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-rw-r--r--arch/x86/kvm/vmx/vmx.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 98d732b94..5c1590855 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -407,7 +407,8 @@ static __always_inline void vmx_enable_fb_clear(struct vcpu_vmx *vmx)
static void vmx_update_fb_clear_dis(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
{
- vmx->disable_fb_clear = vmx_fb_clear_ctrl_available;
+ vmx->disable_fb_clear = !cpu_feature_enabled(X86_FEATURE_CLEAR_CPU_BUF) &&
+ vmx_fb_clear_ctrl_available;
/*
* If guest will not execute VERW, there is no need to set FB_CLEAR_DIS
@@ -2469,10 +2470,10 @@ static int kvm_cpu_vmxon(u64 vmxon_pointer)
cr4_set_bits(X86_CR4_VMXE);
- asm_volatile_goto("1: vmxon %[vmxon_pointer]\n\t"
- _ASM_EXTABLE(1b, %l[fault])
- : : [vmxon_pointer] "m"(vmxon_pointer)
- : : fault);
+ asm goto("1: vmxon %[vmxon_pointer]\n\t"
+ _ASM_EXTABLE(1b, %l[fault])
+ : : [vmxon_pointer] "m"(vmxon_pointer)
+ : : fault);
return 0;
fault:
@@ -7120,11 +7121,14 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
{
guest_state_enter_irqoff();
- /* L1D Flush includes CPU buffer clear to mitigate MDS */
+ /*
+ * L1D Flush includes CPU buffer clear to mitigate MDS, but VERW
+ * mitigation for MDS is done late in VMentry and is still
+ * executed in spite of L1D Flush. This is because an extra VERW
+ * should not matter much after the big hammer L1D Flush.
+ */
if (static_branch_unlikely(&vmx_l1d_should_flush))
vmx_l1d_flush(vcpu);
- else if (static_branch_unlikely(&mds_user_clear))
- mds_clear_cpu_buffers();
else if (static_branch_unlikely(&mmio_stale_data_clear) &&
kvm_arch_has_assigned_device(vcpu->kvm))
mds_clear_cpu_buffers();