diff options
| author | Tony Krowiak <akrowiak@linux.ibm.com> | 2021-08-24 00:20:46 +0300 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2021-08-24 21:14:05 +0300 |
| commit | 1e753732bda6dcf888ea0b90b2a91ac1c1a0bae9 (patch) | |
| tree | fe3e3ceaddddd778884646e03eca0ec224f5ee6c /arch/s390/kvm/priv.c | |
| parent | eb24c1007e6852e024dc33b0dd9617b8500a1291 (diff) | |
| download | linux-1e753732bda6dcf888ea0b90b2a91ac1c1a0bae9.tar.xz | |
s390/vfio-ap: r/w lock for PQAP interception handler function pointer
The function pointer to the interception handler for the PQAP instruction
can get changed during the interception process. Let's add a
semaphore to struct kvm_s390_crypto to control read/write access to the
function pointer contained therein.
The semaphore must be locked for write access by the vfio_ap device driver
when notified that the KVM pointer has been set or cleared. It must be
locked for read access by the interception framework when the PQAP
instruction is intercepted.
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210823212047.1476436-2-akrowiak@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'arch/s390/kvm/priv.c')
| -rw-r--r-- | arch/s390/kvm/priv.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 9928f785c677..53da4ceb16a3 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -610,6 +610,7 @@ static int handle_io_inst(struct kvm_vcpu *vcpu) static int handle_pqap(struct kvm_vcpu *vcpu) { struct ap_queue_status status = {}; + crypto_hook pqap_hook; unsigned long reg0; int ret; uint8_t fc; @@ -654,18 +655,20 @@ static int handle_pqap(struct kvm_vcpu *vcpu) return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); /* - * Verify that the hook callback is registered, lock the owner - * and call the hook. + * If the hook callback is registered, there will be a pointer to the + * hook function pointer in the kvm_s390_crypto structure. Lock the + * owner, retrieve the hook function pointer and call the hook. */ + down_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem); if (vcpu->kvm->arch.crypto.pqap_hook) { - if (!try_module_get(vcpu->kvm->arch.crypto.pqap_hook->owner)) - return -EOPNOTSUPP; - ret = vcpu->kvm->arch.crypto.pqap_hook->hook(vcpu); - module_put(vcpu->kvm->arch.crypto.pqap_hook->owner); + pqap_hook = *vcpu->kvm->arch.crypto.pqap_hook; + ret = pqap_hook(vcpu); if (!ret && vcpu->run->s.regs.gprs[1] & 0x00ff0000) kvm_s390_set_psw_cc(vcpu, 3); + up_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem); return ret; } + up_read(&vcpu->kvm->arch.crypto.pqap_hook_rwsem); /* * A vfio_driver must register a hook. * No hook means no driver to enable the SIE CRYCB and no queues. |