[PATCH v3 13/22] KVM: Add arch hook when VM is added/deleted

isaku.yamahata
2022-09-02T02:19:34Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

and pass kvm_usage_count with kvm_lock. Move kvm_arch_post_init_vm() under
kvm_arch_add_vm(). Later kvm_arch_post_init_vm() is deleted once x86
overrides kvm_arch_add_vm().

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
include/linux/kvm_host.h | 2 ++
virt/kvm/kvm_arch.c | 12 +++++++++++-
virt/kvm/kvm_main.c | 21 +++++++++++++++++----
3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index dd2a6d98d4de..f78364e01ca9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1445,6 +1445,8 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);
bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu);
bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu);
int kvm_arch_post_init_vm(struct kvm *kvm);
+int kvm_arch_add_vm(struct kvm *kvm, int usage_count);
+int kvm_arch_del_vm(int usage_count);
void kvm_arch_pre_destroy_vm(struct kvm *kvm);
int kvm_arch_create_vm_debugfs(struct kvm *kvm);

diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
index 4748a76bcb03..0eac996f4981 100644
--- a/virt/kvm/kvm_arch.c
+++ b/virt/kvm/kvm_arch.c
@@ -10,11 +10,21 @@

#include <linux/kvm_host.h>

+__weak int kvm_arch_post_init_vm(struct kvm *kvm)
+{
+ return 0;
+}
+
/*
* Called after the VM is otherwise initialized, but just before adding it to
* the vm_list.
*/
-__weak int kvm_arch_post_init_vm(struct kvm *kvm)
+__weak int kvm_arch_add_vm(struct kvm *kvm, int usage_count)
+{
+ return kvm_arch_post_init_vm(kvm);
+}
+
+__weak int kvm_arch_del_vm(int usage_count)
{
return 0;
}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e62240fb8474..90e1dcfc9ace 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -145,6 +145,7 @@ static int kvm_no_compat_open(struct inode *inode, struct file *file)
static int hardware_enable_all(void);
static void hardware_disable_all(void);
static void hardware_disable_nolock(void *junk);
+static void kvm_del_vm(void);

static void kvm_io_bus_destroy(struct kvm_io_bus *bus);

@@ -1215,11 +1216,12 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
if (r)
goto out_err_no_debugfs;

- r = kvm_arch_post_init_vm(kvm);
- if (r)
- goto out_err;
-
mutex_lock(&kvm_lock);
+ r = kvm_arch_add_vm(kvm, kvm_usage_count);
+ if (r) {
+ mutex_unlock(&kvm_lock);
+ goto out_err;
+ }
list_add(&kvm->vm_list, &vm_list);
mutex_unlock(&kvm_lock);

@@ -1239,6 +1241,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
#endif
out_err_no_mmu_notifier:
hardware_disable_all();
+ kvm_del_vm();
out_err_no_disable:
kvm_arch_destroy_vm(kvm);
out_err_no_arch_destroy_vm:
@@ -1319,6 +1322,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
kvm_arch_free_vm(kvm);
preempt_notifier_dec();
hardware_disable_all();
+ kvm_del_vm();
mmdrop(mm);
module_put(kvm_chardev_ops.owner);
}
@@ -5082,6 +5086,15 @@ static void hardware_disable_all(void)
cpus_read_unlock();
}

+static void kvm_del_vm(void)
+{
+ cpus_read_lock();
+ mutex_lock(&kvm_lock);
+ kvm_arch_del_vm(kvm_usage_count);
+ mutex_unlock(&kvm_lock);
+ cpus_read_unlock();
+}
+
static int hardware_enable_all(void)
{
int r = 0;
--
2.25.1