From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v3 2/9] s390: ap: kvm: setting a hook for PQAP instructions Date: Mon, 18 Feb 2019 19:29:10 +0100 Message-ID: References: <1550152269-6317-1-git-send-email-pmorel@linux.ibm.com> <1550152269-6317-3-git-send-email-pmorel@linux.ibm.com> <4b21f059-1d37-f341-bac7-5b1fe0d06521@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: <4b21f059-1d37-f341-bac7-5b1fe0d06521@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 15/02/2019 23:02, Tony Krowiak wrote: > On 2/14/19 8:51 AM, Pierre Morel wrote: >> This patch adds interception code for the PQAP instructions, >> and a callback inside the KVM arch structure for s390. >> >> If a VFIO-AP drivers needs to intercept PQAP/AQIC or PQAP/TAPQ >> instructions, the driver will initialize the callback inside >> the kvm_arch structure to be called when the interception of a >> PQAP instruction occurs. >> >> If the callback is not initialized, the code still returns >> -EOPNOTSUPP to let userland handle the instruction as it used to. >> >> Signed-off-by: Pierre Morel >> Reviewed-by: Tony Krowiak >> --- >>   arch/s390/include/asm/kvm_host.h |  1 + >>   arch/s390/kvm/priv.c             | 50 >> ++++++++++++++++++++++++++++++++++++++++ >>   2 files changed, 51 insertions(+) >> >> diff --git a/arch/s390/include/asm/kvm_host.h >> b/arch/s390/include/asm/kvm_host.h >> index c5f5156..49cc8b0 100644 >> --- a/arch/s390/include/asm/kvm_host.h >> +++ b/arch/s390/include/asm/kvm_host.h >> @@ -719,6 +719,7 @@ struct kvm_s390_cpu_model { >>   struct kvm_s390_crypto { >>       struct kvm_s390_crypto_cb *crycb; >> +    int (*pqap_hook)(struct kvm_vcpu *vcpu); >>       __u32 crycbd; >>       __u8 aes_kw; >>       __u8 dea_kw; >> diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c >> index 8679bd7..72fdc21 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 +593,53 @@ static int handle_io_inst(struct kvm_vcpu *vcpu) >>       } >>   } >> +/* >> + * handle_pqap: Handling pqap interception >> + * @vcpu: the vcpu having issue the pqap instruction >> + * >> + * This callback only handles PQAP/AQIC instruction and >> + * calls a dedicated callback for this instruction if >> + * a driver did register one in the CRYPTO satellite of the >> + * SIE block. >> + * >> + * Do not change the behavior if, return -EOPNOTSUPP if: >> + * - the hook is not used do not change the behavior. >> + * - AP instructions are not available or not available to the guest >> + * - the instruction is not PQAP with function code indicating >> + *   AQIC do not change the previous behavior. >> + * >> + * For PQAP/AQIC instruction, verify privilege and specifications >> + * >> + * return the value returned by the callback. >> + */ >> +static int handle_pqap(struct kvm_vcpu *vcpu) >> +{ >> +    uint8_t fc; >> + >> +    /* Verify that the hook callback is registered */ >> +    if (!vcpu->kvm->arch.crypto.pqap_hook) >> +        return -EOPNOTSUPP; >> +    /* 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; >> +    /* Verify that the function code is AQIC */ >> +    fc = vcpu->run->s.regs.gprs[0] >> 24; >> +    if (fc != 0x03) >> +        return -EOPNOTSUPP; > > This does not belong here. Function code 3 is one of 7 function codes > that can be sent with the PQAP instruction. This belongs in the PQAP > hook code. On one hand, effectively I would prefer to put the code in the VFIO driver code. On the other hand, doing this would lead to export the code for test_kvm_facility() and kvm_s390_inject_program_int() from the kvm-s390.h I choose not to export these functions from the KVM code. Would like opinion from KVM maintainers? > >> + >> +    /* PQAP instructions are allowed for guest kernel only */ >> +    if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) >> +        return kvm_s390_inject_program_intkvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); >> +    /* AQIC instruction is allowed only if facility 65 is available */ >> +    if (!test_kvm_facility(vcpu->kvm, 65)) >> +        return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); >> +    /* All right, call the callback */ >> +    return vcpu->kvm->arch.crypto.pqap_hook(vcpu); >> +} >> + >>   static int handle_stfl(struct kvm_vcpu *vcpu) >>   { >>       int rc; >> @@ -878,6 +926,8 @@ 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: >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany