Merge tag 'x86-bugs-2022-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-block.git] / arch / x86 / kvm / vmx / vmx.c

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9bd86ecccdab56d455fdcc30e7fab6039b127eee..6df17ef81905f5a14f60ab0eda9ea8787b81b53c 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -229,6 +229,9 @@ static const struct {
 #define L1D_CACHE_ORDER 4
 static void *vmx_l1d_flush_pages;
 
+/* Control for disabling CPU Fill buffer clear */
+static bool __read_mostly vmx_fb_clear_ctrl_available;
+
 static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf)
 {
        struct page *page;
@@ -360,6 +363,60 @@ static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
        return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
 }
 
+static void vmx_setup_fb_clear_ctrl(void)
+{
+       u64 msr;
+
+       if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES) &&
+           !boot_cpu_has_bug(X86_BUG_MDS) &&
+           !boot_cpu_has_bug(X86_BUG_TAA)) {
+               rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr);
+               if (msr & ARCH_CAP_FB_CLEAR_CTRL)
+                       vmx_fb_clear_ctrl_available = true;
+       }
+}
+
+static __always_inline void vmx_disable_fb_clear(struct vcpu_vmx *vmx)
+{
+       u64 msr;
+
+       if (!vmx->disable_fb_clear)
+               return;
+
+       rdmsrl(MSR_IA32_MCU_OPT_CTRL, msr);
+       msr |= FB_CLEAR_DIS;
+       wrmsrl(MSR_IA32_MCU_OPT_CTRL, msr);
+       /* Cache the MSR value to avoid reading it later */
+       vmx->msr_ia32_mcu_opt_ctrl = msr;
+}
+
+static __always_inline void vmx_enable_fb_clear(struct vcpu_vmx *vmx)
+{
+       if (!vmx->disable_fb_clear)
+               return;
+
+       vmx->msr_ia32_mcu_opt_ctrl &= ~FB_CLEAR_DIS;
+       wrmsrl(MSR_IA32_MCU_OPT_CTRL, vmx->msr_ia32_mcu_opt_ctrl);
+}
+
+static void vmx_update_fb_clear_dis(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx)
+{
+       vmx->disable_fb_clear = vmx_fb_clear_ctrl_available;
+
+       /*
+        * If guest will not execute VERW, there is no need to set FB_CLEAR_DIS
+        * at VMEntry. Skip the MSR read/write when a guest has no use case to
+        * execute VERW.
+        */
+       if ((vcpu->arch.arch_capabilities & ARCH_CAP_FB_CLEAR) ||
+          ((vcpu->arch.arch_capabilities & ARCH_CAP_MDS_NO) &&
+           (vcpu->arch.arch_capabilities & ARCH_CAP_TAA_NO) &&
+           (vcpu->arch.arch_capabilities & ARCH_CAP_PSDP_NO) &&
+           (vcpu->arch.arch_capabilities & ARCH_CAP_FBSDP_NO) &&
+           (vcpu->arch.arch_capabilities & ARCH_CAP_SBDR_SSDP_NO)))
+               vmx->disable_fb_clear = false;
+}
+
 static const struct kernel_param_ops vmentry_l1d_flush_ops = {
        .set = vmentry_l1d_flush_set,
        .get = vmentry_l1d_flush_get,
@@ -2252,6 +2309,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
                        ret = kvm_set_msr_common(vcpu, msr_info);
        }
 
+       /* FB_CLEAR may have changed, also update the FB_CLEAR_DIS behavior */
+       if (msr_index == MSR_IA32_ARCH_CAPABILITIES)
+               vmx_update_fb_clear_dis(vcpu, vmx);
+
        return ret;
 }
 
@@ -4553,6 +4614,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
        kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu);
 
        vpid_sync_context(vmx->vpid);
+
+       vmx_update_fb_clear_dis(vcpu, vmx);
 }
 
 static void vmx_enable_irq_window(struct kvm_vcpu *vcpu)
@@ -6772,6 +6835,11 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
                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();
+
+       vmx_disable_fb_clear(vmx);
 
        if (vcpu->arch.cr2 != native_read_cr2())
                native_write_cr2(vcpu->arch.cr2);
@@ -6781,6 +6849,8 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
 
        vcpu->arch.cr2 = native_read_cr2();
 
+       vmx_enable_fb_clear(vmx);
+
        guest_state_exit_irqoff();
 }
 
@@ -8212,6 +8282,8 @@ static int __init vmx_init(void)
                return r;
        }
 
+       vmx_setup_fb_clear_ctrl();
+
        for_each_possible_cpu(cpu) {
                INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu));