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@xxxxxxx>
>> ---
>> 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.
--
Jazz is not dead. It just smells funny...
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