From: Josh Poimboeuf jpoimboe@kernel.org
stable inclusion from stable-v5.10.133 commit 47ae76fb27398e867980d63789058ff7c4f12a35 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5PTAS CVE: CVE-2022-29900,CVE-2022-23816,CVE-2022-29901
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Signed-off-by: Lin Yujun linyujun809@huawei.com Reviewed-by: Zhang Jianhua chris.zjh@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/x86/kvm/vmx/vmx.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index b03f72c2f3c8..31dbc24ec04a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6834,8 +6834,13 @@ 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();