From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Krowiak Subject: Re: [PATCH v10 01/26] KVM: s390: vsie: simulate VCPU SIE entry/exit Date: Mon, 24 Sep 2018 12:53:16 -0400 Message-ID: <32107210-1b83-dbef-89b7-96416483e0c4@linux.ibm.com> References: <1536781396-13601-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1536781396-13601-2-git-send-email-akrowiak@linux.vnet.ibm.com> <0ade216d-b206-abe3-418c-199d9278e37e@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <0ade216d-b206-abe3-418c-199d9278e37e@de.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Christian Borntraeger , Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, cohuck@redhat.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com, frankja@linux.ibm.com, David Hildenbrand List-ID: On 09/24/2018 06:32 AM, Christian Borntraeger wrote: > > > On 09/12/2018 09:42 PM, Tony Krowiak wrote: >> From: David Hildenbrand >> >> VCPU requests and VCPU blocking right now don't take care of the vSIE >> (as it was not necessary until now). But we want to have synchronous VCPU >> requests that will also be handled before running the vSIE again. >> >> So let's simulate a SIE entry of the VCPU when calling the sie during >> vSIE handling and check for PROG_ flags. The existing infrastructure >> (e.g. exit_sie()) will then detect that the SIE (in form of the vSIE) is >> running and properly kick the vSIE CPU, resulting in it leaving the vSIE >> loop and therefore the vSIE interception handler, allowing it to handle >> VCPU requests. >> >> E.g. if we want to modify the crycb of the VCPU and make sure that any >> masks also get applied to the VSIE crycb shadow (which uses masks from the >> VCPU crycb), we will need a way to hinder the vSIE from running and make >> sure to process the updated crycb before reentering the vSIE again. >> >> Reviewed-by: Pierre Morel >> Reviewed-by: Cornelia Huck >> Reviewed-by: Janosch Frank >> Signed-off-by: Tony Krowiak >> Signed-off-by: David Hildenbrand > > I guess you should want to swap both signoffs? In the end they should show the > patch flow. Will do. > > Other than that: > Reviewed-by: Christian Borntraeger > > >> --- >> arch/s390/kvm/kvm-s390.c | 9 ++++++++- >> arch/s390/kvm/kvm-s390.h | 1 + >> arch/s390/kvm/vsie.c | 21 +++++++++++++++++---- >> 3 files changed, 26 insertions(+), 5 deletions(-) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index f69333f..0b5aff0 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -2768,18 +2768,25 @@ static void kvm_s390_vcpu_request(struct kvm_vcpu *vcpu) >> exit_sie(vcpu); >> } >> >> +bool kvm_s390_vcpu_sie_inhibited(struct kvm_vcpu *vcpu) >> +{ >> + return atomic_read(&vcpu->arch.sie_block->prog20) & >> + (PROG_BLOCK_SIE | PROG_REQUEST); >> +} >> + >> static void kvm_s390_vcpu_request_handled(struct kvm_vcpu *vcpu) >> { >> atomic_andnot(PROG_REQUEST, &vcpu->arch.sie_block->prog20); >> } >> >> /* >> - * Kick a guest cpu out of SIE and wait until SIE is not running. >> + * Kick a guest cpu out of (v)SIE and wait until (v)SIE is not running. >> * If the CPU is not running (e.g. waiting as idle) the function will >> * return immediately. */ >> void exit_sie(struct kvm_vcpu *vcpu) >> { >> kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOP_INT); >> + kvm_s390_vsie_kick(vcpu); >> while (vcpu->arch.sie_block->prog0c & PROG_IN_SIE) >> cpu_relax(); >> } >> diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h >> index 981e3ba..1f6e36c 100644 >> --- a/arch/s390/kvm/kvm-s390.h >> +++ b/arch/s390/kvm/kvm-s390.h >> @@ -290,6 +290,7 @@ void kvm_s390_set_tod_clock(struct kvm *kvm, >> void kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu); >> void kvm_s390_vcpu_block(struct kvm_vcpu *vcpu); >> void kvm_s390_vcpu_unblock(struct kvm_vcpu *vcpu); >> +bool kvm_s390_vcpu_sie_inhibited(struct kvm_vcpu *vcpu); >> void exit_sie(struct kvm_vcpu *vcpu); >> void kvm_s390_sync_request(int req, struct kvm_vcpu *vcpu); >> int kvm_s390_vcpu_setup_cmma(struct kvm_vcpu *vcpu); >> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c >> index a2b28cd..12b9707 100644 >> --- a/arch/s390/kvm/vsie.c >> +++ b/arch/s390/kvm/vsie.c >> @@ -830,7 +830,7 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; >> struct kvm_s390_sie_block *scb_o = vsie_page->scb_o; >> int guest_bp_isolation; >> - int rc; >> + int rc = 0; >> >> handle_last_fault(vcpu, vsie_page); >> >> @@ -858,7 +858,18 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> guest_enter_irqoff(); >> local_irq_enable(); >> >> - rc = sie64a(scb_s, vcpu->run->s.regs.gprs); >> + /* >> + * Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking >> + * and VCPU requests also hinder the vSIE from running and lead >> + * to an immediate exit. kvm_s390_vsie_kick() has to be used to >> + * also kick the vSIE. >> + */ >> + vcpu->arch.sie_block->prog0c |= PROG_IN_SIE; >> + barrier(); >> + if (!kvm_s390_vcpu_sie_inhibited(vcpu)) >> + rc = sie64a(scb_s, vcpu->run->s.regs.gprs); >> + barrier(); >> + vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE; >> >> local_irq_disable(); >> guest_exit_irqoff(); >> @@ -1005,7 +1016,8 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> if (rc == -EAGAIN) >> rc = 0; >> if (rc || scb_s->icptcode || signal_pending(current) || >> - kvm_s390_vcpu_has_irq(vcpu, 0)) >> + kvm_s390_vcpu_has_irq(vcpu, 0) || >> + kvm_s390_vcpu_sie_inhibited(vcpu)) >> break; >> } >> >> @@ -1122,7 +1134,8 @@ int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu) >> if (unlikely(scb_addr & 0x1ffUL)) >> return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); >> >> - if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0)) >> + if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0) || >> + kvm_s390_vcpu_sie_inhibited(vcpu)) >> return 0; >> >> vsie_page = get_vsie_page(vcpu->kvm, scb_addr); >>