[PATCH v5 14/44] KVM: VMX: Setup canonical VMCS config prior to kvm_x86_vendor_init()

Sean Christopherson
2025-08-06T19:57:54Z

Setup the golden VMCS config during vmx_init(), before the call to
kvm_x86_vendor_init(), instead of waiting until the callback to do
hardware setup. setup_vmcs_config() only touches VMX state, i.e. doesn't
poke anything in kvm.ko, and has no runtime dependencies beyond
hv_init_evmcs().

Setting the VMCS config early on will allow referencing VMCS and VMX
capabilities at any point during setup, e.g. to check for PERF_GLOBAL_CTRL
save/load support during mediated PMU initialization.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/vmx.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 95765db52992..ed10013dac95 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8335,8 +8335,6 @@ __init int vmx_hardware_setup(void)

vmx_setup_user_return_msrs();

- if (setup_vmcs_config(&vmcs_config, &vmx_capability) < 0)
- return -EIO;

if (boot_cpu_has(X86_FEATURE_NX))
kvm_enable_efer_bits(EFER_NX);
@@ -8560,11 +8558,18 @@ int __init vmx_init(void)
return -EOPNOTSUPP;

/*
- * Note, hv_init_evmcs() touches only VMX knobs, i.e. there's nothing
- * to unwind if a later step fails.
+ * Note, VMCS and eVMCS configuration only touch VMX knobs/variables,
+ * i.e. there's nothing to unwind if a later step fails.
*/
hv_init_evmcs();

+ /*
+ * Parse the VMCS config and VMX capabilities before anything else, so
+ * that the information is available to all setup flows.
+ */
+ if (setup_vmcs_config(&vmcs_config, &vmx_capability) < 0)
+ return -EIO;
+
r = kvm_x86_vendor_init(&vt_init_ops);
if (r)
return r;
--
2.50.1.565.gc32cd1483b-goog