diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-12-13 06:09:07 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-01-24 10:36:26 -0800 |
| commit | 8578f59657c505982e1d05232272c6bf304cf8aa (patch) | |
| tree | 9ef4dd4d31fb83a473583f27f0ffe31c3aaceb52 | |
| parent | fc9465be8aad2042978590d44c01350534c1ac11 (diff) | |
KVM: VMX: Allow VM-Fail path of VMREAD helper to be instrumented
Allow instrumentation in the VM-Fail path of __vmcs_readl() so that the
helper can be used in noinstr functions, e.g. to get the exit reason in
vmx_vcpu_enter_exit() in order to handle NMI VM-Exits in the noinstr
section. While allowing instrumentation isn't technically safe, KVM has
much bigger problems if VMREAD fails in a noinstr section.
Note, all other VMX instructions also allow instrumentation in their
VM-Fail paths for similar reasons, VMREAD was simply omitted by commit
3ebccdf373c2 ("x86/kvm/vmx: Move guest enter/exit into .noinstr.text")
because VMREAD wasn't used in a noinstr section at the time.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221213060912.654668-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kvm/vmx/vmx_ops.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/vmx_ops.h b/arch/x86/kvm/vmx/vmx_ops.h index a5282014616c..db95bde52998 100644 --- a/arch/x86/kvm/vmx/vmx_ops.h +++ b/arch/x86/kvm/vmx/vmx_ops.h @@ -100,8 +100,10 @@ static __always_inline unsigned long __vmcs_readl(unsigned long field) return value; do_fail: + instrumentation_begin(); WARN_ONCE(1, KBUILD_MODNAME ": vmread failed: field=%lx\n", field); pr_warn_ratelimited(KBUILD_MODNAME ": vmread failed: field=%lx\n", field); + instrumentation_end(); return 0; do_exception: |