From: James Hogan <james.hogan@imgtec.com> To: <linux-mips@linux-mips.org> Cc: "James Hogan" <james.hogan@imgtec.com>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, "Ralf Baechle" <ralf@linux-mips.org>, kvm@vger.kernel.org Subject: [PATCH 3/10] KVM: MIPS: Update vcpu->mode and vcpu->cpu Date: Mon, 9 Jan 2017 20:51:55 +0000 [thread overview] Message-ID: <5ba3054eea35eeca00b2a653f40ebbed3e6940f3.1483993967.git-series.james.hogan@imgtec.com> (raw) In-Reply-To: <cover.4133d2f24fd73c1889a46ea05bb8924867b33747.1483993967.git-series.james.hogan@imgtec.com> Keep the vcpu->mode and vcpu->cpu variables up to date so that kvm_make_all_cpus_request() has a chance of functioning correctly. This will soon need to be used for kvm_flush_remote_tlbs(). We can easily update vcpu->cpu when the VCPU context is loaded or saved, which will happen when accessing guest context and when the guest is scheduled in and out. We need to be a little careful with vcpu->mode though, as we will in future be checking for outstanding VCPU requests, and this must be done after the value of IN_GUEST_MODE in vcpu->mode is visible to other CPUs. Otherwise the other CPU could fail to trigger an IPI to wait for completion dispite the VCPU request not being seen. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/mips.c | 18 ++++++++++++++++++ arch/mips/kvm/mmu.c | 2 ++ 2 files changed, 20 insertions(+), 0 deletions(-) diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 90c28fbf4829..325e98367b30 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -365,6 +365,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) guest_enter_irqoff(); trace_kvm_enter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_run() callback is not + * reordered ahead of the write to vcpu->mode, or we could miss a TLB + * flush request while the requester sees the VCPU as outside of guest + * mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + r = kvm_mips_callbacks->vcpu_run(run, vcpu); trace_kvm_out(vcpu); @@ -1331,6 +1339,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) u32 inst; int ret = RESUME_GUEST; + vcpu->mode = OUTSIDE_GUEST_MODE; + /* re-enable HTW before enabling interrupts */ htw_start(); @@ -1486,6 +1496,14 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) if (ret == RESUME_GUEST) { trace_kvm_reenter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_reenter() + * callback is not reordered ahead of the write to vcpu->mode, + * or we could miss a TLB flush request while the requester sees + * the VCPU as outside of guest mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + kvm_mips_callbacks->vcpu_reenter(run, vcpu); /* diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c index 09f5da706d9a..e41ee36dd626 100644 --- a/arch/mips/kvm/mmu.c +++ b/arch/mips/kvm/mmu.c @@ -696,6 +696,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) local_irq_save(flags); + vcpu->cpu = cpu; if (vcpu->arch.last_sched_cpu != cpu) { kvm_debug("[%d->%d]KVM VCPU[%d] switch\n", vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); @@ -723,6 +724,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) cpu = smp_processor_id(); vcpu->arch.last_sched_cpu = cpu; + vcpu->cpu = -1; /* save guest state in registers */ kvm_mips_callbacks->vcpu_put(vcpu, cpu); -- git-series 0.8.10
WARNING: multiple messages have this Message-ID (diff)
From: James Hogan <james.hogan@imgtec.com> To: linux-mips@linux-mips.org Cc: "James Hogan" <james.hogan@imgtec.com>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, "Ralf Baechle" <ralf@linux-mips.org>, kvm@vger.kernel.org Subject: [PATCH 3/10] KVM: MIPS: Update vcpu->mode and vcpu->cpu Date: Mon, 9 Jan 2017 20:51:55 +0000 [thread overview] Message-ID: <5ba3054eea35eeca00b2a653f40ebbed3e6940f3.1483993967.git-series.james.hogan@imgtec.com> (raw) Message-ID: <20170109205155.kZClo1Wcja4-xa2VJFe79EJE2NRgdozj4t9i9S3izxA@z> (raw) In-Reply-To: <cover.4133d2f24fd73c1889a46ea05bb8924867b33747.1483993967.git-series.james.hogan@imgtec.com> Keep the vcpu->mode and vcpu->cpu variables up to date so that kvm_make_all_cpus_request() has a chance of functioning correctly. This will soon need to be used for kvm_flush_remote_tlbs(). We can easily update vcpu->cpu when the VCPU context is loaded or saved, which will happen when accessing guest context and when the guest is scheduled in and out. We need to be a little careful with vcpu->mode though, as we will in future be checking for outstanding VCPU requests, and this must be done after the value of IN_GUEST_MODE in vcpu->mode is visible to other CPUs. Otherwise the other CPU could fail to trigger an IPI to wait for completion dispite the VCPU request not being seen. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/kvm/mips.c | 18 ++++++++++++++++++ arch/mips/kvm/mmu.c | 2 ++ 2 files changed, 20 insertions(+), 0 deletions(-) diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 90c28fbf4829..325e98367b30 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -365,6 +365,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) guest_enter_irqoff(); trace_kvm_enter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_run() callback is not + * reordered ahead of the write to vcpu->mode, or we could miss a TLB + * flush request while the requester sees the VCPU as outside of guest + * mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + r = kvm_mips_callbacks->vcpu_run(run, vcpu); trace_kvm_out(vcpu); @@ -1331,6 +1339,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) u32 inst; int ret = RESUME_GUEST; + vcpu->mode = OUTSIDE_GUEST_MODE; + /* re-enable HTW before enabling interrupts */ htw_start(); @@ -1486,6 +1496,14 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) if (ret == RESUME_GUEST) { trace_kvm_reenter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_reenter() + * callback is not reordered ahead of the write to vcpu->mode, + * or we could miss a TLB flush request while the requester sees + * the VCPU as outside of guest mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + kvm_mips_callbacks->vcpu_reenter(run, vcpu); /* diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c index 09f5da706d9a..e41ee36dd626 100644 --- a/arch/mips/kvm/mmu.c +++ b/arch/mips/kvm/mmu.c @@ -696,6 +696,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) local_irq_save(flags); + vcpu->cpu = cpu; if (vcpu->arch.last_sched_cpu != cpu) { kvm_debug("[%d->%d]KVM VCPU[%d] switch\n", vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id); @@ -723,6 +724,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) cpu = smp_processor_id(); vcpu->arch.last_sched_cpu = cpu; + vcpu->cpu = -1; /* save guest state in registers */ kvm_mips_callbacks->vcpu_put(vcpu, cpu); -- git-series 0.8.10
next prev parent reply other threads:[~2017-01-09 20:54 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-01-09 20:51 [PATCH 0/10] KVM: MIPS: Implement GPA page tables and shadow flushing James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:51 ` [PATCH 1/10] MIPS: Add return errors to protected cache ops James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-17 16:05 ` Ralf Baechle 2017-01-09 20:51 ` [PATCH 2/10] KVM: MIPS/MMU: Convert guest physical map to page table James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:51 ` James Hogan [this message] 2017-01-09 20:51 ` [PATCH 3/10] KVM: MIPS: Update vcpu->mode and vcpu->cpu James Hogan 2017-01-09 20:51 ` [PATCH 4/10] KVM: MIPS/T&E: Handle TLB invalidation requests James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:51 ` [PATCH 5/10] KVM: MIPS/T&E: Reduce stale ASID checks James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:51 ` [PATCH 6/10] KVM: MIPS/T&E: Add lockless GVA access helpers James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:51 ` [PATCH 7/10] KVM: MIPS/T&E: Use lockless GVA helpers for dyntrans James Hogan 2017-01-09 20:51 ` James Hogan 2017-01-09 20:52 ` [PATCH 8/10] KVM: MIPS/MMU: Use lockless GVA helpers for get_inst() James Hogan 2017-01-09 20:52 ` James Hogan 2017-01-09 20:52 ` [PATCH 9/10] KVM: MIPS/Emulate: Use lockless GVA helpers for cache emulation James Hogan 2017-01-09 20:52 ` James Hogan 2017-01-09 20:52 ` [PATCH 10/10] KVM: MIPS: Implement kvm_arch_flush_shadow_all/memslot James Hogan 2017-01-09 20:52 ` James Hogan
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