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Commit a991063c authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Greg Kroah-Hartman
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kvm: x86, powerpc: do not allow clearing largepages debugfs entry 



commit 833b45de69a6016c4b0cebe6765d526a31a81580 upstream.

The largepages debugfs entry is incremented/decremented as shadow
pages are created or destroyed.  Clearing it will result in an
underflow, which is harmless to KVM but ugly (and could be
misinterpreted by tools that use debugfs information), so make
this particular statistic read-only.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: kvm-ppc@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 580c79e7

arch/x86/kvm/x86.c

+3 −3
Original line number Diff line number Diff line
@@ -92,8 +92,8 @@ u64 __read_mostly efer_reserved_bits = ~((u64)(EFER_SCE | EFER_LME | EFER_LMA)); 
static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE);

#endif



#define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM

#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU

#define VM_STAT(x, ...) offsetof(struct kvm, stat.x), KVM_STAT_VM, ## __VA_ARGS__

#define VCPU_STAT(x, ...) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU, ## __VA_ARGS__



#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \

                                    KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)
@@ -205,7 +205,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { 
	{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },

	{ "mmu_unsync", VM_STAT(mmu_unsync) },

	{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },

	{ "largepages", VM_STAT(lpages) },

	{ "largepages", VM_STAT(lpages, .mode = 0444) },

	{ "max_mmu_page_hash_collisions",

		VM_STAT(max_mmu_page_hash_collisions) },

	{ NULL }

include/linux/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -1034,6 +1034,7 @@ enum kvm_stat_kind { 


struct kvm_stat_data {

	int offset;

	int mode;

	struct kvm *kvm;

};
@@ -1041,6 +1042,7 @@ struct kvm_stats_debugfs_item { 
	const char *name;

	int offset;

	enum kvm_stat_kind kind;

	int mode;

};

extern struct kvm_stats_debugfs_item debugfs_entries[];

extern struct dentry *kvm_debugfs_dir;

virt/kvm/kvm_main.c

+7 −3
Original line number Diff line number Diff line
@@ -616,8 +616,9 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd) 


		stat_data->kvm = kvm;

		stat_data->offset = p->offset;

		stat_data->mode = p->mode ? p->mode : 0644;

		kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;

		debugfs_create_file(p->name, 0644, kvm->debugfs_dentry,

		debugfs_create_file(p->name, stat_data->mode, kvm->debugfs_dentry,

				    stat_data, stat_fops_per_vm[p->kind]);

	}

	return 0;
@@ -3714,7 +3715,9 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, 
	if (!refcount_inc_not_zero(&stat_data->kvm->users_count))

		return -ENOENT;



	if (simple_attr_open(inode, file, get, set, fmt)) {

	if (simple_attr_open(inode, file, get,

			     stat_data->mode & S_IWUGO ? set : NULL,

			     fmt)) {

		kvm_put_kvm(stat_data->kvm);

		return -ENOMEM;

	}
@@ -3962,7 +3965,8 @@ static void kvm_init_debug(void) 


	kvm_debugfs_num_entries = 0;

	for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {

		debugfs_create_file(p->name, 0644, kvm_debugfs_dir,

		int mode = p->mode ? p->mode : 0644;

		debugfs_create_file(p->name, mode, kvm_debugfs_dir,

				    (void *)(long)p->offset,

				    stat_fops[p->kind]);

	}