Zero out all of kvm_caps when loading a new vendor module to ensure that
KVM can't inadvertently rely on global initialization of a field, and add
a comment above the definition of kvm_caps to call out that all fields
needs to be explicitly computed during vendor module load.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 44ce187bad89..8f3979d5fc80 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -92,6 +92,11 @@
#define MAX_IO_MSRS 256
#define KVM_MAX_MCE_BANKS 32
+/*
+ * Note, kvm_caps fields should *never* have default values, all fields must be
+ * recomputed from scratch during vendor module load, e.g. to account for a
+ * vendor module being reloaded with different module parameters.
+ */
struct kvm_caps kvm_caps __read_mostly;
EXPORT_SYMBOL_GPL(kvm_caps);
@@ -9755,6 +9760,8 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
return -EIO;
}
+ memset(&kvm_caps, 0, sizeof(kvm_caps));
+
x86_emulator_cache = kvm_alloc_emulator_cache();
if (!x86_emulator_cache) {
pr_err("failed to allocate cache for x86 emulator\n");
--
2.44.0.769.g3c40516874-goog
