[PATCH v4 2/3] KVM: arm: add irqfd support
Eric Auger
eric.auger at linaro.org
Sun Nov 23 09:56:59 PST 2014
This patch enables irqfd on arm.
Both irqfd and resamplefd are supported. Injection is implemented
in vgic.c without routing.
This patch enables CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD.
KVM_CAP_IRQFD is now advertised. KVM_CAP_IRQFD_RESAMPLE capability
automatically is advertised as soon as CONFIG_HAVE_KVM_IRQFD is set.
Signed-off-by: Eric Auger <eric.auger at linaro.org>
---
v3 -> v4:
- reword commit message
- explain why we unlock the distributor before calling kvm_notify_acked_irq
- rename is_assigned_irq into has_notifier
- change EOI and injection kvm_debug format string
- remove error local variable in kvm_set_irq
- Move HAVE_KVM_IRQCHIP unset in a separate patch
- The rationale behind not supporting PPI irqfd injection is that
any device using a PPI would be a private-to-the-CPU device (timer for
instance), so its state would have to be context-switched along with the
VCPU and would require in-kernel wiring anyhow. It is not a relevant use
case for irqfds.
- handle case were the irqfd injection is attempted before the vgic is ready.
in such a case the notifier, if any, is called immediatly
- use nr_irqs to test spi is within correct range
v2 -> v3:
- removal of irq.h from eventfd.c put in a separate patch to increase
visibility
- properly expose KVM_CAP_IRQFD capability in arm.c
- remove CONFIG_HAVE_KVM_IRQCHIP meaningfull only if irq_comm.c is used
v1 -> v2:
- rebase on 3.17rc1
- move of the dist unlock in process_maintenance
- remove of dist lock in __kvm_vgic_sync_hwstate
- rewording of the commit message (add resamplefd reference)
- remove irq.h
---
Documentation/virtual/kvm/api.txt | 5 ++-
arch/arm/include/uapi/asm/kvm.h | 3 ++
arch/arm/kvm/Kconfig | 2 ++
arch/arm/kvm/Makefile | 2 +-
arch/arm/kvm/arm.c | 3 ++
virt/kvm/arm/vgic.c | 72 ++++++++++++++++++++++++++++++++++++---
6 files changed, 81 insertions(+), 6 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 7610eaa..4deccc0 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2206,7 +2206,7 @@ into the hash PTE second double word).
4.75 KVM_IRQFD
Capability: KVM_CAP_IRQFD
-Architectures: x86 s390
+Architectures: x86 s390 arm
Type: vm ioctl
Parameters: struct kvm_irqfd (in)
Returns: 0 on success, -1 on error
@@ -2232,6 +2232,9 @@ Note that closing the resamplefd is not sufficient to disable the
irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment
and need not be specified with KVM_IRQFD_FLAG_DEASSIGN.
+On arm, the gsi must be a shared peripheral interrupt (SPI).
+This means the corresponding programmed GIC interrupt ID is gsi+32.
+
4.76 KVM_PPC_ALLOCATE_HTAB
Capability: KVM_CAP_PPC_ALLOC_HTAB
diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
index 09ee408..77547bb 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -196,6 +196,9 @@ struct kvm_arch_memory_slot {
/* Highest supported SPI, from VGIC_NR_IRQS */
#define KVM_ARM_IRQ_GIC_MAX 127
+/* One single KVM irqchip, ie. the VGIC */
+#define KVM_NR_IRQCHIPS 1
+
/* PSCI interface */
#define KVM_PSCI_FN_BASE 0x95c1ba5e
#define KVM_PSCI_FN(n) (KVM_PSCI_FN_BASE + (n))
diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index 9f581b1..e519a40 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -24,6 +24,7 @@ config KVM
select KVM_MMIO
select KVM_ARM_HOST
depends on ARM_VIRT_EXT && ARM_LPAE
+ select HAVE_KVM_EVENTFD
---help---
Support hosting virtualized guest machines. You will also
need to select one or more of the processor modules below.
@@ -55,6 +56,7 @@ config KVM_ARM_MAX_VCPUS
config KVM_ARM_VGIC
bool "KVM support for Virtual GIC"
depends on KVM_ARM_HOST && OF
+ select HAVE_KVM_IRQFD
default y
---help---
Adds support for a hardware assisted, in-kernel GIC emulation.
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index f7057ed..859db09 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -15,7 +15,7 @@ AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
KVM := ../../../virt/kvm
-kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
+kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o
obj-y += kvm-arm.o init.o interrupts.o
obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9e193c8..fb75af2 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -172,6 +172,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_IRQCHIP:
r = vgic_present;
break;
+#ifdef CONFIG_HAVE_KVM_IRQFD
+ case KVM_CAP_IRQFD:
+#endif
case KVM_CAP_DEVICE_CTRL:
case KVM_CAP_USER_MEMORY:
case KVM_CAP_SYNC_MMU:
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 3aaca49..3417776 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1446,7 +1446,10 @@ epilog:
static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
{
u32 status = vgic_get_interrupt_status(vcpu);
+ struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
bool level_pending = false;
+ struct kvm *kvm = vcpu->kvm;
+ bool has_notifier;
kvm_debug("STATUS = %08x\n", status);
@@ -1463,6 +1466,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
struct vgic_lr vlr = vgic_get_lr(vcpu, lr);
WARN_ON(vgic_irq_is_edge(vcpu, vlr.irq));
+ spin_lock(&dist->lock);
vgic_irq_clear_queued(vcpu, vlr.irq);
WARN_ON(vlr.state & LR_STATE_MASK);
vlr.state = 0;
@@ -1481,6 +1485,24 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
*/
vgic_dist_irq_clear_soft_pend(vcpu, vlr.irq);
+ /*
+ * Unlock the distributor since kvm_notify_acked_irq
+ * will call kvm_set_irq to reset the IRQ level.
+ * This latter attempts to grab dist->lock
+ */
+ spin_unlock(&dist->lock);
+
+ has_notifier = kvm_irq_has_notifier(kvm, 0,
+ vlr.irq - VGIC_NR_PRIVATE_IRQS);
+
+ if (has_notifier) {
+ kvm_debug("Guest EOIed vIRQ %d on CPU %d\n",
+ vlr.irq, vcpu->vcpu_id);
+ kvm_notify_acked_irq(kvm, 0,
+ vlr.irq - VGIC_NR_PRIVATE_IRQS);
+ }
+ spin_lock(&dist->lock);
+
/* Any additional pending interrupt? */
if (vgic_dist_irq_get_level(vcpu, vlr.irq)) {
vgic_cpu_irq_set(vcpu, vlr.irq);
@@ -1490,6 +1512,8 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
vgic_cpu_irq_clear(vcpu, vlr.irq);
}
+ spin_unlock(&dist->lock);
+
/*
* Despite being EOIed, the LR may not have
* been marked as empty.
@@ -1554,14 +1578,10 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
{
- struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
-
if (!irqchip_in_kernel(vcpu->kvm))
return;
- spin_lock(&dist->lock);
__kvm_vgic_sync_hwstate(vcpu);
- spin_unlock(&dist->lock);
}
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
@@ -2477,3 +2497,47 @@ out_free_irq:
free_percpu_irq(vgic->maint_irq, kvm_get_running_vcpus());
return ret;
}
+
+int kvm_irq_map_gsi(struct kvm *kvm,
+ struct kvm_kernel_irq_routing_entry *entries,
+ int gsi)
+{
+ return gsi;
+}
+
+int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
+{
+ return pin;
+}
+
+int kvm_set_irq(struct kvm *kvm, int irq_source_id,
+ u32 irq, int level, bool line_status)
+{
+ unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;
+
+ kvm_debug("irqfd sets vIRQ %d to %d\n", irq, level);
+
+ if (likely(vgic_initialized(kvm))) {
+ if (spi > kvm->arch.vgic.nr_irqs)
+ return -EINVAL;
+ return kvm_vgic_inject_irq(kvm, 0, spi, level);
+ } else if (level && kvm_irq_has_notifier(kvm, 0, irq)) {
+ /*
+ * any IRQ injected before vgic readiness is
+ * ignored and the notifier, if any, is called
+ * immediately as if the virtual IRQ were completed
+ * by the guest
+ */
+ kvm_notify_acked_irq(kvm, 0, irq);
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+/* MSI not implemented yet */
+int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+ struct kvm *kvm, int irq_source_id,
+ int level, bool line_status)
+{
+ return 0;
+}
--
1.9.1
More information about the linux-arm-kernel
mailing list