Currently, MSI messages can only be injected to in-kernel irqchips by
defining a corresponding IRQ route for each message. This is not only
unhandy if the MSI messages are generated "on the fly" by user space,
IRQ routes are a limited resource that user space as to manage
carefully.
By providing a direct injection with, we can both avoid using up limited
resources and simplify the necessary steps for user land. The API
already provides a channel (flags) to revoke an injected but not yet
delivered message which will become important for in-kernel MSI-X vector
masking support.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 23 +++++++++++++++++++++++
include/linux/kvm.h | 15 +++++++++++++++
virt/kvm/kvm_main.c | 18 ++++++++++++++++++
3 files changed, 56 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 7945b0b..f4c3de3 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1383,6 +1383,29 @@ The following flags are defined:
If datamatch flag is set, the event will be signaled only if the written value
to the registered address is equal to datamatch in struct kvm_ioeventfd.
+4.59 KVM_SET_MSI
+
+Capability: KVM_CAP_SET_MSI
+Architectures: x86 ia64
+Type: vm ioctl
+Parameters: struct kvm_msi (in)
+Returns: 0 on success, -1 on error
+
+Directly inject a MSI message. Only valid with in-kernel irqchip that handles
+MSI messages.
+
+struct kvm_msi {
+ __u32 address_lo;
+ __u32 address_hi;
+ __u32 data;
+ __u32 flags;
+ __u8 pad[16];
+};
+
+The following flags are defined:
+
+#define KVM_MSI_FLAG_RAISE (1 << 0)
+
4.62 KVM_CREATE_SPAPR_TCE
Capability: KVM_CAP_SPAPR_TCE
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 6884054..83875ed 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -557,6 +557,9 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_PPC_HIOR 67
#define KVM_CAP_PPC_PAPR 68
#define KVM_CAP_S390_GMAP 71
+#ifdef __KVM_HAVE_MSI
+#define KVM_CAP_SET_MSI 72
+#endif
#ifdef KVM_CAP_IRQ_ROUTING
@@ -636,6 +639,16 @@ struct kvm_clock_data {
__u32 pad[9];
};
+#define KVM_MSI_FLAG_RAISE (1 << 0)
+
+struct kvm_msi {
+ __u32 address_lo;
+ __u32 address_hi;
+ __u32 data;
+ __u32 flags;
+ __u8 pad[16];
+};
+
/*
* ioctls for VM fds
*/
@@ -696,6 +709,8 @@ struct kvm_clock_data {
/* Available with KVM_CAP_TSC_CONTROL */
#define KVM_SET_TSC_KHZ _IO(KVMIO, 0xa2)
#define KVM_GET_TSC_KHZ _IO(KVMIO, 0xa3)
+/* Available with KVM_CAP_SET_MSI */
+#define KVM_SET_MSI _IOW(KVMIO, 0xa4, struct kvm_msi)
/*
* ioctls for vcpu fds
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d9cfb78..0e3a947 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2058,6 +2058,24 @@ static long kvm_vm_ioctl(struct file *filp,
mutex_unlock(&kvm->lock);
break;
#endif
+#ifdef __KVM_HAVE_MSI
+ case KVM_SET_MSI: {
+ struct kvm_kernel_irq_routing_entry route;
+ struct kvm_msi msi;
+
+ r = -EFAULT;
+ if (copy_from_user(&msi, argp, sizeof msi))
+ goto out;
+ route.msi.address_lo = msi.address_lo;
+ route.msi.address_hi = msi.address_hi;
+ route.msi.data = msi.data;
+ r = 0;
+ if (msi.flags & KVM_MSI_FLAG_RAISE)
+ r = kvm_set_msi(&route, kvm,
+ KVM_USERSPACE_IRQ_SOURCE_ID, 1);
+ break;
+ }
+#endif
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
if (r == -ENOTTY)
--
1.7.3.4
--
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