| Message ID | 20221110200603.141423-2-frank.heimes@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,F,1/1] KVM: s390: pv: don't present the ecall interrupt twice | expand |
On 10.11.22 21:06, frank.heimes@canonical.com wrote: > From: Nico Boehr <nrb@linux.ibm.com> > > BugLink: https://bugs.launchpad.net/bugs/1995941 > > When the SIGP interpretation facility is present and a VCPU sends an > ecall to another VCPU in enabled wait, the sending VCPU receives a 56 > intercept (partial execution), so KVM can wake up the receiving CPU. > Note that the SIGP interpretation facility will take care of the > interrupt delivery and KVM's only job is to wake the receiving VCPU. > > For PV, the sending VCPU will receive a 108 intercept (pv notify) and > should continue like in the non-PV case, i.e. wake the receiving VCPU. > > For PV and non-PV guests the interrupt delivery will occur through the > SIGP interpretation facility on SIE entry when SIE finds the X bit in > the status field set. > > However, in handle_pv_notification(), there was no special handling for > SIGP, which leads to interrupt injection being requested by KVM for the > next SIE entry. This results in the interrupt being delivered twice: > once by the SIGP interpretation facility and once by KVM through the > IICTL. > > Add the necessary special handling in handle_pv_notification(), similar > to handle_partial_execution(), which simply wakes the receiving VCPU and > leave interrupt delivery to the SIGP interpretation facility. > > In contrast to external calls, emergency calls are not interpreted but > also cause a 108 intercept, which is why we still need to call > handle_instruction() for SIGP orders other than ecall. > > Since kvm_s390_handle_sigp_pei() is now called for all SIGP orders which > cause a 108 intercept - even if they are actually handled by > handle_instruction() - move the tracepoint in kvm_s390_handle_sigp_pei() > to avoid possibly confusing trace messages. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Cc: <stable@vger.kernel.org> # 5.7 > Fixes: da24a0cc58ed ("KVM: s390: protvirt: Instruction emulation") > Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > Reviewed-by: Janosch Frank <frankja@linux.ibm.com> > Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> > Link: https://lore.kernel.org/r/20220718130434.73302-1-nrb@linux.ibm.com > Message-Id: <20220718130434.73302-1-nrb@linux.ibm.com> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > (cherry picked from commit c3f0e5fd2d33d80c5a5a8b5e5d2bab2841709cc8) > Signed-off-by: Frank Heimes <frank.heimes@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- > arch/s390/kvm/intercept.c | 15 +++++++++++++++ > arch/s390/kvm/sigp.c | 4 ++-- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c > index 5c10f96a50b1..9566b50d9da1 100644 > --- a/arch/s390/kvm/intercept.c > +++ b/arch/s390/kvm/intercept.c > @@ -527,12 +527,27 @@ static int handle_pv_uvc(struct kvm_vcpu *vcpu) > > static int handle_pv_notification(struct kvm_vcpu *vcpu) > { > + int ret; > + > if (vcpu->arch.sie_block->ipa == 0xb210) > return handle_pv_spx(vcpu); > if (vcpu->arch.sie_block->ipa == 0xb220) > return handle_pv_sclp(vcpu); > if (vcpu->arch.sie_block->ipa == 0xb9a4) > return handle_pv_uvc(vcpu); > + if (vcpu->arch.sie_block->ipa >> 8 == 0xae) { > + /* > + * Besides external call, other SIGP orders also cause a > + * 108 (pv notify) intercept. In contrast to external call, > + * these orders need to be emulated and hence the appropriate > + * place to handle them is in handle_instruction(). > + * So first try kvm_s390_handle_sigp_pei() and if that isn't > + * successful, go on with handle_instruction(). > + */ > + ret = kvm_s390_handle_sigp_pei(vcpu); > + if (!ret) > + return ret; > + } > > return handle_instruction(vcpu); > } > diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c > index 8aaee2892ec3..cb747bf6c798 100644 > --- a/arch/s390/kvm/sigp.c > +++ b/arch/s390/kvm/sigp.c > @@ -480,9 +480,9 @@ int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu) > struct kvm_vcpu *dest_vcpu; > u8 order_code = kvm_s390_get_base_disp_rs(vcpu, NULL); > > - trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); > - > if (order_code == SIGP_EXTERNAL_CALL) { > + trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); > + > dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr); > BUG_ON(dest_vcpu == NULL); >
On 10.11.22 21:06, frank.heimes@canonical.com wrote: > From: Nico Boehr <nrb@linux.ibm.com> > > BugLink: https://bugs.launchpad.net/bugs/1995941 > > When the SIGP interpretation facility is present and a VCPU sends an > ecall to another VCPU in enabled wait, the sending VCPU receives a 56 > intercept (partial execution), so KVM can wake up the receiving CPU. > Note that the SIGP interpretation facility will take care of the > interrupt delivery and KVM's only job is to wake the receiving VCPU. > > For PV, the sending VCPU will receive a 108 intercept (pv notify) and > should continue like in the non-PV case, i.e. wake the receiving VCPU. > > For PV and non-PV guests the interrupt delivery will occur through the > SIGP interpretation facility on SIE entry when SIE finds the X bit in > the status field set. > > However, in handle_pv_notification(), there was no special handling for > SIGP, which leads to interrupt injection being requested by KVM for the > next SIE entry. This results in the interrupt being delivered twice: > once by the SIGP interpretation facility and once by KVM through the > IICTL. > > Add the necessary special handling in handle_pv_notification(), similar > to handle_partial_execution(), which simply wakes the receiving VCPU and > leave interrupt delivery to the SIGP interpretation facility. > > In contrast to external calls, emergency calls are not interpreted but > also cause a 108 intercept, which is why we still need to call > handle_instruction() for SIGP orders other than ecall. > > Since kvm_s390_handle_sigp_pei() is now called for all SIGP orders which > cause a 108 intercept - even if they are actually handled by > handle_instruction() - move the tracepoint in kvm_s390_handle_sigp_pei() > to avoid possibly confusing trace messages. > > Signed-off-by: Nico Boehr <nrb@linux.ibm.com> > Cc: <stable@vger.kernel.org> # 5.7 > Fixes: da24a0cc58ed ("KVM: s390: protvirt: Instruction emulation") > Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > Reviewed-by: Janosch Frank <frankja@linux.ibm.com> > Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> > Link: https://lore.kernel.org/r/20220718130434.73302-1-nrb@linux.ibm.com > Message-Id: <20220718130434.73302-1-nrb@linux.ibm.com> > Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> > (cherry picked from commit c3f0e5fd2d33d80c5a5a8b5e5d2bab2841709cc8) > Signed-off-by: Frank Heimes <frank.heimes@canonical.com> Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> Thanks > --- > arch/s390/kvm/intercept.c | 15 +++++++++++++++ > arch/s390/kvm/sigp.c | 4 ++-- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c > index 5c10f96a50b1..9566b50d9da1 100644 > --- a/arch/s390/kvm/intercept.c > +++ b/arch/s390/kvm/intercept.c > @@ -527,12 +527,27 @@ static int handle_pv_uvc(struct kvm_vcpu *vcpu) > > static int handle_pv_notification(struct kvm_vcpu *vcpu) > { > + int ret; > + > if (vcpu->arch.sie_block->ipa == 0xb210) > return handle_pv_spx(vcpu); > if (vcpu->arch.sie_block->ipa == 0xb220) > return handle_pv_sclp(vcpu); > if (vcpu->arch.sie_block->ipa == 0xb9a4) > return handle_pv_uvc(vcpu); > + if (vcpu->arch.sie_block->ipa >> 8 == 0xae) { > + /* > + * Besides external call, other SIGP orders also cause a > + * 108 (pv notify) intercept. In contrast to external call, > + * these orders need to be emulated and hence the appropriate > + * place to handle them is in handle_instruction(). > + * So first try kvm_s390_handle_sigp_pei() and if that isn't > + * successful, go on with handle_instruction(). > + */ > + ret = kvm_s390_handle_sigp_pei(vcpu); > + if (!ret) > + return ret; > + } > > return handle_instruction(vcpu); > } > diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c > index 8aaee2892ec3..cb747bf6c798 100644 > --- a/arch/s390/kvm/sigp.c > +++ b/arch/s390/kvm/sigp.c > @@ -480,9 +480,9 @@ int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu) > struct kvm_vcpu *dest_vcpu; > u8 order_code = kvm_s390_get_base_disp_rs(vcpu, NULL); > > - trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); > - > if (order_code == SIGP_EXTERNAL_CALL) { > + trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); > + > dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr); > BUG_ON(dest_vcpu == NULL); >
diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index 5c10f96a50b1..9566b50d9da1 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -527,12 +527,27 @@ static int handle_pv_uvc(struct kvm_vcpu *vcpu) static int handle_pv_notification(struct kvm_vcpu *vcpu) { + int ret; + if (vcpu->arch.sie_block->ipa == 0xb210) return handle_pv_spx(vcpu); if (vcpu->arch.sie_block->ipa == 0xb220) return handle_pv_sclp(vcpu); if (vcpu->arch.sie_block->ipa == 0xb9a4) return handle_pv_uvc(vcpu); + if (vcpu->arch.sie_block->ipa >> 8 == 0xae) { + /* + * Besides external call, other SIGP orders also cause a + * 108 (pv notify) intercept. In contrast to external call, + * these orders need to be emulated and hence the appropriate + * place to handle them is in handle_instruction(). + * So first try kvm_s390_handle_sigp_pei() and if that isn't + * successful, go on with handle_instruction(). + */ + ret = kvm_s390_handle_sigp_pei(vcpu); + if (!ret) + return ret; + } return handle_instruction(vcpu); } diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index 8aaee2892ec3..cb747bf6c798 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -480,9 +480,9 @@ int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu) struct kvm_vcpu *dest_vcpu; u8 order_code = kvm_s390_get_base_disp_rs(vcpu, NULL); - trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); - if (order_code == SIGP_EXTERNAL_CALL) { + trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr); + dest_vcpu = kvm_get_vcpu_by_id(vcpu->kvm, cpu_addr); BUG_ON(dest_vcpu == NULL);