From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Add a new ioctl KVM_MAP_MEMORY in the KVM common code. It iterates on the
memory range and calls the arch-specific function. Add stub arch function
as a weak symbol.
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
v2:
- Drop need_resched(). (David, Sean, Kai)
- Move cond_resched() at the end of loop. (Kai)
- Drop added check. (David)
- Use EINTR instead of ERESTART. (David, Sean)
- Fix srcu lock leak. (Kai, Sean)
- Add comment above copy_to_user().
- Drop pointless comment. (Sean)
- Drop kvm_arch_vcpu_pre_map_memory(). (Sean)
- Don't overwrite error code. (Sean, David)
- Make the parameter in bytes, not pages. (Michael)
- Drop source member in struct kvm_memory_mapping. (Sean, Michael)
---
include/linux/kvm_host.h | 3 +++
include/uapi/linux/kvm.h | 9 +++++++
virt/kvm/kvm_main.c | 54 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 48f31dcd318a..e56a0c7e5b42 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2445,4 +2445,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
}
#endif /* CONFIG_KVM_PRIVATE_MEM */
+int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping);
+
#endif
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 2190adbe3002..972aa9e054d3 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -917,6 +917,7 @@ struct kvm_enable_cap {
#define KVM_CAP_MEMORY_ATTRIBUTES 233
#define KVM_CAP_GUEST_MEMFD 234
#define KVM_CAP_VM_TYPES 235
+#define KVM_CAP_MAP_MEMORY 236
struct kvm_irq_routing_irqchip {
__u32 irqchip;
@@ -1548,4 +1549,12 @@ struct kvm_create_guest_memfd {
__u64 reserved[6];
};
+#define KVM_MAP_MEMORY _IOWR(KVMIO, 0xd5, struct kvm_memory_mapping)
+
+struct kvm_memory_mapping {
+ __u64 base_address;
+ __u64 size;
+ __u64 flags;
+};
+
#endif /* __LINUX_KVM_H */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fb49c2a60200..f2ad9e106cdb 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4415,6 +4415,48 @@ static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
return fd;
}
+__weak int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping)
+{
+ return -EOPNOTSUPP;
+}
+
+static int kvm_vcpu_map_memory(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping)
+{
+ int idx, r;
+
+ if (mapping->flags)
+ return -EINVAL;
+
+ if (!PAGE_ALIGNED(mapping->base_address) ||
+ !PAGE_ALIGNED(mapping->size) ||
+ mapping->base_address + mapping->size <= mapping->base_address)
+ return -EINVAL;
+
+ vcpu_load(vcpu);
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+ r = 0;
+ while (mapping->size) {
+ if (signal_pending(current)) {
+ r = -EINTR;
+ break;
+ }
+
+ r = kvm_arch_vcpu_map_memory(vcpu, mapping);
+ if (r)
+ break;
+
+ cond_resched();
+ }
+
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ vcpu_put(vcpu);
+
+ return r;
+}
+
static long kvm_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -4616,6 +4658,18 @@ static long kvm_vcpu_ioctl(struct file *filp,
r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
break;
}
+ case KVM_MAP_MEMORY: {
+ struct kvm_memory_mapping mapping;
+
+ r = -EFAULT;
+ if (copy_from_user(&mapping, argp, sizeof(mapping)))
+ break;
+ r = kvm_vcpu_map_memory(vcpu, &mapping);
+ /* Don't check error to tell the processed range. */
+ if (copy_to_user(argp, &mapping, sizeof(mapping)))
+ r = -EFAULT;
+ break;
+ }
default:
r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
}
--
2.43.2
