KVM: ARM: Inject IRQs and FIQs from userspace

All interrupt injection is now based on the VM ioctl KVM_IRQ_LINE.  This
works semantically well for the GIC as we in fact raise/lower a line on
a machine component (the gic).  The IOCTL uses the follwing struct.

struct kvm_irq_level {
	union {
		__u32 irq;     /* GSI */
		__s32 status;  /* not used for KVM_IRQ_LEVEL */
	};
	__u32 level;           /* 0 or 1 */
};

ARM can signal an interrupt either at the CPU level, or at the in-kernel irqchip
(GIC), and for in-kernel irqchip can tell the GIC to use PPIs designated for
specific cpus.  The irq field is interpreted like this:

  bits:  | 31 ... 24 | 23  ... 16 | 15    ...    0 |
  field: | irq_type  | vcpu_index |   irq_number   |

The irq_type field has the following values:
- irq_type[0]: out-of-kernel GIC: irq_number 0 is IRQ, irq_number 1 is FIQ
- irq_type[1]: in-kernel GIC: SPI, irq_number between 32 and 1019 (incl.)
               (the vcpu_index field is ignored)
- irq_type[2]: in-kernel GIC: PPI, irq_number between 16 and 31 (incl.)

The irq_number thus corresponds to the irq ID in as in the GICv2 specs.

This is documented in Documentation/kvm/api.txt.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
This commit is contained in:
Christoffer Dall 2013-01-20 18:28:08 -05:00 committed by Christoffer Dall
parent d5d8184d35
commit 86ce85352f
6 changed files with 134 additions and 4 deletions

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@ -615,15 +615,32 @@ created.
4.25 KVM_IRQ_LINE
Capability: KVM_CAP_IRQCHIP
Architectures: x86, ia64
Architectures: x86, ia64, arm
Type: vm ioctl
Parameters: struct kvm_irq_level
Returns: 0 on success, -1 on error
Sets the level of a GSI input to the interrupt controller model in the kernel.
Requires that an interrupt controller model has been previously created with
KVM_CREATE_IRQCHIP. Note that edge-triggered interrupts require the level
to be set to 1 and then back to 0.
On some architectures it is required that an interrupt controller model has
been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered
interrupts require the level to be set to 1 and then back to 0.
ARM can signal an interrupt either at the CPU level, or at the in-kernel irqchip
(GIC), and for in-kernel irqchip can tell the GIC to use PPIs designated for
specific cpus. The irq field is interpreted like this:
 bits: | 31 ... 24 | 23 ... 16 | 15 ... 0 |
field: | irq_type | vcpu_index | irq_id |
The irq_type field has the following values:
- irq_type[0]: out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ
- irq_type[1]: in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.)
(the vcpu_index field is ignored)
- irq_type[2]: in-kernel GIC: PPI, irq_id between 16 and 31 (incl.)
(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs)
In both cases, level is used to raise/lower the line.
struct kvm_irq_level {
union {

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@ -68,6 +68,7 @@
#define HCR_GUEST_MASK (HCR_TSC | HCR_TSW | HCR_TWI | HCR_VM | HCR_BSU_IS | \
HCR_FB | HCR_TAC | HCR_AMO | HCR_IMO | HCR_FMO | \
HCR_SWIO | HCR_TIDCP)
#define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
/* Hyp System Control Register (HSCTLR) bits */
#define HSCTLR_TE (1 << 30)

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@ -23,6 +23,7 @@
#include <asm/ptrace.h>
#define __KVM_HAVE_GUEST_DEBUG
#define __KVM_HAVE_IRQ_LINE
#define KVM_REG_SIZE(id) \
(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
@ -103,4 +104,24 @@ struct kvm_arch_memory_slot {
#define KVM_REG_ARM_CORE (0x0010 << KVM_REG_ARM_COPROC_SHIFT)
#define KVM_REG_ARM_CORE_REG(name) (offsetof(struct kvm_regs, name) / 4)
/* KVM_IRQ_LINE irq field index values */
#define KVM_ARM_IRQ_TYPE_SHIFT 24
#define KVM_ARM_IRQ_TYPE_MASK 0xff
#define KVM_ARM_IRQ_VCPU_SHIFT 16
#define KVM_ARM_IRQ_VCPU_MASK 0xff
#define KVM_ARM_IRQ_NUM_SHIFT 0
#define KVM_ARM_IRQ_NUM_MASK 0xffff
/* irq_type field */
#define KVM_ARM_IRQ_TYPE_CPU 0
#define KVM_ARM_IRQ_TYPE_SPI 1
#define KVM_ARM_IRQ_TYPE_PPI 2
/* out-of-kernel GIC cpu interrupt injection irq_number field */
#define KVM_ARM_IRQ_CPU_IRQ 0
#define KVM_ARM_IRQ_CPU_FIQ 1
/* Highest supported SPI, from VGIC_NR_IRQS */
#define KVM_ARM_IRQ_GIC_MAX 127
#endif /* __ARM_KVM_H__ */

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@ -24,6 +24,7 @@
#include <linux/fs.h>
#include <linux/mman.h>
#include <linux/sched.h>
#include <linux/kvm.h>
#include <trace/events/kvm.h>
#define CREATE_TRACE_POINTS
@ -284,6 +285,7 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
vcpu->cpu = cpu;
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
@ -319,6 +321,69 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
return -EINVAL;
}
static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level)
{
int bit_index;
bool set;
unsigned long *ptr;
if (number == KVM_ARM_IRQ_CPU_IRQ)
bit_index = __ffs(HCR_VI);
else /* KVM_ARM_IRQ_CPU_FIQ */
bit_index = __ffs(HCR_VF);
ptr = (unsigned long *)&vcpu->arch.irq_lines;
if (level)
set = test_and_set_bit(bit_index, ptr);
else
set = test_and_clear_bit(bit_index, ptr);
/*
* If we didn't change anything, no need to wake up or kick other CPUs
*/
if (set == level)
return 0;
/*
* The vcpu irq_lines field was updated, wake up sleeping VCPUs and
* trigger a world-switch round on the running physical CPU to set the
* virtual IRQ/FIQ fields in the HCR appropriately.
*/
kvm_vcpu_kick(vcpu);
return 0;
}
int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)
{
u32 irq = irq_level->irq;
unsigned int irq_type, vcpu_idx, irq_num;
int nrcpus = atomic_read(&kvm->online_vcpus);
struct kvm_vcpu *vcpu = NULL;
bool level = irq_level->level;
irq_type = (irq >> KVM_ARM_IRQ_TYPE_SHIFT) & KVM_ARM_IRQ_TYPE_MASK;
vcpu_idx = (irq >> KVM_ARM_IRQ_VCPU_SHIFT) & KVM_ARM_IRQ_VCPU_MASK;
irq_num = (irq >> KVM_ARM_IRQ_NUM_SHIFT) & KVM_ARM_IRQ_NUM_MASK;
trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);
if (irq_type != KVM_ARM_IRQ_TYPE_CPU)
return -EINVAL;
if (vcpu_idx >= nrcpus)
return -EINVAL;
vcpu = kvm_get_vcpu(kvm, vcpu_idx);
if (!vcpu)
return -EINVAL;
if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
return -EINVAL;
return vcpu_interrupt_line(vcpu, irq_num, level);
}
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{

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@ -39,6 +39,31 @@ TRACE_EVENT(kvm_exit,
TP_printk("PC: 0x%08lx", __entry->vcpu_pc)
);
TRACE_EVENT(kvm_irq_line,
TP_PROTO(unsigned int type, int vcpu_idx, int irq_num, int level),
TP_ARGS(type, vcpu_idx, irq_num, level),
TP_STRUCT__entry(
__field( unsigned int, type )
__field( int, vcpu_idx )
__field( int, irq_num )
__field( int, level )
),
TP_fast_assign(
__entry->type = type;
__entry->vcpu_idx = vcpu_idx;
__entry->irq_num = irq_num;
__entry->level = level;
),
TP_printk("Inject %s interrupt (%d), vcpu->idx: %d, num: %d, level: %d",
(__entry->type == KVM_ARM_IRQ_TYPE_CPU) ? "CPU" :
(__entry->type == KVM_ARM_IRQ_TYPE_PPI) ? "VGIC PPI" :
(__entry->type == KVM_ARM_IRQ_TYPE_SPI) ? "VGIC SPI" : "UNKNOWN",
__entry->type, __entry->vcpu_idx, __entry->irq_num, __entry->level)
);
TRACE_EVENT(kvm_unmap_hva,
TP_PROTO(unsigned long hva),
TP_ARGS(hva),

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@ -115,6 +115,7 @@ struct kvm_irq_level {
* ACPI gsi notion of irq.
* For IA-64 (APIC model) IOAPIC0: irq 0-23; IOAPIC1: irq 24-47..
* For X86 (standard AT mode) PIC0/1: irq 0-15. IOAPIC0: 0-23..
* For ARM: See Documentation/virtual/kvm/api.txt
*/
union {
__u32 irq;