[PATCH 30/55] KVM: kvm_io_bus: Add kvm_io_bus_get_dev() call

Marc Zyngier
2016-07-22T17:28:47Z

From: Andre Przywara <andre.przywara@arm.com>

The kvm_io_bus framework is a nice place of holding information about
various MMIO regions for kernel emulated devices.
Add a call to retrieve the kvm_io_device structure which is associated
with a certain MMIO address. This avoids to duplicate kvm_io_bus'
knowledge of MMIO regions without having to fake MMIO calls if a user
needs the device a certain MMIO address belongs to.
This will be used by the ITS emulation to get the associated ITS device
when someone triggers an MSI via an ioctl from userspace.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
include/linux/kvm_host.h | 2 ++
virt/kvm/kvm_main.c | 24 ++++++++++++++++++++++++
2 files changed, 26 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0640ee9..614a981 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -164,6 +164,8 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, struct kvm_io_device *dev);
int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
struct kvm_io_device *dev);
+struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+ gpa_t addr);

#ifdef CONFIG_KVM_ASYNC_PF
struct kvm_async_pf {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ef54b4c..bd2eb92 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3496,6 +3496,30 @@ int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
return r;
}

+struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+ gpa_t addr)
+{
+ struct kvm_io_bus *bus;
+ int dev_idx, srcu_idx;
+ struct kvm_io_device *iodev = NULL;
+
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
+
+ dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1);
+ if (dev_idx < 0)
+ goto out_unlock;
+
+ iodev = bus->range[dev_idx].dev;
+
+out_unlock:
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+ return iodev;
+}
+EXPORT_SYMBOL_GPL(kvm_io_bus_get_dev);
+
static struct notifier_block kvm_cpu_notifier = {
.notifier_call = kvm_cpu_hotplug,
};
--
2.8.1