[RFC PATCH] ARM: KVM: add irqfd support
From: Eric Auger
Date: Mon Aug 04 2014 - 08:09:36 EST
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.
The gsi must correspond to a shared peripheral interrupt (SPI), ie the
GIC interrupt ID is gsi+32.
CONFIG_HAVE_KVM_EVENTFD and CONFIG_HAVE_KVM_IRQFD are turned on.
No IRQ routing table is used thanks to Paul Mackerras' patch serie:
"IRQFD without IRQ routing, enabled for XICS"
(https://www.mail-archive.com/kvm@xxxxxxxxxxxxxxx/msg104478.html)
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
This patch would deprecate 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_v4
This work was tested with Calxeda Midway xgmac main interrupt with
qemu-system-arm and QEMU VFIO platform device.
---
Documentation/virtual/kvm/api.txt | 5 +++-
arch/arm/include/uapi/asm/kvm.h | 3 +++
arch/arm/kvm/Kconfig | 3 ++-
arch/arm/kvm/Makefile | 2 +-
arch/arm/kvm/irq.h | 25 ++++++++++++++++++
virt/kvm/arm/vgic.c | 54 ++++++++++++++++++++++++++++++++++++---
6 files changed, 85 insertions(+), 7 deletions(-)
create mode 100644 arch/arm/kvm/irq.h
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 0fe3649..04310d9 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2132,7 +2132,7 @@ 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
@@ -2158,6 +2158,9 @@ 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 4be5bb1..7800261 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 && !CPU_BIG_ENDIAN
+ 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 789bca9..2fa2f82 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/irq.h b/arch/arm/kvm/irq.h
new file mode 100644
index 0000000..1275d91
--- /dev/null
+++ b/arch/arm/kvm/irq.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ * Authors: Eric Auger <eric.auger@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __IRQ_H
+#define __IRQ_H
+
+#include <linux/kvm_host.h>
+/*
+ * Placeholder for irqchip and irq/msi routing declarations
+ * included in irqchip.c
+ */
+
+#endif
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 123030b..907e735 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1259,7 +1259,10 @@ epilog:
static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+ struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
bool level_pending = false;
+ struct kvm *kvm = vcpu->kvm;
+ int is_assigned_irq;
kvm_debug("MISR = %08x\n", vgic_cpu->vgic_misr);
@@ -1273,6 +1276,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
for_each_set_bit(lr, (unsigned long *)vgic_cpu->vgic_eisr,
vgic_cpu->nr_lr) {
irq = vgic_cpu->vgic_lr[lr] & GICH_LR_VIRTUALID;
+ spin_lock(&dist->lock);
BUG_ON(vgic_irq_is_edge(vcpu, irq));
vgic_irq_clear_queued(vcpu, irq);
@@ -1285,6 +1289,17 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
* interrupt.
*/
vgic_dist_irq_clear_soft_pend(vcpu, irq);
+ spin_unlock(&dist->lock);
+
+ is_assigned_irq = kvm_irq_has_notifier(kvm, 0,
+ irq - VGIC_NR_PRIVATE_IRQS);
+
+ if (is_assigned_irq) {
+ kvm_debug("EOI irqchip routed vIRQ %d\n", irq);
+ kvm_notify_acked_irq(kvm, 0,
+ irq - VGIC_NR_PRIVATE_IRQS);
+ }
+ spin_lock(&dist->lock);
/* Any additional pending interrupt? */
if (vgic_dist_irq_get_level(vcpu, irq)) {
@@ -1305,6 +1320,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
*/
set_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr);
vgic_cpu->vgic_lr[lr] &= ~GICH_LR_ACTIVE_BIT;
+ spin_unlock(&dist->lock);
}
}
@@ -1344,8 +1360,10 @@ static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
/* Check if we still have something up our sleeve... */
pending = find_first_zero_bit((unsigned long *)vgic_cpu->vgic_elrsr,
vgic_cpu->nr_lr);
+ spin_lock(&dist->lock);
if (level_pending || pending < vgic_cpu->nr_lr)
set_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
+ spin_unlock(&dist->lock);
}
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
@@ -1362,14 +1380,10 @@ 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)
@@ -2146,3 +2160,35 @@ 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;
+}
--
1.9.1
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