S390_MEM_OP_EXTENSION: + /* + * Flag bits indicating which extensions are supported. -+ * The first extension doesn't use a flag, but pretend it does, -+ * this way that can be changed in the future. ++ * If r > 0, the base extension must also be supported/indicated, ++ * in order to maintain backwards compatibility. + */ -+ r = KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG | 1; ++ r = KVM_S390_MEMOP_EXTENSION_CAP_BASE | ++ KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG; + break; case KVM_CAP_NR_VCPUS: case KVM_CAP_MAX_VCPUS: case KVM_CAP_MAX_VCPU_ID: -@@ arch/s390/kvm/kvm-s390.c: static bool access_key_invalid(u8 access_key) - static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) - { - void __user *uaddr = (void __user *)mop->buf; +@@ arch/s390/kvm/kvm-s390.c: static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op *mop) + return r; + } + ++static int kvm_s390_vm_mem_op_cmpxchg(struct kvm *kvm, struct kvm_s390_mem_op *mop) ++{ ++ void __user *uaddr = (void __user *)mop->buf; + void __user *old_addr = (void __user *)mop->old_addr; + union { + __uint128_t quad; + char raw[sizeof(__uint128_t)]; + } old = { .quad = 0}, new = { .quad = 0 }; + unsigned int off_in_quad = sizeof(new) - mop->size; - u64 supported_flags; - void *tmpbuf = NULL; - int r, srcu_idx; - - supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION -- | KVM_S390_MEMOP_F_CHECK_ONLY; -+ | KVM_S390_MEMOP_F_CHECK_ONLY -+ | KVM_S390_MEMOP_F_CMPXCHG; - if (mop->flags & ~supported_flags || !mop->size) - return -EINVAL; - if (mop->size > MEM_OP_MAX_SIZE) -@@ arch/s390/kvm/kvm-s390.c: static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) - } else { - mop->key = 0; - } -+ if (mop->flags & KVM_S390_MEMOP_F_CMPXCHG) { -+ /* -+ * This validates off_in_quad. Checking that size is a power -+ * of two is not necessary, as cmpxchg_guest_abs_with_key -+ * takes care of that -+ */ -+ if (mop->size > sizeof(new)) -+ return -EINVAL; -+ if (mop->op != KVM_S390_MEMOP_ABSOLUTE_WRITE) -+ return -EINVAL; -+ if (copy_from_user(&new.raw[off_in_quad], uaddr, mop->size)) -+ return -EFAULT; -+ if (copy_from_user(&old.raw[off_in_quad], old_addr, mop->size)) -+ return -EFAULT; ++ int r, srcu_idx; ++ bool success; ++ ++ r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION); ++ if (r) ++ return r; ++ /* ++ * This validates off_in_quad. Checking that size is a power ++ * of two is not necessary, as cmpxchg_guest_abs_with_key ++ * takes care of that ++ */ ++ if (mop->size > sizeof(new)) ++ return -EINVAL; ++ if (copy_from_user(&new.raw[off_in_quad], uaddr, mop->size)) ++ return -EFAULT; ++ if (copy_from_user(&old.raw[off_in_quad], old_addr, mop->size)) ++ return -EFAULT; ++ ++ srcu_idx = srcu_read_lock(&kvm->srcu); ++ ++ if (kvm_is_error_gpa(kvm, mop->gaddr)) { ++ r = PGM_ADDRESSING; ++ goto out_unlock; + } - if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) { - tmpbuf = vmalloc(mop->size); - if (!tmpbuf) ++ ++ r = cmpxchg_guest_abs_with_key(kvm, mop->gaddr, mop->size, &old.quad, ++ new.quad, mop->key, &success); ++ if (!success && copy_to_user(old_addr, &old.raw[off_in_quad], mop->size)) ++ r = -EFAULT; ++ ++out_unlock: ++ srcu_read_unlock(&kvm->srcu, srcu_idx); ++ return r; ++} ++ + static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) + { + /* @@ arch/s390/kvm/kvm-s390.c: static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop) - case KVM_S390_MEMOP_ABSOLUTE_WRITE: { - if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) { - r = check_gpa_range(kvm, mop->gaddr, mop->size, GACC_STORE, mop->key); -+ } else if (mop->flags & KVM_S390_MEMOP_F_CMPXCHG) { -+ r = cmpxchg_guest_abs_with_key(kvm, mop->gaddr, mop->size, -+ &old.quad, new.quad, mop->key); -+ if (r == 1) { -+ r = KVM_S390_MEMOP_R_NO_XCHG; -+ if (copy_to_user(old_addr, &old.raw[off_in_quad], mop->size)) -+ r = -EFAULT; -+ } - } else { - if (copy_from_user(tmpbuf, uaddr, mop->size)) { - r = -EFAULT; + case KVM_S390_MEMOP_ABSOLUTE_READ: + case KVM_S390_MEMOP_ABSOLUTE_WRITE: + return kvm_s390_vm_mem_op_abs(kvm, mop); ++ case KVM_S390_MEMOP_ABSOLUTE_CMPXCHG: ++ return kvm_s390_vm_mem_op_cmpxchg(kvm, mop); + default: + return -EINVAL; + } 2: fce9a063ab70 ! 13: 4d983d179903 Documentation: KVM: s390: Describe KVM_S390_MEMOP_F_CMPXCHG @@ Commit message checked) cmpxchg operations on guest memory. Signed-off-by: Janis Schoetterl-Glausch - Reviewed-by: Claudio Imbrenda ## Documentation/virt/kvm/api.rst ## @@ Documentation/virt/kvm/api.rst: The fields in each entry are defined as follows: @@ Documentation/virt/kvm/api.rst: Parameters are specified via the following struc }; __u32 sida_offset; /* offset into the sida */ __u8 reserved[32]; /* ignored */ -@@ Documentation/virt/kvm/api.rst: Absolute accesses are permitted for non-protected guests only. - Supported flags: +@@ Documentation/virt/kvm/api.rst: Possible operations are: + * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` + * ``KVM_S390_MEMOP_SIDA_READ`` + * ``KVM_S390_MEMOP_SIDA_WRITE`` ++ * ``KVM_S390_MEMOP_ABSOLUTE_CMPXCHG`` + + Logical read/write: + ^^^^^^^^^^^^^^^^^^^ +@@ Documentation/virt/kvm/api.rst: the checks required for storage key protection as one operation (as opposed to + user space getting the storage keys, performing the checks, and accessing + memory thereafter, which could lead to a delay between check and access). + Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION +-is > 0. ++has the KVM_S390_MEMOP_EXTENSION_CAP_BASE bit set. + Currently absolute accesses are not permitted for VCPU ioctls. + Absolute accesses are permitted for non-protected guests only. + +@@ Documentation/virt/kvm/api.rst: Supported flags: * ``KVM_S390_MEMOP_F_CHECK_ONLY`` * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` -+ * ``KVM_S390_MEMOP_F_CMPXCHG`` -+ + +-The semantics of the flags are as for logical accesses. +The semantics of the flags common with logical accesses are as for logical +accesses. + -+For write accesses, the KVM_S390_MEMOP_F_CMPXCHG flag is supported if -+KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set. -+In this case, instead of doing an unconditional write, the access occurs -+only if the target location contains the value pointed to by "old_addr". ++Absolute cmpxchg: ++^^^^^^^^^^^^^^^^^ ++ ++Perform cmpxchg on absolute guest memory. Intended for use with the ++KVM_S390_MEMOP_F_SKEY_PROTECTION flag. ++Instead of doing an unconditional write, the access occurs only if the target ++location contains the value pointed to by "old_addr". +This is performed as an atomic cmpxchg with the length specified by the "size" +parameter. "size" must be a power of two up to and including 16. +If the exchange did not take place because the target value doesn't match the -+old value, KVM_S390_MEMOP_R_NO_XCHG is returned. -+In this case the value "old_addr" points to is replaced by the target value. - --The semantics of the flags are as for logical accesses. ++old value, the value "old_addr" points to is replaced by the target value. ++User space can tell if an exchange took place by checking if this replacement ++occurred. The cmpxchg op is permitted for the VM ioctl if ++KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set. ++ ++Supported flags: ++ * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` SIDA read/write: ^^^^^^^^^^^^^^^^ 6: 214281b6eb96 ! 14: 5250be3dd58b KVM: s390: selftest: memop: Add cmpxchg tests @@ tools/testing/selftests/kvm/s390x/memop.c #include +@@ tools/testing/selftests/kvm/s390x/memop.c: enum mop_target { + enum mop_access_mode { + READ, + WRITE, ++ CMPXCHG, + }; + + struct mop_desc { @@ tools/testing/selftests/kvm/s390x/memop.c: struct mop_desc { enum mop_access_mode mode; void *buf; uint32_t sida_offset; + void *old; ++ uint8_t old_value[16]; + bool *cmpxchg_success; uint8_t ar; uint8_t key; }; + + const uint8_t NO_KEY = 0xff; + +-static struct kvm_s390_mem_op ksmo_from_desc(const struct mop_desc *desc) ++static struct kvm_s390_mem_op ksmo_from_desc(struct mop_desc *desc) + { + struct kvm_s390_mem_op ksmo = { + .gaddr = (uintptr_t)desc->gaddr, @@ tools/testing/selftests/kvm/s390x/memop.c: static struct kvm_s390_mem_op ksmo_from_desc(const struct mop_desc *desc) - ksmo.flags |= KVM_S390_MEMOP_F_SKEY_PROTECTION; - ksmo.key = desc->key; - } -+ if (desc->old) { -+ ksmo.flags |= KVM_S390_MEMOP_F_CMPXCHG; -+ ksmo.old_addr = (uint64_t)desc->old; -+ } - if (desc->_ar) - ksmo.ar = desc->ar; - else + ksmo.op = KVM_S390_MEMOP_ABSOLUTE_READ; + if (desc->mode == WRITE) + ksmo.op = KVM_S390_MEMOP_ABSOLUTE_WRITE; ++ if (desc->mode == CMPXCHG) { ++ ksmo.op = KVM_S390_MEMOP_ABSOLUTE_CMPXCHG; ++ ksmo.old_addr = (uint64_t)desc->old; ++ memcpy(desc->old_value, desc->old, desc->size); ++ } + break; + case INVALID: + ksmo.op = -1; @@ tools/testing/selftests/kvm/s390x/memop.c: static void print_memop(struct kvm_vcpu *vcpu, const struct kvm_s390_mem_op *ksm + case KVM_S390_MEMOP_ABSOLUTE_WRITE: printf("ABSOLUTE, WRITE, "); break; ++ case KVM_S390_MEMOP_ABSOLUTE_CMPXCHG: ++ printf("ABSOLUTE, CMPXCHG, "); ++ break; } - printf("gaddr=%llu, size=%u, buf=%llu, ar=%u, key=%u", - ksmo->gaddr, ksmo->size, ksmo->buf, ksmo->ar, ksmo->key); @@ tools/testing/selftests/kvm/s390x/memop.c: static void print_memop(struct kvm_vc if (ksmo->flags & KVM_S390_MEMOP_F_CHECK_ONLY) printf(", CHECK_ONLY"); if (ksmo->flags & KVM_S390_MEMOP_F_INJECT_EXCEPTION) - printf(", INJECT_EXCEPTION"); - if (ksmo->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) - printf(", SKEY_PROTECTION"); -+ if (ksmo->flags & KVM_S390_MEMOP_F_CMPXCHG) -+ printf(", CMPXCHG"); +@@ tools/testing/selftests/kvm/s390x/memop.c: static void print_memop(struct kvm_vcpu *vcpu, const struct kvm_s390_mem_op *ksm puts(")"); } @@ tools/testing/selftests/kvm/s390x/memop.c: static void print_memop(struct kvm_vc + int r; + + r = err_memop_ioctl(info, ksmo, desc); -+ if (ksmo->flags & KVM_S390_MEMOP_F_CMPXCHG) { -+ if (desc->cmpxchg_success) -+ *desc->cmpxchg_success = !r; -+ if (r == KVM_S390_MEMOP_R_NO_XCHG) -+ r = 0; ++ if (ksmo->op == KVM_S390_MEMOP_ABSOLUTE_CMPXCHG) { ++ if (desc->cmpxchg_success) { ++ int diff = memcmp(desc->old_value, desc->old, desc->size); ++ *desc->cmpxchg_success = !diff; ++ } + } + TEST_ASSERT(!r, __KVM_IOCTL_ERROR("KVM_S390_MEM_OP", r)); @@ tools/testing/selftests/kvm/s390x/memop.c: static void default_read(struct test_ + default_write_read(test->vcpu, test->vcpu, LOGICAL, 16, NO_KEY); + + memcpy(&old, mem1, 16); -+ CHECK_N_DO(MOP, test->vm, ABSOLUTE, WRITE, new + offset, -+ size, GADDR_V(mem1 + offset), -+ CMPXCHG_OLD(old + offset), -+ CMPXCHG_SUCCESS(&succ), KEY(key)); ++ MOP(test->vm, ABSOLUTE, CMPXCHG, new + offset, ++ size, GADDR_V(mem1 + offset), ++ CMPXCHG_OLD(old + offset), ++ CMPXCHG_SUCCESS(&succ), KEY(key)); + HOST_SYNC(test->vcpu, STAGE_COPIED); + MOP(test->vm, ABSOLUTE, READ, mem2, 16, GADDR_V(mem2)); + TEST_ASSERT(succ, "exchange of values should succeed"); @@ tools/testing/selftests/kvm/s390x/memop.c: static void default_read(struct test_ + memcpy(&old, mem1, 16); + new[offset]++; + old[offset]++; -+ CHECK_N_DO(MOP, test->vm, ABSOLUTE, WRITE, new + offset, -+ size, GADDR_V(mem1 + offset), -+ CMPXCHG_OLD(old + offset), -+ CMPXCHG_SUCCESS(&succ), KEY(key)); ++ MOP(test->vm, ABSOLUTE, CMPXCHG, new + offset, ++ size, GADDR_V(mem1 + offset), ++ CMPXCHG_OLD(old + offset), ++ CMPXCHG_SUCCESS(&succ), KEY(key)); + HOST_SYNC(test->vcpu, STAGE_COPIED); + MOP(test->vm, ABSOLUTE, READ, mem2, 16, GADDR_V(mem2)); + TEST_ASSERT(!succ, "exchange of values should not succeed"); @@ tools/testing/selftests/kvm/s390x/memop.c: static void test_copy_key(void) + do { + old = 0; + new = 1; -+ MOP(t.vm, ABSOLUTE, WRITE, &new, ++ MOP(t.vm, ABSOLUTE, CMPXCHG, &new, + sizeof(new), GADDR_V(mem1), + CMPXCHG_OLD(&old), + CMPXCHG_SUCCESS(&success), KEY(1)); @@ tools/testing/selftests/kvm/s390x/memop.c: static void test_copy_key(void) + choose_block(false, i + j, &size, &offset); + do { + new = permutate_bits(false, i + j, size, old); -+ MOP(t.vm, ABSOLUTE, WRITE, quad_to_char(&new, size), ++ MOP(t.vm, ABSOLUTE, CMPXCHG, quad_to_char(&new, size), + size, GADDR_V(mem2 + offset), + CMPXCHG_OLD(quad_to_char(&old, size)), + CMPXCHG_SUCCESS(&success), KEY(1)); @@ tools/testing/selftests/kvm/s390x/memop.c: static void test_errors_key(void) + for (i = 1; i <= 16; i *= 2) { + __uint128_t old = 0; + -+ CHECK_N_DO(ERR_PROT_MOP, t.vm, ABSOLUTE, WRITE, mem2, i, GADDR_V(mem2), -+ CMPXCHG_OLD(&old), KEY(2)); ++ ERR_PROT_MOP(t.vm, ABSOLUTE, CMPXCHG, mem2, i, GADDR_V(mem2), ++ CMPXCHG_OLD(&old), KEY(2)); + } + + kvm_vm_free(t.kvm_vm); @@ tools/testing/selftests/kvm/s390x/memop.c: static void test_errors(void) + power *= 2; + continue; + } -+ rv = ERR_MOP(t.vm, ABSOLUTE, WRITE, mem1, i, GADDR_V(mem1), ++ rv = ERR_MOP(t.vm, ABSOLUTE, CMPXCHG, mem1, i, GADDR_V(mem1), + CMPXCHG_OLD(&old)); + TEST_ASSERT(rv == -1 && errno == EINVAL, + "ioctl allows bad size for cmpxchg"); + } + for (i = 1; i <= 16; i *= 2) { -+ rv = ERR_MOP(t.vm, ABSOLUTE, WRITE, mem1, i, GADDR((void *)~0xfffUL), ++ rv = ERR_MOP(t.vm, ABSOLUTE, CMPXCHG, mem1, i, GADDR((void *)~0xfffUL), + CMPXCHG_OLD(&old)); + TEST_ASSERT(rv > 0, "ioctl allows bad guest address for cmpxchg"); -+ rv = ERR_MOP(t.vm, ABSOLUTE, READ, mem1, i, GADDR_V(mem1), -+ CMPXCHG_OLD(&old)); -+ TEST_ASSERT(rv == -1 && errno == EINVAL, -+ "ioctl allows read cmpxchg call"); + } + for (i = 2; i <= 16; i *= 2) { -+ rv = ERR_MOP(t.vm, ABSOLUTE, WRITE, mem1, i, GADDR_V(mem1 + 1), ++ rv = ERR_MOP(t.vm, ABSOLUTE, CMPXCHG, mem1, i, GADDR_V(mem1 + 1), + CMPXCHG_OLD(&old)); + TEST_ASSERT(rv == -1 && errno == EINVAL, + "ioctl allows bad alignment for cmpxchg");