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Wed, 4 Feb 2026 15:03:06 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, nsg@linux.ibm.com, nrb@linux.ibm.com, seiden@linux.ibm.com, gra@linux.ibm.com, schlameuss@linux.ibm.com, hca@linux.ibm.com, svens@linux.ibm.com, agordeev@linux.ibm.com, gor@linux.ibm.com, david@kernel.org, gerald.schaefer@linux.ibm.com Subject: [PATCH v7 23/29] KVM: s390: Storage key functions refactoring Date: Wed, 4 Feb 2026 16:02:52 +0100 Message-ID: <20260204150259.60425-24-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260204150259.60425-1-imbrenda@linux.ibm.com> References: <20260204150259.60425-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjA0MDExMyBTYWx0ZWRfX8ya7OoAWG8Zn /WS8uIyOdKmUMDqDUfxTd1NZH+TnxTtkfPaW4p6uQWuaK9nK863v3xFZzrDGXP7O8aleRS8w/67 LbvGV7XmekAmlZ+aU9/nXOG1/QOXDa1F9/j9IoxhXn2IwSYWJyTRMrdWItO61kz0shStcjU/S5Q GN1KZBMlOnyvfo0Wc3cw/Ym/mU4wTZHPeo6HNoTgQO5lD9Lu5D8FoGwBIoMt+poPU1SG+YYHDMD 2Zzxdpi8RuC7rE57+ryFmDsjm3auev4o3AxxfDGzRgRIJV3e0ZMXdaAHwnA5BUus85dqzAd4e3G 4Z6I+dBCYoYm6H4q3o1UYNeC6GO+tT7w0xlBBY/IxmkPWK5IIcLRGbgasM8d7q2d/JMdw6/Jp+t Fvp5C59KvtUYIHRe0RFPThapkrmEyCGsJYUO4XWK397c3q5d5SIePyf44cvz5Uf0X5q5eZ8hJ3w oMI1ae54d8ESJ5LSn6Q== X-Proofpoint-GUID: dZ4qbL8XeosjKvpcrGH2_7nwFJjwudIt X-Proofpoint-ORIG-GUID: dZ4qbL8XeosjKvpcrGH2_7nwFJjwudIt X-Authority-Analysis: v=2.4 cv=LesxKzfi c=1 sm=1 tr=0 ts=69835fb0 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=HyGg85_KfVV_UHYI6-AA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-04_04,2026-02-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 spamscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 suspectscore=0 priorityscore=1501 phishscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2602040113 Content-Type: text/plain; charset="utf-8" Refactor some storage key functions to improve readability. Introduce helper functions that will be used in the next patches. Signed-off-by: Claudio Imbrenda --- arch/s390/kvm/gaccess.c | 38 +++++++++---------- arch/s390/kvm/gaccess.h | 4 +- arch/s390/kvm/kvm-s390.c | 80 +++++++++++++++------------------------- arch/s390/kvm/kvm-s390.h | 8 ++++ 4 files changed, 59 insertions(+), 71 deletions(-) diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 9df868bddf9a..2649365bf054 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -961,7 +961,7 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned l= ong gra, * *@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. + * @acc: 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. @@ -974,9 +974,8 @@ int access_guest_real(struct kvm_vcpu *vcpu, unsigned l= ong gra, * * -EAGAIN: transient failure (len 1 or 2) * * -EOPNOTSUPP: read-only memslot (should never occur) */ -int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, - __uint128_t *old_addr, __uint128_t new, - u8 access_key, bool *success) +int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, union = kvm_s390_quad *old_addr, + union kvm_s390_quad new, u8 acc, bool *success) { gfn_t gfn =3D gpa_to_gfn(gpa); struct kvm_memory_slot *slot =3D gfn_to_memslot(kvm, gfn); @@ -1008,41 +1007,42 @@ int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa= _t gpa, int len, case 1: { u8 old; =20 - ret =3D cmpxchg_user_key((u8 __user *)hva, &old, *old_addr, new, access_= key); - *success =3D !ret && old =3D=3D *old_addr; - *old_addr =3D old; + ret =3D cmpxchg_user_key((u8 __user *)hva, &old, old_addr->one, new.one,= acc); + *success =3D !ret && old =3D=3D old_addr->one; + old_addr->one =3D old; break; } case 2: { u16 old; =20 - ret =3D cmpxchg_user_key((u16 __user *)hva, &old, *old_addr, new, access= _key); - *success =3D !ret && old =3D=3D *old_addr; - *old_addr =3D old; + ret =3D cmpxchg_user_key((u16 __user *)hva, &old, old_addr->two, new.two= , acc); + *success =3D !ret && old =3D=3D old_addr->two; + old_addr->two =3D old; break; } case 4: { u32 old; =20 - ret =3D cmpxchg_user_key((u32 __user *)hva, &old, *old_addr, new, access= _key); - *success =3D !ret && old =3D=3D *old_addr; - *old_addr =3D old; + ret =3D cmpxchg_user_key((u32 __user *)hva, &old, old_addr->four, new.fo= ur, acc); + *success =3D !ret && old =3D=3D old_addr->four; + old_addr->four =3D old; break; } case 8: { u64 old; =20 - ret =3D cmpxchg_user_key((u64 __user *)hva, &old, *old_addr, new, access= _key); - *success =3D !ret && old =3D=3D *old_addr; - *old_addr =3D old; + ret =3D cmpxchg_user_key((u64 __user *)hva, &old, old_addr->eight, new.e= ight, acc); + *success =3D !ret && old =3D=3D old_addr->eight; + old_addr->eight =3D old; break; } case 16: { __uint128_t old; =20 - ret =3D cmpxchg_user_key((__uint128_t __user *)hva, &old, *old_addr, new= , access_key); - *success =3D !ret && old =3D=3D *old_addr; - *old_addr =3D old; + ret =3D cmpxchg_user_key((__uint128_t __user *)hva, &old, old_addr->sixt= een, + new.sixteen, acc); + *success =3D !ret && old =3D=3D old_addr->sixteen; + old_addr->sixteen =3D old; break; } default: diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h index 3fde45a151f2..774cdf19998f 100644 --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -206,8 +206,8 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsign= ed long ga, u8 ar, int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, unsigned long len, enum gacc_mode mode); =20 -int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, __uint= 128_t *old, - __uint128_t new, u8 access_key, bool *success); +int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len, union = kvm_s390_quad *old_addr, + union kvm_s390_quad new, u8 access_key, bool *success); =20 /** * write_guest_with_key - copy data from kernel space to guest space diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 2b5ecdc3814e..f5411e093fb5 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2900,9 +2900,9 @@ static int mem_op_validate_common(struct kvm_s390_mem= _op *mop, u64 supported_fla static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, struct kvm_s390_mem_op = *mop) { void __user *uaddr =3D (void __user *)mop->buf; + void *tmpbuf __free(kvfree) =3D NULL; enum gacc_mode acc_mode; - void *tmpbuf =3D NULL; - int r, srcu_idx; + int r; =20 r =3D mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION | KVM_S390_MEMOP_F_CHECK_ONLY); @@ -2915,52 +2915,36 @@ static int kvm_s390_vm_mem_op_abs(struct kvm *kvm, = struct kvm_s390_mem_op *mop) return -ENOMEM; } =20 - srcu_idx =3D srcu_read_lock(&kvm->srcu); + acc_mode =3D mop->op =3D=3D KVM_S390_MEMOP_ABSOLUTE_READ ? GACC_FETCH : G= ACC_STORE; =20 - if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) { - r =3D PGM_ADDRESSING; - goto out_unlock; - } + scoped_guard(srcu, &kvm->srcu) { + if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) + return PGM_ADDRESSING; =20 - acc_mode =3D mop->op =3D=3D KVM_S390_MEMOP_ABSOLUTE_READ ? GACC_FETCH : G= ACC_STORE; - if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) { - r =3D check_gpa_range(kvm, mop->gaddr, mop->size, acc_mode, mop->key); - goto out_unlock; - } - if (acc_mode =3D=3D GACC_FETCH) { + if (mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY) + return check_gpa_range(kvm, mop->gaddr, mop->size, acc_mode, mop->key); + + if (acc_mode =3D=3D GACC_STORE && copy_from_user(tmpbuf, uaddr, mop->siz= e)) + return -EFAULT; r =3D access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf, - mop->size, GACC_FETCH, mop->key); + mop->size, acc_mode, mop->key); if (r) - goto out_unlock; - if (copy_to_user(uaddr, tmpbuf, mop->size)) - r =3D -EFAULT; - } else { - if (copy_from_user(tmpbuf, uaddr, mop->size)) { - r =3D -EFAULT; - goto out_unlock; - } - r =3D access_guest_abs_with_key(kvm, mop->gaddr, tmpbuf, - mop->size, GACC_STORE, mop->key); + return r; + if (acc_mode !=3D GACC_STORE && copy_to_user(uaddr, tmpbuf, mop->size)) + return -EFAULT; } =20 -out_unlock: - srcu_read_unlock(&kvm->srcu, srcu_idx); - - vfree(tmpbuf); - return r; + return 0; } =20 static int kvm_s390_vm_mem_op_cmpxchg(struct kvm *kvm, struct kvm_s390_mem= _op *mop) { void __user *uaddr =3D (void __user *)mop->buf; void __user *old_addr =3D (void __user *)mop->old_addr; - union { - __uint128_t quad; - char raw[sizeof(__uint128_t)]; - } old =3D { .quad =3D 0}, new =3D { .quad =3D 0 }; - unsigned int off_in_quad =3D sizeof(new) - mop->size; - int r, srcu_idx; - bool success; + union kvm_s390_quad old =3D { .sixteen =3D 0 }; + union kvm_s390_quad new =3D { .sixteen =3D 0 }; + bool success =3D false; + int r; =20 r =3D mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION); if (r) @@ -2972,25 +2956,21 @@ static int kvm_s390_vm_mem_op_cmpxchg(struct kvm *k= vm, struct kvm_s390_mem_op *m */ if (mop->size > sizeof(new)) return -EINVAL; - if (copy_from_user(&new.raw[off_in_quad], uaddr, mop->size)) + if (copy_from_user(&new, uaddr, mop->size)) return -EFAULT; - if (copy_from_user(&old.raw[off_in_quad], old_addr, mop->size)) + if (copy_from_user(&old, old_addr, mop->size)) return -EFAULT; =20 - srcu_idx =3D srcu_read_lock(&kvm->srcu); + scoped_guard(srcu, &kvm->srcu) { + if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) + return PGM_ADDRESSING; =20 - if (!kvm_is_gpa_in_memslot(kvm, mop->gaddr)) { - r =3D PGM_ADDRESSING; - goto out_unlock; - } - - r =3D 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 =3D -EFAULT; + r =3D cmpxchg_guest_abs_with_key(kvm, mop->gaddr, mop->size, &old, new, + mop->key, &success); =20 -out_unlock: - srcu_read_unlock(&kvm->srcu, srcu_idx); + if (!success && copy_to_user(old_addr, &old, mop->size)) + return -EFAULT; + } return r; } =20 diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index 9ce71c8433a1..c44c52266e26 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -22,6 +22,14 @@ =20 #define KVM_S390_UCONTROL_MEMSLOT (KVM_USER_MEM_SLOTS + 0) =20 +union kvm_s390_quad { + __uint128_t sixteen; + unsigned long eight; + unsigned int four; + unsigned short two; + unsigned char one; +}; + static inline void kvm_s390_fpu_store(struct kvm_run *run) { fpu_stfpc(&run->s.regs.fpc); --=20 2.52.0