| Date | Tue, 14 Dec 2021 18:04:01 +0100 | Subject | Re: [PATCH 24/32] KVM: s390: intercept the rpcit instruction | From | Pierre Morel <> |
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On 12/7/21 21:57, Matthew Rosato wrote: > For faster handling of PCI translation refreshes, intercept in KVM > and call the associated handler. > > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > arch/s390/kvm/pci.h | 4 ++++ > arch/s390/kvm/priv.c | 41 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 45 insertions(+) > > diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h > index d252a631b693..3f96eff432aa 100644 > --- a/arch/s390/kvm/pci.h > +++ b/arch/s390/kvm/pci.h > @@ -18,6 +18,10 @@ > > #define KVM_S390_PCI_DTSM_MASK 0x40 > > +#define KVM_S390_RPCIT_STAT_MASK 0xffffffff00ffffffUL > +#define KVM_S390_RPCIT_INS_RES (0x10 << 24) > +#define KVM_S390_RPCIT_ERR (0x28 << 24)
I
> + > struct zpci_gaite { > unsigned int gisa; > u8 gisc; > diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c > index 417154b314a6..768ae92ecc59 100644 > --- a/arch/s390/kvm/priv.c > +++ b/arch/s390/kvm/priv.c > @@ -29,6 +29,7 @@ > #include <asm/ap.h> > #include "gaccess.h" > #include "kvm-s390.h" > +#include "pci.h" > #include "trace.h" > > static int handle_ri(struct kvm_vcpu *vcpu) > @@ -335,6 +336,44 @@ static int handle_rrbe(struct kvm_vcpu *vcpu) > return 0; > } > > +static int handle_rpcit(struct kvm_vcpu *vcpu) > +{ > + int reg1, reg2; > + int rc; > + > + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) > + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); > + > + kvm_s390_get_regs_rre(vcpu, ®1, ®2); > +
I would prefer to take care of the interception immediately here
fh = vcpu->run->s.regs.gprs[reg1] >> 32; if ((fh & aift.mdd) != 0) return -EOPNOTSUP
instead of doing it inside kvm_s390_pci_refresh_trans. It would simplify in my opinion.
> + rc = kvm_s390_pci_refresh_trans(vcpu, vcpu->run->s.regs.gprs[reg1], > + vcpu->run->s.regs.gprs[reg2], > + vcpu->run->s.regs.gprs[reg2+1]); > +
> + switch (rc) { > + case 0: > + kvm_s390_set_psw_cc(vcpu, 0); > + break; > + case -EOPNOTSUPP: > + return -EOPNOTSUPP; > + case -EINVAL: > + kvm_s390_set_psw_cc(vcpu, 3); > + break; > + case -ENOMEM: > + vcpu->run->s.regs.gprs[reg1] &= KVM_S390_RPCIT_STAT_MASK; > + vcpu->run->s.regs.gprs[reg1] |= KVM_S390_RPCIT_INS_RES; > + kvm_s390_set_psw_cc(vcpu, 1); > + break; > + default: > + vcpu->run->s.regs.gprs[reg1] &= KVM_S390_RPCIT_STAT_MASK; > + vcpu->run->s.regs.gprs[reg1] |= KVM_S390_RPCIT_ERR;
I think you should use the status reported by the hardware, reporting "Error recovery in progress" what ever the hardware error was does not seem right.
> + kvm_s390_set_psw_cc(vcpu, 1); > + break; > + }
NIT: This switch above could be much more simple if you set CC after the switch.
> + > + return 0; > +} > + > #define SSKE_NQ 0x8 > #define SSKE_MR 0x4 > #define SSKE_MC 0x2 > @@ -1275,6 +1314,8 @@ int kvm_s390_handle_b9(struct kvm_vcpu *vcpu) > return handle_essa(vcpu); > case 0xaf: > return handle_pfmf(vcpu); > + case 0xd3: > + return handle_rpcit(vcpu); > default: > return -EOPNOTSUPP; > } >
-- Pierre Morel IBM Lab Boeblingen
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