diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2022-06-15 00:16:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-25 12:26:48 +0300 |
| commit | 47ae76fb27398e867980d63789058ff7c4f12a35 (patch) | |
| tree | cb2ef3c7264ec56091d4909cbce3bb97bdc72397 /arch | |
| parent | 5269be9111e2b66572e78647f2e8948f7fc96466 (diff) | |
| download | linux-47ae76fb27398e867980d63789058ff7c4f12a35.tar.xz | |
KVM: VMX: Fix IBRS handling after vmexit
commit bea7e31a5caccb6fe8ed989c065072354f0ecb52 upstream.
For legacy IBRS to work, the IBRS bit needs to be always re-written
after vmexit, even if it's already on.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 296e230f6003..9b520da3f748 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6706,8 +6706,13 @@ void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx, /* * If the guest/host SPEC_CTRL values differ, restore the host value. + * + * For legacy IBRS, the IBRS bit always needs to be written after + * transitioning from a less privileged predictor mode, regardless of + * whether the guest/host values differ. */ - if (vmx->spec_ctrl != hostval) + if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS) || + vmx->spec_ctrl != hostval) native_wrmsrl(MSR_IA32_SPEC_CTRL, hostval); barrier_nospec(); |