| Message ID | 20190611170336.121706-9-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm/arm64: vgic: ITS translation cache | expand |
Hi Marc, On 6/11/19 7:03 PM, Marc Zyngier wrote: > When performing an MSI injection, let's first check if the translation > is already in the cache. If so, let's inject it quickly without > going through the whole translation process. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++++ > virt/kvm/arm/vgic/vgic.h | 1 + > 2 files changed, 37 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index 62932458476a..83d80ec33473 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -577,6 +577,20 @@ static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist, > return irq; > } > > +static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db, > + u32 devid, u32 eventid) > +{ > + struct vgic_dist *dist = &kvm->arch.vgic; > + struct vgic_irq *irq; > + unsigned long flags; > + > + raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); > + irq = __vgic_its_check_cache(dist, db, devid, eventid); > + raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); > + > + return irq; > +} > + > static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, > u32 devid, u32 eventid, > struct vgic_irq *irq) > @@ -736,6 +750,25 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, > return 0; > } > > +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi) > +{ > + struct vgic_irq *irq; > + unsigned long flags; > + phys_addr_t db; > + > + db = (u64)msi->address_hi << 32 | msi->address_lo; > + irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data); I think we miss a check of its->enabled. This is currently done in vgic_its_resolve_lpi() but now likely to be bypassed. Doing that in this function is needed for next patch I think. Thanks Eric > + > + if (!irq) > + return -1; > + > + raw_spin_lock_irqsave(&irq->irq_lock, flags); > + irq->pending_latch = true; > + vgic_queue_irq_unlock(kvm, irq, flags); > + > + return 0; > +} > + > /* > * Queries the KVM IO bus framework to get the ITS pointer from the given > * doorbell address. > @@ -747,6 +780,9 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) > struct vgic_its *its; > int ret; > > + if (!vgic_its_inject_cached_translation(kvm, msi)) > + return 1; > + > its = vgic_msi_to_its(kvm, msi); > if (IS_ERR(its)) > return PTR_ERR(its); > diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h > index 072f810dc441..ad6eba1e2beb 100644 > --- a/virt/kvm/arm/vgic/vgic.h > +++ b/virt/kvm/arm/vgic/vgic.h > @@ -317,6 +317,7 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr); > int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its, > u32 devid, u32 eventid, struct vgic_irq **irq); > struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi); > +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi); > void vgic_lpi_translation_cache_init(struct kvm *kvm); > void vgic_lpi_translation_cache_destroy(struct kvm *kvm); > void vgic_its_invalidate_cache(struct kvm *kvm); >
Hi Eric, On 23/07/2019 16:10, Auger Eric wrote: > Hi Marc, > > On 6/11/19 7:03 PM, Marc Zyngier wrote: >> When performing an MSI injection, let's first check if the translation >> is already in the cache. If so, let's inject it quickly without >> going through the whole translation process. >> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++++ >> virt/kvm/arm/vgic/vgic.h | 1 + >> 2 files changed, 37 insertions(+) >> >> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c >> index 62932458476a..83d80ec33473 100644 >> --- a/virt/kvm/arm/vgic/vgic-its.c >> +++ b/virt/kvm/arm/vgic/vgic-its.c >> @@ -577,6 +577,20 @@ static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist, >> return irq; >> } >> >> +static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db, >> + u32 devid, u32 eventid) >> +{ >> + struct vgic_dist *dist = &kvm->arch.vgic; >> + struct vgic_irq *irq; >> + unsigned long flags; >> + >> + raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); >> + irq = __vgic_its_check_cache(dist, db, devid, eventid); >> + raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); >> + >> + return irq; >> +} >> + >> static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, >> u32 devid, u32 eventid, >> struct vgic_irq *irq) >> @@ -736,6 +750,25 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, >> return 0; >> } >> >> +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi) >> +{ >> + struct vgic_irq *irq; >> + unsigned long flags; >> + phys_addr_t db; >> + >> + db = (u64)msi->address_hi << 32 | msi->address_lo; >> + irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data); > > I think we miss a check of its->enabled. This is currently done in > vgic_its_resolve_lpi() but now likely to be bypassed. But why would a translation be cached if the ITS is disabled? It should never haver been there the first place (vgic_its_resolve_lpi does check for the ITS being enabled, as you pointed out). Which makes me think that we miss an invalidate on an ITS being disabled: diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 2633b0e88981..5f2ad74ad834 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -1719,6 +1719,8 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its, goto out; its->enabled = !!(val & GITS_CTLR_ENABLE); + if (!its->enabled) + vgic_its_invalidate_cache(kvm); /* * Try to process any pending commands. This function bails out early What do you think? M.
Hi Marc, On 7/23/19 5:45 PM, Marc Zyngier wrote: > Hi Eric, > > On 23/07/2019 16:10, Auger Eric wrote: >> Hi Marc, >> >> On 6/11/19 7:03 PM, Marc Zyngier wrote: >>> When performing an MSI injection, let's first check if the translation >>> is already in the cache. If so, let's inject it quickly without >>> going through the whole translation process. >>> >>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >>> --- >>> virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++++ >>> virt/kvm/arm/vgic/vgic.h | 1 + >>> 2 files changed, 37 insertions(+) >>> >>> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c >>> index 62932458476a..83d80ec33473 100644 >>> --- a/virt/kvm/arm/vgic/vgic-its.c >>> +++ b/virt/kvm/arm/vgic/vgic-its.c >>> @@ -577,6 +577,20 @@ static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist, >>> return irq; >>> } >>> >>> +static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db, >>> + u32 devid, u32 eventid) >>> +{ >>> + struct vgic_dist *dist = &kvm->arch.vgic; >>> + struct vgic_irq *irq; >>> + unsigned long flags; >>> + >>> + raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); >>> + irq = __vgic_its_check_cache(dist, db, devid, eventid); >>> + raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); >>> + >>> + return irq; >>> +} >>> + >>> static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, >>> u32 devid, u32 eventid, >>> struct vgic_irq *irq) >>> @@ -736,6 +750,25 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, >>> return 0; >>> } >>> >>> +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi) >>> +{ >>> + struct vgic_irq *irq; >>> + unsigned long flags; >>> + phys_addr_t db; >>> + >>> + db = (u64)msi->address_hi << 32 | msi->address_lo; >>> + irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data); >> >> I think we miss a check of its->enabled. This is currently done in >> vgic_its_resolve_lpi() but now likely to be bypassed. > > But why would a translation be cached if the ITS is disabled? It should > never haver been there the first place (vgic_its_resolve_lpi does check > for the ITS being enabled, as you pointed out). > > Which makes me think that we miss an invalidate on an ITS being disabled: > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index 2633b0e88981..5f2ad74ad834 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -1719,6 +1719,8 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its, > goto out; > > its->enabled = !!(val & GITS_CTLR_ENABLE); > + if (!its->enabled) > + vgic_its_invalidate_cache(kvm); > > /* > * Try to process any pending commands. This function bails out early > > > What do you think? Yes I agree this is the right way to fix it. Thanks Eric > > M. >
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 62932458476a..83d80ec33473 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -577,6 +577,20 @@ static struct vgic_irq *__vgic_its_check_cache(struct vgic_dist *dist, return irq; } +static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db, + u32 devid, u32 eventid) +{ + struct vgic_dist *dist = &kvm->arch.vgic; + struct vgic_irq *irq; + unsigned long flags; + + raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); + irq = __vgic_its_check_cache(dist, db, devid, eventid); + raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); + + return irq; +} + static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, u32 devid, u32 eventid, struct vgic_irq *irq) @@ -736,6 +750,25 @@ static int vgic_its_trigger_msi(struct kvm *kvm, struct vgic_its *its, return 0; } +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi) +{ + struct vgic_irq *irq; + unsigned long flags; + phys_addr_t db; + + db = (u64)msi->address_hi << 32 | msi->address_lo; + irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data); + + if (!irq) + return -1; + + raw_spin_lock_irqsave(&irq->irq_lock, flags); + irq->pending_latch = true; + vgic_queue_irq_unlock(kvm, irq, flags); + + return 0; +} + /* * Queries the KVM IO bus framework to get the ITS pointer from the given * doorbell address. @@ -747,6 +780,9 @@ int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi) struct vgic_its *its; int ret; + if (!vgic_its_inject_cached_translation(kvm, msi)) + return 1; + its = vgic_msi_to_its(kvm, msi); if (IS_ERR(its)) return PTR_ERR(its); diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h index 072f810dc441..ad6eba1e2beb 100644 --- a/virt/kvm/arm/vgic/vgic.h +++ b/virt/kvm/arm/vgic/vgic.h @@ -317,6 +317,7 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr); int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its, u32 devid, u32 eventid, struct vgic_irq **irq); struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi); +int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi); void vgic_lpi_translation_cache_init(struct kvm *kvm); void vgic_lpi_translation_cache_destroy(struct kvm *kvm); void vgic_its_invalidate_cache(struct kvm *kvm);
When performing an MSI injection, let's first check if the translation is already in the cache. If so, let's inject it quickly without going through the whole translation process. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++++ virt/kvm/arm/vgic/vgic.h | 1 + 2 files changed, 37 insertions(+)