KVM: VMX: Add cpu consistency check

All the physical CPUs on the board should support the same VMX feature
set.  Add check_processor_compatibility to kvm_arch_ops for the consistency
check.

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

4 files changed, 50 insertions, 18 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 7a34706f42be..cfda3abff89a 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -420,6 +420,7 @@ struct kvm_arch_ops {
         int (*disabled_by_bios)(void);             /* __init */
         void (*hardware_enable)(void *dummy);      /* __init */
         void (*hardware_disable)(void *dummy);
+        void (*check_processor_compatibility)(void *rtn);
         int (*hardware_setup)(void);               /* __init */
         void (*hardware_unsetup)(void);            /* __exit */
 
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 5dee3024579d..2be6b1ca1a06 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -3102,6 +3102,7 @@ int kvm_init_arch(struct kvm_arch_ops *ops, unsigned int vcpu_size,
                   struct module *module)
 {
         int r;
+        int cpu;
 
         if (kvm_arch_ops) {
                 printk(KERN_ERR "kvm: already loaded the other module\n");
@@ -3123,6 +3124,14 @@ int kvm_init_arch(struct kvm_arch_ops *ops, unsigned int vcpu_size,
         if (r < 0)
                 goto out;
 
+        for_each_online_cpu(cpu) {
+                smp_call_function_single(cpu,
+                                kvm_arch_ops->check_processor_compatibility,
+                                &r, 0, 1);
+                if (r < 0)
+                        goto out_free_0;
+        }
+
         on_each_cpu(hardware_enable, NULL, 0, 1);
         r = register_cpu_notifier(&kvm_cpu_notifier);
         if (r)
@@ -3169,6 +3178,7 @@ out_free_2:
         unregister_cpu_notifier(&kvm_cpu_notifier);
 out_free_1:
         on_each_cpu(hardware_disable, NULL, 0, 1);
+out_free_0:
         kvm_arch_ops->hardware_unsetup();
 out:
         kvm_arch_ops = NULL;
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 5277084f3a35..827bc2774e73 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1798,11 +1798,17 @@ svm_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall)
         hypercall[3] = 0xc3;
 }
 
+static void svm_check_processor_compat(void *rtn)
+{
+        *(int *)rtn = 0;
+}
+
 static struct kvm_arch_ops svm_arch_ops = {
         .cpu_has_kvm_support = has_svm,
         .disabled_by_bios = is_disabled,
         .hardware_setup = svm_hardware_setup,
         .hardware_unsetup = svm_hardware_unsetup,
+        .check_processor_compatibility = svm_check_processor_compat,
         .hardware_enable = svm_hardware_enable,
         .hardware_disable = svm_hardware_disable,
 
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 2b30274656f4..c4b8bfea4410 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -840,13 +840,13 @@ static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt,
 
         /* Ensure minimum (required) set of control bits are supported. */
         if (ctl_min & ~ctl)
-                return -1;
+                return -EIO;
 
         *result = ctl;
         return 0;
 }
 
-static __init int setup_vmcs_config(void)
+static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 {
         u32 vmx_msr_low, vmx_msr_high;
         u32 min, opt;
@@ -859,7 +859,7 @@ static __init int setup_vmcs_config(void)
         opt = 0;
         if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS,
                                 &_pin_based_exec_control) < 0)
-                return -1;
+                return -EIO;
 
         min = CPU_BASED_HLT_EXITING |
 #ifdef CONFIG_X86_64
@@ -872,7 +872,7 @@ static __init int setup_vmcs_config(void)
         opt = 0;
         if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PROCBASED_CTLS,
                                 &_cpu_based_exec_control) < 0)
-                return -1;
+                return -EIO;
 
         min = 0;
 #ifdef CONFIG_X86_64
@@ -881,37 +881,37 @@ static __init int setup_vmcs_config(void)
         opt = 0;
         if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS,
                                 &_vmexit_control) < 0)
-                return -1;
+                return -EIO;
 
         min = opt = 0;
         if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS,
                                 &_vmentry_control) < 0)
-                return -1;
+                return -EIO;
 
         rdmsr(MSR_IA32_VMX_BASIC, vmx_msr_low, vmx_msr_high);
 
         /* IA-32 SDM Vol 3B: VMCS size is never greater than 4kB. */
         if ((vmx_msr_high & 0x1fff) > PAGE_SIZE)
-                return -1;
+                return -EIO;
 
 #ifdef CONFIG_X86_64
         /* IA-32 SDM Vol 3B: 64-bit CPUs always have VMX_BASIC_MSR[48]==0. */
         if (vmx_msr_high & (1u<<16))
-                return -1;
+                return -EIO;
 #endif
 
         /* Require Write-Back (WB) memory type for VMCS accesses. */
         if (((vmx_msr_high >> 18) & 15) != 6)
-                return -1;
+                return -EIO;
 
-        vmcs_config.size = vmx_msr_high & 0x1fff;
-        vmcs_config.order = get_order(vmcs_config.size);
-        vmcs_config.revision_id = vmx_msr_low;
+        vmcs_conf->size = vmx_msr_high & 0x1fff;
+        vmcs_conf->order = get_order(vmcs_config.size);
+        vmcs_conf->revision_id = vmx_msr_low;
 
-        vmcs_config.pin_based_exec_ctrl = _pin_based_exec_control;
-        vmcs_config.cpu_based_exec_ctrl = _cpu_based_exec_control;
-        vmcs_config.vmexit_ctrl         = _vmexit_control;
-        vmcs_config.vmentry_ctrl        = _vmentry_control;
+        vmcs_conf->pin_based_exec_ctrl = _pin_based_exec_control;
+        vmcs_conf->cpu_based_exec_ctrl = _cpu_based_exec_control;
+        vmcs_conf->vmexit_ctrl         = _vmexit_control;
+        vmcs_conf->vmentry_ctrl        = _vmentry_control;
 
         return 0;
 }
@@ -971,8 +971,8 @@ static __init int alloc_kvm_area(void)
 
 static __init int hardware_setup(void)
 {
-        if (setup_vmcs_config() < 0)
-                return -1;
+        if (setup_vmcs_config(&vmcs_config) < 0)
+                return -EIO;
         return alloc_kvm_area();
 }
 
@@ -2414,11 +2414,26 @@ free_vcpu:
         return ERR_PTR(err);
 }
 
+static void __init vmx_check_processor_compat(void *rtn)
+{
+        struct vmcs_config vmcs_conf;
+
+        *(int *)rtn = 0;
+        if (setup_vmcs_config(&vmcs_conf) < 0)
+                *(int *)rtn = -EIO;
+        if (memcmp(&vmcs_config, &vmcs_conf, sizeof(struct vmcs_config)) != 0) {
+                printk(KERN_ERR "kvm: CPU %d feature inconsistency!\n",
+                                smp_processor_id());
+                *(int *)rtn = -EIO;
+        }
+}
+
 static struct kvm_arch_ops vmx_arch_ops = {
         .cpu_has_kvm_support = cpu_has_kvm_support,
         .disabled_by_bios = vmx_disabled_by_bios,
         .hardware_setup = hardware_setup,
         .hardware_unsetup = hardware_unsetup,
+        .check_processor_compatibility = vmx_check_processor_compat,
         .hardware_enable = hardware_enable,
         .hardware_disable = hardware_disable,