KVM: Remove subtle "struct kvm_stats_desc" pseudo-overlay

Remove KVM's internal pseudo-overlay of kvm_stats_desc, which subtly
aliases the flexible name[] in the uAPI definition with a fixed-size array
of the same name.  The unusual embedded structure results in compiler
warnings due to -Wflex-array-member-not-at-end, and also necessitates an
extra level of dereferencing in KVM.  To avoid the "overlay", define the
uAPI structure to have a fixed-size name when building for the kernel.

Opportunistically clean up the indentation for the stats macros, and
replace spaces with tabs.

No functional change intended.

Reported-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Closes: https://lore.kernel.org/all/aPfNKRpLfhmhYqfP@kspp
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
[..]
Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://patch.msgid.link/20251205232655.445294-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

2 files changed, 11 insertions, 11 deletions

diff --git a/virt/kvm/binary_stats.c b/virt/kvm/binary_stats.c
index eefca6c69f51..76ce697c773b 100644
--- a/virt/kvm/binary_stats.c
+++ b/virt/kvm/binary_stats.c
@@ -50,7 +50,7 @@
  * Return: the number of bytes that has been successfully read
  */
 ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header,
-		       const struct _kvm_stats_desc *desc,
+		       const struct kvm_stats_desc *desc,
 		       void *stats, size_t size_stats,
 		       char __user *user_buffer, size_t size, loff_t *offset)
 {
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5b5b69c97665..cf65fd82d36d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -983,9 +983,9 @@ static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
 		kvm_free_memslot(kvm, memslot);
 }
 
-static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
+static umode_t kvm_stats_debugfs_mode(const struct kvm_stats_desc *desc)
 {
-	switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
+	switch (desc->flags & KVM_STATS_TYPE_MASK) {
 	case KVM_STATS_TYPE_INSTANT:
 		return 0444;
 	case KVM_STATS_TYPE_CUMULATIVE:
@@ -1020,7 +1020,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
 	struct dentry *dent;
 	char dir_name[ITOA_MAX_LEN * 2];
 	struct kvm_stat_data *stat_data;
-	const struct _kvm_stats_desc *pdesc;
+	const struct kvm_stats_desc *pdesc;
 	int i, ret = -ENOMEM;
 	int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
 				      kvm_vcpu_stats_header.num_desc;
@@ -6186,11 +6186,11 @@ static int kvm_stat_data_get(void *data, u64 *val)
 	switch (stat_data->kind) {
 	case KVM_STAT_VM:
 		r = kvm_get_stat_per_vm(stat_data->kvm,
-					stat_data->desc->desc.offset, val);
+					stat_data->desc->offset, val);
 		break;
 	case KVM_STAT_VCPU:
 		r = kvm_get_stat_per_vcpu(stat_data->kvm,
-					  stat_data->desc->desc.offset, val);
+					  stat_data->desc->offset, val);
 		break;
 	}
 
@@ -6208,11 +6208,11 @@ static int kvm_stat_data_clear(void *data, u64 val)
 	switch (stat_data->kind) {
 	case KVM_STAT_VM:
 		r = kvm_clear_stat_per_vm(stat_data->kvm,
-					  stat_data->desc->desc.offset);
+					  stat_data->desc->offset);
 		break;
 	case KVM_STAT_VCPU:
 		r = kvm_clear_stat_per_vcpu(stat_data->kvm,
-					    stat_data->desc->desc.offset);
+					    stat_data->desc->offset);
 		break;
 	}
 
@@ -6360,7 +6360,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
 static void kvm_init_debug(void)
 {
 	const struct file_operations *fops;
-	const struct _kvm_stats_desc *pdesc;
+	const struct kvm_stats_desc *pdesc;
 	int i;
 
 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
@@ -6373,7 +6373,7 @@ static void kvm_init_debug(void)
 			fops = &vm_stat_readonly_fops;
 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
 				kvm_debugfs_dir,
-				(void *)(long)pdesc->desc.offset, fops);
+				(void *)(long)pdesc->offset, fops);
 	}
 
 	for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
@@ -6384,7 +6384,7 @@ static void kvm_init_debug(void)
 			fops = &vcpu_stat_readonly_fops;
 		debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
 				kvm_debugfs_dir,
-				(void *)(long)pdesc->desc.offset, fops);
+				(void *)(long)pdesc->offset, fops);
 	}
 }