[v2,2/2] KVM: ARM: add irqfd support

Message ID 1408969139-14700-3-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric Aug. 25, 2014, 12:18 p.m.
This patch enables irqfd on ARM.

irqfd framework enables to inject a virtual IRQ into a guest upon an
eventfd trigger. User-side uses KVM_IRQFD VM ioctl to provide KVM with
a kvm_irqfd struct that associates a VM, an eventfd, an IRQ number
(aka. the gsi). When an actor signals the eventfd (typically a VFIO
platform driver), the kvm irqfd subsystem injects the provided virtual
IRQ into the guest.

Resamplefd also is supported for level sensitive interrupts, ie. the
user can provide another eventfd that is triggered when the completion
of the virtual IRQ (gsi) is detected by the GIC.

The gsi must correspond to a shared peripheral interrupt (SPI), ie the
GIC interrupt ID is gsi+32.

this patch enables CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD.

No IRQ routing table is used.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---

This patch deprecates the previous patch featuring GSI routing
(https://patches.linaro.org/32261/)

irqchip.c and irq_comm.c are not used at all.

This RFC applies on top of Christoffer Dall's serie
arm/arm64: KVM: Various VGIC cleanups and improvements
https://lists.cs.columbia.edu/pipermail/kvmarm/2014-June/009979.html

All pieces can be found on git://git.linaro.org/people/eric.auger/linux.git
branch irqfd_integ_v5

This work was tested with Calxeda Midway xgmac main interrupt with
qemu-system-arm and QEMU VFIO platform device.

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              |  3 ++-
 arch/arm/kvm/Makefile             |  2 +-
 virt/kvm/arm/vgic.c               | 56 ++++++++++++++++++++++++++++++++++++---
 5 files changed, 62 insertions(+), 7 deletions(-)

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index beae3fd..8118b12 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2204,7 +2204,7 @@  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
@@ -2230,6 +2230,9 @@  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/arm64 the injected must be a shared peripheral interrupt (SPI).
+This means the 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 e6ebdd3..3034c66 100644
--- a/arch/arm/include/uapi/asm/kvm.h
+++ b/arch/arm/include/uapi/asm/kvm.h
@@ -194,6 +194,9 @@  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 466bd29..82ccd81 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.
@@ -55,7 +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_IRQCHIP
+	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/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 7164d2e..586bd11 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1334,7 +1334,10 @@  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;
+	int is_assigned_irq;
 
 	kvm_debug("STATUS = %08x\n", status);
 
@@ -1351,6 +1354,7 @@  static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 			struct vgic_lr vlr = vgic_get_lr(vcpu, lr);
 			BUG_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;
@@ -1363,6 +1367,18 @@  static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
 			 * interrupt.
 			 */
 			vgic_dist_irq_clear_soft_pend(vcpu, vlr.irq);
+			spin_unlock(&dist->lock);
+
+			is_assigned_irq = kvm_irq_has_notifier(kvm, 0,
+						vlr.irq - VGIC_NR_PRIVATE_IRQS);
+
+			if (is_assigned_irq) {
+				kvm_debug("EOI irqchip routed vIRQ %d\n",
+					  vlr.irq);
+				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)) {
@@ -1377,6 +1393,8 @@  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.
@@ -1441,14 +1459,10 @@  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)
@@ -2183,3 +2197,37 @@  struct kvm_device_ops kvm_arm_vgic_v2_ops = {
 	.get_attr = vgic_get_attr,
 	.has_attr = vgic_has_attr,
 };
+
+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)
+{
+	int r = -EINVAL;
+	unsigned int spi = irq + VGIC_NR_PRIVATE_IRQS;
+
+	if (spi > KVM_ARM_IRQ_GIC_MAX)
+		return r;
+
+	kvm_debug("Inject irqchip routed vIRQ %d\n", irq);
+	r = kvm_vgic_inject_irq(kvm, 0, spi, level);
+	return r;
+}
+
+/* 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;
+}