From: Ashok Raj <ashok....@intel.com>

On Intel platforms, this patch adds LMCE to KVM MCE supported
capabilities and handles guest access to LMCE related MSRs.

Signed-off-by: Ashok Raj <ashok....@intel.com>
[Haozhong: macro KVM_MCE_CAP_SUPPORTED => variable kvm_mce_cap_supported
           Only enable LMCE on Intel platform
           Check MSR_IA32_FEATURE_CONTROL when handling guest
             access to MSR_IA32_MCG_EXT_CTL]
Signed-off-by: Haozhong Zhang <haozhong.zh...@intel.com>
---
 arch/x86/include/asm/kvm_host.h |  5 +++++
 arch/x86/kvm/vmx.c              | 36 +++++++++++++++++++++++++++++++++++-
 arch/x86/kvm/x86.c              | 15 +++++++++------
 3 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e0fbe7e..75defa6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -598,6 +598,7 @@ struct kvm_vcpu_arch {
        u64 mcg_cap;
        u64 mcg_status;
        u64 mcg_ctl;
+       u64 mcg_ext_ctl;
        u64 *mce_banks;
 
        /* Cache MMIO info */
@@ -1005,6 +1006,8 @@ struct kvm_x86_ops {
        int (*update_pi_irte)(struct kvm *kvm, unsigned int host_irq,
                              uint32_t guest_irq, bool set);
        void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu);
+
+       void (*setup_mce)(struct kvm_vcpu *vcpu);
 };
 
 struct kvm_arch_async_pf {
@@ -1077,6 +1080,8 @@ extern u8   kvm_tsc_scaling_ratio_frac_bits;
 /* maximum allowed value of TSC scaling ratio */
 extern u64  kvm_max_tsc_scaling_ratio;
 
+extern u64 kvm_mce_cap_supported;
+
 enum emulation_result {
        EMULATE_DONE,         /* no further processing */
        EMULATE_USER_EXIT,    /* kvm_run ready for userspace exit */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1dc89c5..42db42e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -638,7 +638,7 @@ static struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu 
*vcpu)
  * feature_control_valid_bits_add/del(), so it's not included here.
  */
 #define FEATURE_CONTROL_MAX_VALID_BITS \
-       FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX
+       (FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX | FEATURE_CONTROL_LMCE)
 
 static void feature_control_valid_bits_add(struct kvm_vcpu *vcpu, uint64_t 
bits)
 {
@@ -2905,6 +2905,15 @@ static inline bool vmx_feature_control_msr_valid(struct 
kvm_vcpu *vcpu,
        return valid_bits && !(val & ~valid_bits);
 }
 
+static inline bool vmx_mcg_ext_ctrl_msr_present(struct kvm_vcpu *vcpu,
+                                               bool host_initiated)
+{
+       return (vcpu->arch.mcg_cap & MCG_LMCE_P) &&
+               (host_initiated ||
+                (to_vmx(vcpu)->msr_ia32_feature_control &
+                 FEATURE_CONTROL_LMCE));
+}
+
 /*
  * Reads an msr value (of 'msr_index') into 'pdata'.
  * Returns 0 on success, non-0 otherwise.
@@ -2946,6 +2955,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct 
msr_data *msr_info)
                        return 1;
                msr_info->data = vmcs_read64(GUEST_BNDCFGS);
                break;
+       case MSR_IA32_MCG_EXT_CTL:
+               if (!vmx_mcg_ext_ctrl_msr_present(vcpu,
+                                                 msr_info->host_initiated))
+                       return 1;
+               msr_info->data = vcpu->arch.mcg_ext_ctl;
+               break;
        case MSR_IA32_FEATURE_CONTROL:
                if (!vmx_feature_control_msr_valid(vcpu, 0))
                        return 1;
@@ -3039,6 +3054,13 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct 
msr_data *msr_info)
        case MSR_IA32_TSC_ADJUST:
                ret = kvm_set_msr_common(vcpu, msr_info);
                break;
+       case MSR_IA32_MCG_EXT_CTL:
+               if (!vmx_mcg_ext_ctrl_msr_present(vcpu,
+                                                 msr_info->host_initiated) ||
+                   (data & ~MCG_EXT_CTL_LMCE_EN))
+                       return 1;
+               vcpu->arch.mcg_ext_ctl = data;
+               break;
        case MSR_IA32_FEATURE_CONTROL:
                if (!vmx_feature_control_msr_valid(vcpu, data) ||
                    (to_vmx(vcpu)->msr_ia32_feature_control &
@@ -6433,6 +6455,8 @@ static __init int hardware_setup(void)
 
        kvm_set_posted_intr_wakeup_handler(wakeup_handler);
 
+       kvm_mce_cap_supported |= MCG_LMCE_P;
+
        return alloc_kvm_area();
 
 out8:
@@ -10950,6 +10974,14 @@ out:
        return ret;
 }
 
+static void vmx_setup_mce(struct kvm_vcpu *vcpu)
+{
+       if (vcpu->arch.mcg_cap & MCG_LMCE_P)
+               feature_control_valid_bits_add(vcpu, FEATURE_CONTROL_LMCE);
+       else
+               feature_control_valid_bits_del(vcpu, FEATURE_CONTROL_LMCE);
+}
+
 static struct kvm_x86_ops vmx_x86_ops = {
        .cpu_has_kvm_support = cpu_has_kvm_support,
        .disabled_by_bios = vmx_disabled_by_bios,
@@ -11074,6 +11106,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
        .pmu_ops = &intel_pmu_ops,
 
        .update_pi_irte = vmx_update_pi_irte,
+
+       .setup_mce = vmx_setup_mce,
 };
 
 static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bf22721..5bf76ab 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -70,7 +70,8 @@
 
 #define MAX_IO_MSRS 256
 #define KVM_MAX_MCE_BANKS 32
-#define KVM_MCE_CAP_SUPPORTED (MCG_CTL_P | MCG_SER_P)
+u64 __read_mostly kvm_mce_cap_supported = MCG_CTL_P | MCG_SER_P;
+EXPORT_SYMBOL_GPL(kvm_mce_cap_supported);
 
 #define emul_to_vcpu(ctxt) \
        container_of(ctxt, struct kvm_vcpu, arch.emulate_ctxt)
@@ -983,6 +984,7 @@ static u32 emulated_msrs[] = {
        MSR_IA32_MISC_ENABLE,
        MSR_IA32_MCG_STATUS,
        MSR_IA32_MCG_CTL,
+       MSR_IA32_MCG_EXT_CTL,
        MSR_IA32_SMBASE,
 };
 
@@ -2684,11 +2686,9 @@ long kvm_arch_dev_ioctl(struct file *filp,
                break;
        }
        case KVM_X86_GET_MCE_CAP_SUPPORTED: {
-               u64 mce_cap;
-
-               mce_cap = KVM_MCE_CAP_SUPPORTED;
                r = -EFAULT;
-               if (copy_to_user(argp, &mce_cap, sizeof mce_cap))
+               if (copy_to_user(argp, &kvm_mce_cap_supported,
+                                sizeof(kvm_mce_cap_supported)))
                        goto out;
                r = 0;
                break;
@@ -2866,7 +2866,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu 
*vcpu,
        r = -EINVAL;
        if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS)
                goto out;
-       if (mcg_cap & ~(KVM_MCE_CAP_SUPPORTED | 0xff | 0xff0000))
+       if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000))
                goto out;
        r = 0;
        vcpu->arch.mcg_cap = mcg_cap;
@@ -2876,6 +2876,9 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu 
*vcpu,
        /* Init IA32_MCi_CTL to all 1s */
        for (bank = 0; bank < bank_num; bank++)
                vcpu->arch.mce_banks[bank*4] = ~(u64)0;
+
+       if (kvm_x86_ops->setup_mce)
+               kvm_x86_ops->setup_mce(vcpu);
 out:
        return r;
 }
-- 
2.9.0

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