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-rw-r--r--arch/x86/include/asm/spec-ctrl.h9
-rw-r--r--arch/x86/kernel/cpu/bugs.c20
-rw-r--r--arch/x86/kvm/svm.c11
-rw-r--r--arch/x86/kvm/vmx.c4
4 files changed, 35 insertions, 9 deletions
diff --git a/arch/x86/include/asm/spec-ctrl.h b/arch/x86/include/asm/spec-ctrl.h
index 0cb49c4564b0..6e2874049afd 100644
--- a/arch/x86/include/asm/spec-ctrl.h
+++ b/arch/x86/include/asm/spec-ctrl.h
@@ -10,10 +10,13 @@
* the guest has, while on VMEXIT we restore the host view. This
* would be easier if SPEC_CTRL were architecturally maskable or
* shadowable for guests but this is not (currently) the case.
- * Takes the guest view of SPEC_CTRL MSR as a parameter.
+ * Takes the guest view of SPEC_CTRL MSR as a parameter and also
+ * the guest's version of VIRT_SPEC_CTRL, if emulated.
*/
-extern void x86_spec_ctrl_set_guest(u64);
-extern void x86_spec_ctrl_restore_host(u64);
+extern void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl,
+ u64 guest_virt_spec_ctrl);
+extern void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl,
+ u64 guest_virt_spec_ctrl);
/* AMD specific Speculative Store Bypass MSR data */
extern u64 x86_amd_ls_cfg_base;
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 7ebd6373fc31..d3afd38f30d1 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -151,7 +151,15 @@ u64 x86_spec_ctrl_get_default(void)
}
EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default);
-void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl)
+/**
+ * x86_spec_ctrl_set_guest - Set speculation control registers for the guest
+ * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
+ * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
+ * (may get translated to MSR_AMD64_LS_CFG bits)
+ *
+ * Avoids writing to the MSR if the content/bits are the same
+ */
+void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
{
u64 host = x86_spec_ctrl_base;
@@ -168,7 +176,15 @@ void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl)
}
EXPORT_SYMBOL_GPL(x86_spec_ctrl_set_guest);
-void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl)
+/**
+ * x86_spec_ctrl_restore_host - Restore host speculation control registers
+ * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
+ * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
+ * (may get translated to MSR_AMD64_LS_CFG bits)
+ *
+ * Avoids writing to the MSR if the content/bits are the same
+ */
+void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
{
u64 host = x86_spec_ctrl_base;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1a7a811118a8..c07dbcc6d449 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -213,6 +213,12 @@ struct vcpu_svm {
} host;
u64 spec_ctrl;
+ /*
+ * Contains guest-controlled bits of VIRT_SPEC_CTRL, which will be
+ * translated into the appropriate L2_CFG bits on the host to
+ * perform speculative control.
+ */
+ u64 virt_spec_ctrl;
u32 *msrpm;
@@ -2060,6 +2066,7 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vcpu->arch.microcode_version = 0x01000065;
svm->spec_ctrl = 0;
+ svm->virt_spec_ctrl = 0;
if (!init_event) {
svm->vcpu.arch.apic_base = APIC_DEFAULT_PHYS_BASE |
@@ -5557,7 +5564,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
* is no need to worry about the conditional branch over the wrmsr
* being speculatively taken.
*/
- x86_spec_ctrl_set_guest(svm->spec_ctrl);
+ x86_spec_ctrl_set_guest(svm->spec_ctrl, svm->virt_spec_ctrl);
asm volatile (
"push %%" _ASM_BP "; \n\t"
@@ -5681,7 +5688,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
svm->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
- x86_spec_ctrl_restore_host(svm->spec_ctrl);
+ x86_spec_ctrl_restore_host(svm->spec_ctrl, svm->virt_spec_ctrl);
reload_tss(vcpu);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 210e1b63d4b5..5d733a03a6fa 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9717,7 +9717,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
* is no need to worry about the conditional branch over the wrmsr
* being speculatively taken.
*/
- x86_spec_ctrl_set_guest(vmx->spec_ctrl);
+ x86_spec_ctrl_set_guest(vmx->spec_ctrl, 0);
vmx->__launched = vmx->loaded_vmcs->launched;
@@ -9865,7 +9865,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
if (unlikely(!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)))
vmx->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL);
- x86_spec_ctrl_restore_host(vmx->spec_ctrl);
+ x86_spec_ctrl_restore_host(vmx->spec_ctrl, 0);
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();