From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v8 1/4] s390: ap: kvm: add PQAP interception for AQIC References: <1556818451-1806-1-git-send-email-pmorel@linux.ibm.com> <1556818451-1806-2-git-send-email-pmorel@linux.ibm.com> From: Pierre Morel Date: Wed, 8 May 2019 18:07:50 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 8bit Message-Id: Sender: kvm-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 08/05/2019 17:48, Tony Krowiak wrote: > On 5/2/19 1:34 PM, 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      |  7 +++ >>   arch/s390/kvm/priv.c                  | 86 >> +++++++++++++++++++++++++++++++++++ >>   drivers/s390/crypto/vfio_ap_private.h |  2 + >>   3 files changed, 95 insertions(+) >> >> diff --git a/arch/s390/include/asm/kvm_host.h >> b/arch/s390/include/asm/kvm_host.h >> index 9fff9ab..af10a11 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 >> @@ -722,8 +723,14 @@ struct kvm_s390_cpu_model { >>       unsigned short ibc; >>   }; >> +struct kvm_s390_module_hook { >> +    int (*hook)(struct kvm_vcpu *vcpu); >> +    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..a9be84f 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 +593,89 @@ 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. >> + * >> + * If no callback is available, the queues are not available, return >> this >> + * response code to the caller and set CC to 3. >> + * Else return the response code 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 functions 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 only intercept >> +     * the AQIC function code. >> +     */ >> +    reg0 = vcpu->run->s.regs.gprs[0]; >> +    fc = reg0 >> 24; > > Should you also mask off bits 0-32 in case they might not be zeroes? Yes I will. > > Other than this, r-b > Thanks, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany