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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-02-14 03:22:24 +0100 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2024-02-20 01:31:49 +0100 |
| commit | 6613d82e617dd7eb8b0c40b2fe3acea655b1d611 (patch) | |
| tree | 12b811a5b6d4013fea0cc31bc2f79036bd0d138d /arch/x86/kvm | |
| parent | x86/entry_32: Add VERW just before userspace transition (diff) | |
| download | linux-6613d82e617dd7eb8b0c40b2fe3acea655b1d611.tar.xz linux-6613d82e617dd7eb8b0c40b2fe3acea655b1d611.zip | |
x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key
The VERW mitigation at exit-to-user is enabled via a static branch
mds_user_clear. This static branch is never toggled after boot, and can
be safely replaced with an ALTERNATIVE() which is convenient to use in
asm.
Switch to ALTERNATIVE() to use the VERW mitigation late in exit-to-user
path. Also remove the now redundant VERW in exc_nmi() and
arch_exit_to_user_mode().
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20240213-delay-verw-v8-4-a6216d83edb7%40linux.intel.com
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 1111d9d08903..db8a5fe7edf6 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7227,7 +7227,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, /* L1D Flush includes CPU buffer clear to mitigate MDS */ if (static_branch_unlikely(&vmx_l1d_should_flush)) vmx_l1d_flush(vcpu); - else if (static_branch_unlikely(&mds_user_clear)) + else if (cpu_feature_enabled(X86_FEATURE_CLEAR_CPU_BUF)) mds_clear_cpu_buffers(); else if (static_branch_unlikely(&mmio_stale_data_clear) && kvm_arch_has_assigned_device(vcpu->kvm)) |