On 13/03/12 19:50, Jan Kiszka wrote:
Please tag uq/master patches with "PATCH uq/master".
On 2012-03-13 11:42, Amos Kong wrote:
Older kernels have a 6 device limit on the KVM io bus.
This patch makes kvm_has_many_ioeventfds() return available
ioeventfd count. ioeventfd will be disabled if there is
no 7 available ioeventfds.
Signed-off-by: Amos Kong<akong@xxxxxxxxxx>
---
hw/virtio-pci.c | 2 +-
kvm-all.c | 9 +++------
2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index a0fb7c1..d63f303 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -678,7 +678,7 @@ void virtio_init_pci(VirtIOPCIProxy *proxy, VirtIODevice *vdev)
pci_register_bar(&proxy->pci_dev, 0, PCI_BASE_ADDRESS_SPACE_IO,
&proxy->bar);
- if (!kvm_has_many_ioeventfds()) {
+ if (kvm_has_many_ioeventfds() != 7) {
proxy->flags&= ~VIRTIO_PCI_FLAG_USE_IOEVENTFD;
}
diff --git a/kvm-all.c b/kvm-all.c
index 3c6b4f0..d12694b 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -78,7 +78,6 @@ struct KVMState
int pit_in_kernel;
int pit_state2;
int xsave, xcrs;
- int many_ioeventfds;
int irqchip_inject_ioctl;
#ifdef KVM_CAP_IRQ_ROUTING
struct kvm_irq_routing *irq_routes;
@@ -510,8 +509,8 @@ static int kvm_check_many_ioeventfds(void)
}
}
- /* Decide whether many devices are supported or not */
- ret = i == ARRAY_SIZE(ioeventfds);
+ /* If i equals to 7, many devices are supported */
+ ret = i;
while (i--> 0) {
kvm_set_ioeventfd_pio_word(ioeventfds[i], 0, i, false);
@@ -1078,8 +1077,6 @@ int kvm_init(void)
kvm_state = s;
memory_listener_register(&kvm_memory_listener, NULL);
- s->many_ioeventfds = kvm_check_many_ioeventfds();
-
cpu_interrupt_handler = kvm_handle_interrupt;
return 0;
@@ -1407,7 +1404,7 @@ int kvm_has_many_ioeventfds(void)
if (!kvm_enabled()) {
return 0;
}
- return kvm_state->many_ioeventfds;
+ return kvm_check_many_ioeventfds();
And why are you dropping the caching of the kvm_check_many_ioeventfds()
return value? Is kvm_has_many_ioeventfds not used outside init scopes?
Hi Jan,
In the past, kvm_state->many_ioeventfds is only updated once at the
beginning,
I want to use kvm_check_many_ioeventfds() to check if available
ioeventfd exists
before starting ioeventfd each time.
--
Amos.
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