From 40269c03fdbff2171af246795a4c639cb0cf1ed5 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 23 Apr 2024 09:53:28 -0700 Subject: KVM: x86: Explicitly zero kvm_caps during vendor module load 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 Reviewed-by: Xiaoyao Li Message-ID: <20240423165328.2853870-4-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch') 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"); -- cgit v1.2.3