diff options
| author | Yosry Ahmed <yosry.ahmed@linux.dev> | 2025-02-27 01:27:10 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-02-27 10:57:20 +0100 |
| commit | 80dacb080461edfc1d854721ee6933a4cfa3b602 (patch) | |
| tree | 4479b3c8bf6184f2c4a28ba5efa09b262c021a05 /arch/x86/kvm/svm | |
| parent | bd9a8542ceccce1b1d5d5fd5e47be57fe42f9bb9 (diff) | |
x86/bugs: Use a static branch to guard IBPB on vCPU switch
Instead of using X86_FEATURE_USE_IBPB to guard the IBPB execution in KVM
when a new vCPU is loaded, introduce a static branch, similar to
switch_mm_*_ibpb.
This makes it obvious in spectre_v2_user_select_mitigation() what
exactly is being toggled, instead of the unclear X86_FEATURE_USE_IBPB
(which will be shortly removed). It also provides more fine-grained
control, making it simpler to change/add paths that control the IBPB in
the vCPU switch path without affecting other IBPBs.
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250227012712.3193063-5-yosry.ahmed@linux.dev
Diffstat (limited to 'arch/x86/kvm/svm')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 57222c3b5659..a73875ffbc3d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1566,7 +1566,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) sd->current_vmcb = svm->vmcb; if (!cpu_feature_enabled(X86_FEATURE_IBPB_ON_VMEXIT) && - cpu_feature_enabled(X86_FEATURE_USE_IBPB)) + static_branch_likely(&switch_vcpu_ibpb)) indirect_branch_prediction_barrier(); } if (kvm_vcpu_apicv_active(vcpu)) |