Merge branch 'kvm-redo-enable-virt' into HEAD

Register KVM's cpuhp and syscore callbacks when enabling virtualization in
hardware, as the sole purpose of said callbacks is to disable and re-enable
virtualization as needed.

The primary motivation for this series is to simplify dealing with enabling
virtualization for Intel's TDX, which needs to enable virtualization
when kvm-intel.ko is loaded, i.e. long before the first VM is created.

That said, this is a nice cleanup on its own.  By registering the callbacks
on-demand, the callbacks themselves don't need to check kvm_usage_count,
because their very existence implies a non-zero count.

Patch 1 (re)adds a dedicated lock for kvm_usage_count.  This avoids a
lock ordering issue between cpus_read_lock() and kvm_lock.  The lock
ordering issue still exist in very rare cases, and will be fixed for
good by switching vm_list to an (S)RCU-protected list.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/loongarch/kvm/main.c b/arch/loongarch/kvm/main.c
index 844736b99d38..27e9b94c0a0b 100644
--- a/arch/loongarch/kvm/main.c
+++ b/arch/loongarch/kvm/main.c
@@ -261,7 +261,7 @@ long kvm_arch_dev_ioctl(struct file *filp,
 	return -ENOIOCTLCMD;
 }
 
-int kvm_arch_hardware_enable(void)
+int kvm_arch_enable_virtualization_cpu(void)
 {
 	unsigned long env, gcfg = 0;
 
@@ -300,7 +300,7 @@ int kvm_arch_hardware_enable(void)
 	return 0;
 }
 
-void kvm_arch_hardware_disable(void)
+void kvm_arch_disable_virtualization_cpu(void)
 {
 	write_csr_gcfg(0);
 	write_csr_gstat(0);