diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-07-21 16:56:36 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-07-29 11:05:26 -0400 |
| commit | c20d403fd04c20959b7e6669868372f433947e5f (patch) | |
| tree | e4c0fc8d9a6024fc4b5cf2234a27e251674733e4 /arch/x86/kvm/vmx/vmx.c | |
| parent | 5e1fe4a21c0c2a69419d97d62d3213e8f843920d (diff) | |
KVM: VMX: Make VMREAD error path play nice with noinstr
Mark vmread_error_trampoline() as noinstr, and add a second trampoline
for the CONFIG_CC_HAS_ASM_GOTO_OUTPUT=n case to enable instrumentation
when handling VM-Fail on VMREAD. VMREAD is used in various noinstr
flows, e.g. immediately after VM-Exit, and objtool rightly complains that
the call to the error trampoline leaves a no-instrumentation section
without annotating that it's safe to do so.
vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0xc9:
call to vmread_error_trampoline() leaves .noinstr.text section
Note, strictly speaking, enabling instrumentation in the VM-Fail path
isn't exactly safe, but if VMREAD fails the kernel/system is likely hosed
anyways, and logging that there is a fatal error is more important than
*maybe* encountering slightly unsafe instrumentation.
Reported-by: Su Hui <suhui@nfschina.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230721235637.2345403-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 3c5a13f054fc..0dd4612b0ca2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -441,13 +441,23 @@ do { \ pr_warn_ratelimited(fmt); \ } while (0) -void vmread_error(unsigned long field, bool fault) +noinline void vmread_error(unsigned long field) { - if (fault) + vmx_insn_failed("vmread failed: field=%lx\n", field); +} + +#ifndef CONFIG_CC_HAS_ASM_GOTO_OUTPUT +noinstr void vmread_error_trampoline2(unsigned long field, bool fault) +{ + if (fault) { kvm_spurious_fault(); - else - vmx_insn_failed("vmread failed: field=%lx\n", field); + } else { + instrumentation_begin(); + vmread_error(field); + instrumentation_end(); + } } +#endif noinline void vmwrite_error(unsigned long field, unsigned long value) { |