| Message ID | 20120313104232.8741.89133.stgit@dhcp-8-167.nay.redhat.com |
|---|---|
| State | New |
| Headers | show |
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@redhat.com> > --- > 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? Jan
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@redhat.com> >> --- >> 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.
On 2012-03-13 13:00, Amos Kong wrote: > 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@redhat.com> >>> --- >>> 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, And the additional use case of patch 2 is not hot path either, right? > I want to use kvm_check_many_ioeventfds() to check if available > ioeventfd exists > before starting ioeventfd each time. OK, but than kvm_has_many_ioeventfds is not the right name for this function anymore. Call it "kvm_get_available_ioventfds" or so, but not in a away that implies a boolean return value. Jan
----- Original Message ----- > On 2012-03-13 13:00, Amos Kong wrote: > > 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@redhat.com> > >>> --- > >>> 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, > > And the additional use case of patch 2 is not hot path either, right? Hi Jan, It's not hot, it's called during init virtio-pci devices. > > I want to use kvm_check_many_ioeventfds() to check if available > > ioeventfd exists > > before starting ioeventfd each time. > > OK, but than kvm_has_many_ioeventfds is not the right name for this > function anymore. Call it "kvm_get_available_ioventfds" or so, but > not > in a away that implies a boolean return value. Yeah, will fix it in v2. Amos.
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(); } int kvm_has_gsi_routing(void)
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@redhat.com> --- hw/virtio-pci.c | 2 +- kvm-all.c | 9 +++------ 2 files changed, 4 insertions(+), 7 deletions(-)