Messages in this thread | | | Subject | Re: [PATCH v3 2/9] s390: ap: kvm: setting a hook for PQAP instructions | From | Pierre Morel <> | Date | Mon, 18 Feb 2019 19:29:10 +0100 |
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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 <pmorel@linux.ibm.com> >> Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com> >> --- >> 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 <asm/io.h> >> #include <asm/ptrace.h> >> #include <asm/sclp.h> >> +#include <asm/ap.h> >> #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
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