[PATCH] KVM: Add reading critical region for kvm_io_bus_read/write

Sheng Yang
2010-12-06T08:42:29Z

Seems we missed it.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
Do we need this, or slot_lock covered this?

virt/kvm/kvm_main.c | 24 ++++++++++++++++--------
1 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c4ee364..3e71b91 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2228,28 +2228,36 @@ static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val)
{
- int i;
+ int i, idx, r = -EOPNOTSUPP;
struct kvm_io_bus *bus;

+ idx = srcu_read_lock(&kvm->srcu);
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
for (i = 0; i < bus->dev_count; i++)
- if (!kvm_iodevice_write(bus->devs[i], addr, len, val))
- return 0;
- return -EOPNOTSUPP;
+ if (!kvm_iodevice_write(bus->devs[i], addr, len, val)) {
+ r = 0;
+ break;
+ }
+ srcu_read_unlock(&kvm->srcu, idx);
+ return r;
}

/* kvm_io_bus_read - called under kvm->slots_lock */
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val)
{
- int i;
+ int i, idx, r = -EOPNOTSUPP;
struct kvm_io_bus *bus;

+ idx = srcu_read_lock(&kvm->srcu);
bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
for (i = 0; i < bus->dev_count; i++)
- if (!kvm_iodevice_read(bus->devs[i], addr, len, val))
- return 0;
- return -EOPNOTSUPP;
+ if (!kvm_iodevice_read(bus->devs[i], addr, len, val)) {
+ r = 0;
+ break;
+ }
+ srcu_read_unlock(&kvm->srcu, idx);
+ return r;
}

/* Caller must hold slots_lock. */
--
1.7.0.1