From: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
Currently the numbers of MSI vectors come from register PCI_MSI_FLAGS
which should be power-of-2, but in some scenaries it is not the same as
the number that driver requires in guest, for example, a PCI driver wants
to allocate 6 MSI vecotrs in guest, but as the limitation, it will allocate
8 MSI vectors. So it requires 8 MSI vectors in qemu while the driver in
guest only wants to allocate 6 MSI vectors.
When GICv4.1 is enabled, we can see some exception print as following for
above scenaro:
vfio-pci 0000:3a:00.1: irq bypass producer (token 000000008f08224d) registration fails:66311
In order to verify whether a MSI vector is valid, add KVM_VERIFY_MSI to do
that. If there is a mapping, return 0, otherwise return negative value.
This is the kernel part of adding system call KVM_VERIFY_MSI.
Signed-off-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
---
arch/arm64/kvm/vgic/vgic-irqfd.c | 5 +++++
arch/arm64/kvm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++++
arch/arm64/kvm/vgic/vgic.h | 1 +
include/linux/kvm_host.h | 2 +-
include/uapi/linux/kvm.h | 2 ++
virt/kvm/kvm_main.c | 9 +++++++++
6 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/vgic/vgic-irqfd.c b/arch/arm64/kvm/vgic/vgic-irqfd.c
index 475059b..2312da6 100644
--- a/arch/arm64/kvm/vgic/vgic-irqfd.c
+++ b/arch/arm64/kvm/vgic/vgic-irqfd.c
@@ -98,6 +98,11 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
return vgic_its_inject_msi(kvm, &msi);
}
+int kvm_verify_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+ return vgic_its_verify_msi(kvm, msi);
+}
+
/**
* kvm_arch_set_irq_inatomic: fast-path for irqfd injection
*/
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 24d7778..cae6183 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -767,6 +767,42 @@ int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi)
return 0;
}
+int vgic_its_verify_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+ struct vgic_its *its;
+ struct its_ite *ite;
+ struct kvm_vcpu *vcpu;
+ int ret = 0;
+
+ if (!irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
+ return -EINVAL;
+
+ if (!vgic_has_its(kvm))
+ return -ENODEV;
+
+ its = vgic_msi_to_its(kvm, msi);
+ if (IS_ERR(its))
+ return PTR_ERR(its);
+
+ mutex_lock(&its->its_lock);
+ if (!its->enabled) {
+ ret = -EBUSY;
+ goto unlock;
+ }
+ ite = find_ite(its, msi->devid, msi->data);
+ if (!ite || !its_is_collection_mapped(ite->collection)) {
+ ret = -E_ITS_INT_UNMAPPED_INTERRUPT;
+ goto unlock;
+ }
+
+ vcpu = kvm_get_vcpu(kvm, ite->collection->target_addr);
+ if (!vcpu)
+ ret = -E_ITS_INT_UNMAPPED_INTERRUPT;
+unlock:
+ mutex_unlock(&its->its_lock);
+ return ret;
+}
+
/*
* Queries the KVM IO bus framework to get the ITS pointer from the given
* doorbell address.
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index 0c8da72..d452150 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -240,6 +240,7 @@ int kvm_vgic_register_its_device(void);
void vgic_enable_lpis(struct kvm_vcpu *vcpu);
void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu);
int vgic_its_inject_msi(struct kvm *kvm, struct kvm_msi *msi);
+int vgic_its_verify_msi(struct kvm *kvm, struct kvm_msi *msi);
int vgic_v3_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr);
int vgic_v3_dist_uaccess(struct kvm_vcpu *vcpu, bool is_write,
int offset, u32 *val);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 32f259f..7923352 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1597,7 +1597,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
int kvm_request_irq_source_id(struct kvm *kvm);
void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
-
+int kvm_verify_msi(struct kvm *kvm, struct kvm_msi *msi);
/*
* Returns a pointer to the memslot if it contains gfn.
* Otherwise returns NULL.
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0d5d441..72b28f8 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1543,6 +1543,8 @@ struct kvm_s390_ucas_mapping {
#define KVM_PPC_SVM_OFF _IO(KVMIO, 0xb3)
#define KVM_ARM_MTE_COPY_TAGS _IOR(KVMIO, 0xb4, struct kvm_arm_copy_mte_tags)
+#define KVM_VERIFY_MSI _IOW(KVMIO, 0xb5, struct kvm_msi)
+
/* ioctl for vm fd */
#define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct kvm_create_device)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e30f1b4..439bdd7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4728,6 +4728,15 @@ static long kvm_vm_ioctl(struct file *filp,
r = kvm_send_userspace_msi(kvm, &msi);
break;
}
+ case KVM_VERIFY_MSI: {
+ struct kvm_msi msi;
+
+ r = -EFAULT;
+ if (copy_from_user(&msi, argp, sizeof(msi)))
+ goto out;
+ r = kvm_verify_msi(kvm, &msi);
+ break;
+ }
#endif
#ifdef __KVM_HAVE_IRQ_LINE
case KVM_IRQ_LINE_STATUS:
--
2.8.1
