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authorThomas Gleixner <tglx@linutronix.de>2019-02-27 12:48:14 +0100
committerThomas Gleixner <tglx@linutronix.de>2019-03-06 21:52:13 +0100
commit650b68a0622f933444a6d66936abb3103029413b (patch)
tree04546d2bf324a808655a05e15cad21aacf779391 /arch/x86/kvm/vmx/vmx.c
parentx86/speculation/mds: Clear CPU buffers on exit to user (diff)
downloadlinux-650b68a0622f933444a6d66936abb3103029413b.tar.xz
linux-650b68a0622f933444a6d66936abb3103029413b.zip
x86/kvm/vmx: Add MDS protection when L1D Flush is not active
CPUs which are affected by L1TF and MDS mitigate MDS with the L1D Flush on VMENTER when updated microcode is installed. If a CPU is not affected by L1TF or if the L1D Flush is not in use, then MDS mitigation needs to be invoked explicitly. For these cases, follow the host mitigation state and invoke the MDS mitigation before VMENTER. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/vmx.c')
-rw-r--r--arch/x86/kvm/vmx/vmx.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 30a6bcd735ec..544bd24a9c1e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6369,8 +6369,11 @@ static void __vmx_vcpu_run(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
evmcs_rsp = static_branch_unlikely(&enable_evmcs) ?
(unsigned long)&current_evmcs->host_rsp : 0;
+ /* 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))
+ mds_clear_cpu_buffers();
asm(
/* Store host registers */