[PATCH 11/44] KVM: x86: Move guts of kvm_arch_init() to standalone helper

From: Sean Christopherson
Date: Wed Nov 02 2022 - 19:20:51 EST


Move the guts of kvm_arch_init() to a new helper, kvm_x86_vendor_init(),
so that VMX can do _all_ arch and vendor initialization before calling
kvm_init(). Calling kvm_init() must be the _very_ last step during init,
as kvm_init() exposes /dev/kvm to userspace, i.e. allows creating VMs.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 3 +++
arch/x86/kvm/svm/svm.c | 23 +++++++++++++++++++++--
arch/x86/kvm/vmx/vmx.c | 9 ++++++++-
arch/x86/kvm/x86.c | 15 +++++++++++++--
4 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 415113dea951..58a7cb8d8e96 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1695,6 +1695,9 @@ extern struct kvm_x86_ops kvm_x86_ops;
#define KVM_X86_OP_OPTIONAL_RET0 KVM_X86_OP
#include <asm/kvm-x86-ops.h>

+int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops);
+void kvm_x86_vendor_exit(void);
+
#define __KVM_HAVE_ARCH_VM_ALLOC
static inline struct kvm *kvm_arch_alloc_vm(void)
{
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d22a809d9233..f48d07bfc3d7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5132,15 +5132,34 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = {

static int __init svm_init(void)
{
+ int r;
+
__unused_size_checks();

- return kvm_init(&svm_init_ops, sizeof(struct vcpu_svm),
- __alignof__(struct vcpu_svm), THIS_MODULE);
+ r = kvm_x86_vendor_init(&svm_init_ops);
+ if (r)
+ return r;
+
+ /*
+ * Common KVM initialization _must_ come last, after this, /dev/kvm is
+ * exposed to userspace!
+ */
+ r = kvm_init(&svm_init_ops, sizeof(struct vcpu_svm),
+ __alignof__(struct vcpu_svm), THIS_MODULE);
+ if (r)
+ goto err_kvm_init;
+
+ return 0;
+
+err_kvm_init:
+ kvm_x86_vendor_exit();
+ return r;
}

static void __exit svm_exit(void)
{
kvm_exit();
+ kvm_x86_vendor_exit();
}

module_init(svm_init)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b3fd4049de01..118d9b29b339 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8501,6 +8501,7 @@ static void vmx_exit(void)
#endif

kvm_exit();
+ kvm_x86_vendor_exit();

hv_cleanup_evmcs();

@@ -8516,13 +8517,17 @@ static int __init vmx_init(void)

hv_setup_evmcs();

+ r = kvm_x86_vendor_init(&vmx_init_ops);
+ if (r)
+ goto err_x86_init;
+
r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx),
__alignof__(struct vcpu_vmx), THIS_MODULE);
if (r)
goto err_kvm_init;

/*
- * Must be called after kvm_init() so enable_ept is properly set
+ * Must be called after common x86 init so enable_ept is properly set
* up. Hand the parameter mitigation value in which was stored in
* the pre module init parser. If no parameter was given, it will
* contain 'auto' which will be turned into the default 'cond'
@@ -8559,6 +8564,8 @@ static int __init vmx_init(void)
err_l1d_flush:
vmx_exit();
err_kvm_init:
+ kvm_x86_vendor_exit();
+err_x86_init:
hv_cleanup_evmcs();
return r;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 40d4bfaa17a4..a0ca401d3cdf 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9272,7 +9272,16 @@ static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)

int kvm_arch_init(void *opaque)
{
- struct kvm_x86_init_ops *ops = opaque;
+ return 0;
+}
+
+void kvm_arch_exit(void)
+{
+
+}
+
+int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
+{
u64 host_pat;
int r;

@@ -9404,8 +9413,9 @@ int kvm_arch_init(void *opaque)
kmem_cache_destroy(x86_emulator_cache);
return r;
}
+EXPORT_SYMBOL_GPL(kvm_x86_vendor_init);

-void kvm_arch_exit(void)
+void kvm_x86_vendor_exit(void)
{
kvm_unregister_perf_callbacks();

@@ -9434,6 +9444,7 @@ void kvm_arch_exit(void)
WARN_ON(static_branch_unlikely(&kvm_xen_enabled.key));
#endif
}
+EXPORT_SYMBOL_GPL(kvm_x86_vendor_exit);

static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
{
--
2.38.1.431.g37b22c650d-goog