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Message-ID: <20250401161106.790710-10-pbonzini@redhat.com>
Date: Tue, 1 Apr 2025 18:10:46 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
kvm@...r.kernel.org
Cc: roy.hopkins@...e.com,
seanjc@...gle.com,
thomas.lendacky@....com,
ashish.kalra@....com,
michael.roth@....com,
jroedel@...e.de,
nsaenz@...zon.com,
anelkz@...zon.de,
James.Bottomley@...senPartnership.com
Subject: [PATCH 09/29] KVM: implement plane file descriptors ioctl and creation
Add the file_operations for planes, the means to create new file
descriptors for them, and the KVM_CHECK_EXTENSION implementation for
the two new capabilities.
KVM_SIGNAL_MSI and KVM_SET_MEMORY_ATTRIBUTES are now available
through both vm and plane file descriptors, forward them to the
same function that is used by the file_operations for planes.
KVM_CHECK_EXTENSION instead remains separate, because it only
advertises a very small subset of capabilities when applied to
plane file descriptors.
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
include/linux/kvm_host.h | 19 +++++
include/uapi/linux/kvm.h | 2 +
virt/kvm/kvm_main.c | 154 +++++++++++++++++++++++++++++++++------
3 files changed, 154 insertions(+), 21 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0a91b556767e..dbca418d64f5 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -342,6 +342,8 @@ struct kvm_vcpu {
unsigned long guest_debug;
struct mutex mutex;
+
+ /* Shared for all planes */
struct kvm_run *run;
#ifndef __KVM_HAVE_ARCH_WQP
@@ -922,6 +924,23 @@ static inline void kvm_vm_bugged(struct kvm *kvm)
}
+#if KVM_MAX_VCPU_PLANES == 1
+static inline int kvm_arch_nr_vcpu_planes(struct kvm *kvm)
+{
+ return KVM_MAX_VCPU_PLANES;
+}
+
+static inline struct kvm_plane *vcpu_to_plane(struct kvm_vcpu *vcpu)
+{
+ return vcpu->kvm->planes[0];
+}
+#else
+static inline struct kvm_plane *vcpu_to_plane(struct kvm_vcpu *vcpu)
+{
+ return vcpu->kvm->planes[vcpu->plane_id];
+}
+#endif
+
#define KVM_BUG(cond, kvm, fmt...) \
({ \
bool __ret = !!(cond); \
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index b0cca93ebcb3..96d25c7fa18f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1690,4 +1690,6 @@ struct kvm_pre_fault_memory {
__u64 padding[5];
};
+#define KVM_CREATE_PLANE _IO(KVMIO, 0xd6)
+
#endif /* __LINUX_KVM_H */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index cd4dfc399cad..b08fea91dc74 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4388,6 +4388,80 @@ static int kvm_wait_for_vcpu_online(struct kvm_vcpu *vcpu)
return 0;
}
+static int kvm_plane_ioctl_check_extension(struct kvm_plane *plane, long arg)
+{
+ switch (arg) {
+#ifdef CONFIG_HAVE_KVM_MSI
+ case KVM_CAP_SIGNAL_MSI:
+#endif
+ case KVM_CAP_CHECK_EXTENSION_VM:
+ return 1;
+#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+ case KVM_CAP_MEMORY_ATTRIBUTES:
+ return kvm_supported_mem_attributes(plane);
+#endif
+ default:
+ return 0;
+ }
+}
+
+static long __kvm_plane_ioctl(struct kvm_plane *plane, unsigned int ioctl,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+
+ switch (ioctl) {
+#ifdef CONFIG_HAVE_KVM_MSI
+ case KVM_SIGNAL_MSI: {
+ struct kvm_msi msi;
+
+ if (copy_from_user(&msi, argp, sizeof(msi)))
+ return -EFAULT;
+ return kvm_send_userspace_msi(plane, &msi);
+ }
+#endif
+#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+ case KVM_SET_MEMORY_ATTRIBUTES: {
+ struct kvm_memory_attributes attrs;
+
+ if (copy_from_user(&attrs, argp, sizeof(attrs)))
+ return -EFAULT;
+ return kvm_vm_ioctl_set_mem_attributes(plane, &attrs);
+ }
+#endif
+ case KVM_CHECK_EXTENSION:
+ return kvm_plane_ioctl_check_extension(plane, arg);
+ default:
+ return -ENOTTY;
+ }
+}
+
+static long kvm_plane_ioctl(struct file *filp, unsigned int ioctl,
+ unsigned long arg)
+{
+ struct kvm_plane *plane = filp->private_data;
+
+ if (plane->kvm->mm != current->mm || plane->kvm->vm_dead)
+ return -EIO;
+
+ return __kvm_plane_ioctl(plane, ioctl, arg);
+}
+
+static int kvm_plane_release(struct inode *inode, struct file *filp)
+{
+ struct kvm_plane *plane = filp->private_data;
+
+ kvm_put_kvm(plane->kvm);
+ return 0;
+}
+
+static struct file_operations kvm_plane_fops = {
+ .unlocked_ioctl = kvm_plane_ioctl,
+ .release = kvm_plane_release,
+ KVM_COMPAT(kvm_plane_ioctl),
+};
+
+
static long kvm_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -4878,6 +4952,14 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
if (kvm)
return kvm_arch_nr_memslot_as_ids(kvm);
return KVM_MAX_NR_ADDRESS_SPACES;
+#endif
+#if KVM_MAX_VCPU_PLANES > 1
+ case KVM_CAP_PLANES:
+ if (kvm)
+ return kvm_arch_nr_vcpu_planes(kvm);
+ return KVM_MAX_PLANES;
+ case KVM_CAP_PLANES_FPU:
+ return kvm_arch_planes_share_fpu(kvm);
#endif
case KVM_CAP_NR_MEMSLOTS:
return KVM_USER_MEM_SLOTS;
@@ -5112,6 +5194,48 @@ static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm)
return fd;
}
+static int kvm_vm_ioctl_create_plane(struct kvm *kvm, unsigned id)
+{
+ struct kvm_plane *plane;
+ struct file *file;
+ int r, fd;
+
+ if (id >= KVM_MAX_VCPU_PLANES)
+ return -EINVAL;
+
+ guard(mutex)(&kvm->lock);
+ if (kvm->planes[id])
+ return -EEXIST;
+
+ fd = get_unused_fd_flags(O_CLOEXEC);
+ if (fd < 0)
+ return fd;
+
+ plane = kvm_create_vm_plane(kvm, id);
+ if (IS_ERR(plane)) {
+ r = PTR_ERR(plane);
+ goto put_fd;
+ }
+
+ kvm_get_kvm(kvm);
+ file = anon_inode_getfile("kvm-plane", &kvm_plane_fops, plane, O_RDWR);
+ if (IS_ERR(file)) {
+ r = PTR_ERR(file);
+ goto put_kvm;
+ }
+
+ kvm->planes[id] = plane;
+ fd_install(fd, file);
+ return fd;
+
+put_kvm:
+ kvm_put_kvm(kvm);
+ kfree(plane);
+put_fd:
+ put_unused_fd(fd);
+ return r;
+}
+
#define SANITY_CHECK_MEM_REGION_FIELD(field) \
do { \
BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) != \
@@ -5130,6 +5254,9 @@ static long kvm_vm_ioctl(struct file *filp,
if (kvm->mm != current->mm || kvm->vm_dead)
return -EIO;
switch (ioctl) {
+ case KVM_CREATE_PLANE:
+ r = kvm_vm_ioctl_create_plane(kvm, arg);
+ break;
case KVM_CREATE_VCPU:
r = kvm_vm_ioctl_create_vcpu(kvm, arg);
break;
@@ -5236,16 +5363,12 @@ static long kvm_vm_ioctl(struct file *filp,
break;
}
#ifdef CONFIG_HAVE_KVM_MSI
- case KVM_SIGNAL_MSI: {
- struct kvm_msi msi;
-
- r = -EFAULT;
- if (copy_from_user(&msi, argp, sizeof(msi)))
- goto out;
- r = kvm_send_userspace_msi(kvm->planes[0], &msi);
- break;
- }
+ case KVM_SIGNAL_MSI:
#endif
+#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+ case KVM_SET_MEMORY_ATTRIBUTES:
+#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
+ return __kvm_plane_ioctl(kvm->planes[0], ioctl, arg);
#ifdef __KVM_HAVE_IRQ_LINE
case KVM_IRQ_LINE_STATUS:
case KVM_IRQ_LINE: {
@@ -5301,18 +5424,6 @@ static long kvm_vm_ioctl(struct file *filp,
break;
}
#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
-#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
- case KVM_SET_MEMORY_ATTRIBUTES: {
- struct kvm_memory_attributes attrs;
-
- r = -EFAULT;
- if (copy_from_user(&attrs, argp, sizeof(attrs)))
- goto out;
-
- r = kvm_vm_ioctl_set_mem_attributes(kvm->planes[0], &attrs);
- break;
- }
-#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
case KVM_CREATE_DEVICE: {
struct kvm_create_device cd;
@@ -6467,6 +6578,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
+ kvm_plane_fops.owner = module;
kvm_device_fops.owner = module;
kvm_preempt_ops.sched_in = kvm_sched_in;
--
2.49.0
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