[PATCH v6 00/14] KVM: s390: Extend MEM_OP ioctl by storage key checked cmpxchg

Janis Schoetterl-Glausch
2023-01-25T21:26:44Z

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 <scgl@linux.ibm.com>
@@ 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 <scgl@linux.ibm.com>
- Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>

## 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 <linux/bits.h>

+@@ 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");
--
2.34.1