From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v6 1/7] s390: ap: kvm: add PQAP interception for AQIC Date: Fri, 29 Mar 2019 09:52:06 +0100 Message-ID: References: <1553265828-27823-1-git-send-email-pmorel@linux.ibm.com> <1553265828-27823-2-git-send-email-pmorel@linux.ibm.com> <32716ed4-559f-0c36-cdf3-4c6662e02f4b@linux.ibm.com> Reply-To: pmorel@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <32716ed4-559f-0c36-cdf3-4c6662e02f4b@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Tony Krowiak , borntraeger@de.ibm.com Cc: alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com List-ID: On 28/03/2019 17:12, Tony Krowiak wrote: > On 3/22/19 10:43 AM, Pierre Morel wrote: >> We prepare the interception of the PQAP/AQIC instruction for >> the case the AQIC facility is enabled in the guest. >> >> First of all we do not want to change existing behavior when >> intercepting AP instructions without the SIE allowing the guest >> to use AP instructions. >> >> In this patch we only handle the AQIC interception allowed by >> facility 65 which will be enabled when the complete interception >> infrastructure will be present. >> >> We add a callback inside the KVM arch structure for s390 for >> a VFIO driver to handle a specific response to the PQAP >> instruction with the AQIC command and only this command. >> >> But we want to be able to return a correct answer to the guest >> even there is no VFIO AP driver in the kernel. >> Therefor, we inject the correct exceptions from inside KVM for the >> case the callback is not initialized, which happens when the vfio_ap >> driver is not loaded. >> >> We do consider the responsability of the driver to always initialize >> the PQAP callback if it defines queues by initializing the CRYCB for >> a guest. >> If the callback has been setup we call it. >> If not we setup an answer considering that no queue is available >> for the guest when no callback has been setup. >> >> Signed-off-by: Pierre Morel >> --- >>   arch/s390/include/asm/kvm_host.h      |  8 ++++ >>   arch/s390/kvm/priv.c                  | 90 >> +++++++++++++++++++++++++++++++++++ >>   drivers/s390/crypto/vfio_ap_private.h |  2 + >>   3 files changed, 100 insertions(+) >> >> diff --git a/arch/s390/include/asm/kvm_host.h >> b/arch/s390/include/asm/kvm_host.h >> index a496276..624460b 100644 >> --- a/arch/s390/include/asm/kvm_host.h >> +++ b/arch/s390/include/asm/kvm_host.h >> @@ -18,6 +18,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include >>   #include >>   #include >> @@ -721,8 +722,15 @@ struct kvm_s390_cpu_model { >>       unsigned short ibc; >>   }; >> +struct kvm_s390_module_hook { >> +    int (*hook)(struct kvm_vcpu *vcpu); >> +    void *data; >> +    struct module *owner; >> +}; >> + >>   struct kvm_s390_crypto { >>       struct kvm_s390_crypto_cb *crycb; >> +    struct kvm_s390_module_hook *pqap_hook; >>       __u32 crycbd; >>       __u8 aes_kw; >>       __u8 dea_kw; >> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c >> index 8679bd7..793e48a 100644 >> --- a/arch/s390/kvm/priv.c >> +++ b/arch/s390/kvm/priv.c >> @@ -27,6 +27,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include "gaccess.h" >>   #include "kvm-s390.h" >>   #include "trace.h" >> @@ -592,6 +593,93 @@ static int handle_io_inst(struct kvm_vcpu *vcpu) >>       } >>   } >> +/* >> + * handle_pqap: Handling pqap interception >> + * @vcpu: the vcpu having issue the pqap instruction >> + * >> + * We now support PQAP/AQIC instructions and we need to correctly >> + * answer the guest even if no dedicated driver's hook is available. >> + * >> + * The intercepting code calls a dedicated callback for this instruction >> + * if a driver did register one in the CRYPTO satellite of the >> + * SIE block. >> + * >> + * For PQAP AQIC and TAPQ instructions, verify privilege and >> specifications. >> + * >> + * If no callback available, the queues are not available, return >> this to >> + * the caller. >> + * Else return the value returned by the callback. >> + */ >> +static int handle_pqap(struct kvm_vcpu *vcpu) >> +{ >> +    struct ap_queue_status status = {}; >> +    unsigned long reg0; >> +    int ret; >> +    uint8_t fc; >> + >> +    /* Verify that the AP instruction are available */ >> +    if (!ap_instructions_available()) >> +        return -EOPNOTSUPP; >> +    /* Verify that the guest is allowed to use AP instructions */ >> +    if (!(vcpu->arch.sie_block->eca & ECA_APIE)) >> +        return -EOPNOTSUPP; >> +    /* >> +     * The only possibly intercepted instructions when AP >> instructions are >> +     * available for the guest are AQIC and TAPQ with the t bit set >> +     * since we do not set IC.3 (FIII) we currently will not intercept >> +     * TAPQ. >> +     * The following code will only treat AQIC function code. >> +     */ >> +    reg0 = vcpu->run->s.regs.gprs[0]; >> +    fc = reg0 >> 24; >> +    if (fc != 0x03) { >> +        pr_warn("%s: Unexpected interception code 0x%02x\n", >> +            __func__, fc); >> +        return -EOPNOTSUPP; >> +    } >> +    /* All PQAP instructions are allowed for guest kernel only */ >> +    if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) >> +        return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); >> +    /* >> +     * Common tests for PQAP instructions to generate a specification >> +     * exception >> +     */ >> +    /* Zero bits overwrite produce a specification exception */ >> +    if (reg0 & 0x007f0000UL) >> +        goto specification_except; >> +    /* If APXA is not installed APQN is limited */ >> +    if (!(vcpu->kvm->arch.crypto.crycbd & 0x02)) >> +        if (reg0 & 0x000030f0UL) >> +            goto specification_except; >> +    /* AQIC needs facility 65 */ >> +    if (!test_kvm_facility(vcpu->kvm, 65)) >> +        goto specification_except; >> + >> +    /* >> +     * Verify that the hook callback is registered, lock the owner >> +     * and call the hook. >> +     */ >> +    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); >> +        return ret; >> +    } >> +    /* >> +     * It is the duty of the vfio_driver to register a hook >> +     * If it does not and we get an exception on AQIC we must >> +     * guess that there is no vfio_ap_driver at all and no one >> +     * to handle the guests's CRYCB and the CRYCB is empty. >> +     */ >> +    status.response_code = 0x01; >> +    memcpy(&vcpu->run->s.regs.gprs[1], &status, sizeof(status)); >> +    return 0; >> + >> +specification_except: >> +    return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); >> +} >> + >>   static int handle_stfl(struct kvm_vcpu *vcpu) >>   { >>       int rc; >> @@ -878,6 +966,8 @@ int kvm_s390_handle_b2(struct kvm_vcpu *vcpu) >>           return handle_sthyi(vcpu); >>       case 0x7d: >>           return handle_stsi(vcpu); >> +    case 0xaf: >> +        return handle_pqap(vcpu); >>       case 0xb1: >>           return handle_stfl(vcpu); >>       case 0xb2: >> diff --git a/drivers/s390/crypto/vfio_ap_private.h >> b/drivers/s390/crypto/vfio_ap_private.h >> index 76b7f98..a910be1 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -16,6 +16,7 @@ >>   #include >>   #include >>   #include >> +#include >>   #include "ap_bus.h" >> @@ -81,6 +82,7 @@ struct ap_matrix_mdev { >>       struct ap_matrix matrix; >>       struct notifier_block group_notifier; >>       struct kvm *kvm; >> +    struct kvm_s390_module_hook pqap_hook; > > I don't understand the purpose of adding this field. We set up the > the kvm->arch.crypto.pqap_hook in the vfio_ap_mdev_set_kvm which is > also in this same file, why not just use a static struct > kvm_s390_module_hook and reuse it when setting up > kvm->arch.crypto.pqap_hook? It saves you from initializing it every > time an ap_matrix_mdev is created. Having this field embedded in the matrix_mdev allows to easily retrieve the matrix_mdev from the the hook. Thanks, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany