KVM: VMX: Enable Virtual Processor Identification (VPID)

To allow TLB entries to be retained across VM entry and VM exit, the VMM
can now identify distinct address spaces through a new virtual-processor ID
(VPID) field of the VMCS.

[avi: drop vpid_sync_all()]
[avi: add "cc" to asm constraints]

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

3 files changed, 82 insertions, 5 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8e1462880d1f..1157e8a4059b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -37,6 +37,9 @@ MODULE_LICENSE("GPL");
 static int bypass_guest_pf = 1;
 module_param(bypass_guest_pf, bool, 0);
 
+static int enable_vpid = 1;
+module_param(enable_vpid, bool, 0);
+
 struct vmcs {
         u32 revision_id;
         u32 abort;
@@ -71,6 +74,7 @@ struct vcpu_vmx {
                         unsigned rip;
                 } irq;
         } rmode;
+        int vpid;
 };
 
 static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
@@ -86,6 +90,9 @@ static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
 static struct page *vmx_io_bitmap_a;
 static struct page *vmx_io_bitmap_b;
 
+static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
+static DEFINE_SPINLOCK(vmx_vpid_lock);
+
 static struct vmcs_config {
         int size;
         int order;
@@ -204,6 +211,12 @@ static inline int vm_need_virtualize_apic_accesses(struct kvm *kvm)
                 (irqchip_in_kernel(kvm)));
 }
 
+static inline int cpu_has_vmx_vpid(void)
+{
+        return (vmcs_config.cpu_based_2nd_exec_ctrl &
+                SECONDARY_EXEC_ENABLE_VPID);
+}
+
 static int __find_msr_index(struct vcpu_vmx *vmx, u32 msr)
 {
         int i;
@@ -214,6 +227,20 @@ static int __find_msr_index(struct vcpu_vmx *vmx, u32 msr)
         return -1;
 }
 
+static inline void __invvpid(int ext, u16 vpid, gva_t gva)
+{
+    struct {
+        u64 vpid : 16;
+        u64 rsvd : 48;
+        u64 gva;
+    } operand = { vpid, 0, gva };
+
+    asm volatile (ASM_VMX_INVVPID
+                  /* CF==1 or ZF==1 --> rc = -1 */
+                  "; ja 1f ; ud2 ; 1:"
+                  : : "a"(&operand), "c"(ext) : "cc", "memory");
+}
+
 static struct kvm_msr_entry *find_msr_entry(struct vcpu_vmx *vmx, u32 msr)
 {
         int i;
@@ -257,6 +284,14 @@ static void vcpu_clear(struct vcpu_vmx *vmx)
         vmx->launched = 0;
 }
 
+static inline void vpid_sync_vcpu_all(struct vcpu_vmx *vmx)
+{
+        if (vmx->vpid == 0)
+                return;
+
+        __invvpid(VMX_VPID_EXTENT_SINGLE_CONTEXT, vmx->vpid, 0);
+}
+
 static unsigned long vmcs_readl(unsigned long field)
 {
         unsigned long value;
@@ -490,6 +525,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
         if (vcpu->cpu != cpu) {
                 vcpu_clear(vmx);
                 kvm_migrate_apic_timer(vcpu);
+                vpid_sync_vcpu_all(vmx);
         }
 
         if (per_cpu(current_vmcs, cpu) != vmx->vmcs) {
@@ -971,7 +1007,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
         if (_cpu_based_exec_control & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS) {
                 min = 0;
                 opt = SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
-                        SECONDARY_EXEC_WBINVD_EXITING;
+                        SECONDARY_EXEC_WBINVD_EXITING |
+                        SECONDARY_EXEC_ENABLE_VPID;
                 if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PROCBASED_CTLS2,
                                         &_cpu_based_2nd_exec_control) < 0)
                         return -EIO;
@@ -1239,6 +1276,11 @@ static void exit_lmode(struct kvm_vcpu *vcpu)
 
 #endif
 
+static void vmx_flush_tlb(struct kvm_vcpu *vcpu)
+{
+        vpid_sync_vcpu_all(to_vmx(vcpu));
+}
+
 static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
 {
         vcpu->arch.cr4 &= KVM_GUEST_CR4_MASK;
@@ -1275,6 +1317,7 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 
 static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 {
+        vmx_flush_tlb(vcpu);
         vmcs_writel(GUEST_CR3, cr3);
         if (vcpu->arch.cr0 & X86_CR0_PE)
                 vmx_fpu_deactivate(vcpu);
@@ -1494,6 +1537,22 @@ out:
         return r;
 }
 
+static void allocate_vpid(struct vcpu_vmx *vmx)
+{
+        int vpid;
+
+        vmx->vpid = 0;
+        if (!enable_vpid || !cpu_has_vmx_vpid())
+                return;
+        spin_lock(&vmx_vpid_lock);
+        vpid = find_first_zero_bit(vmx_vpid_bitmap, VMX_NR_VPIDS);
+        if (vpid < VMX_NR_VPIDS) {
+                vmx->vpid = vpid;
+                __set_bit(vpid, vmx_vpid_bitmap);
+        }
+        spin_unlock(&vmx_vpid_lock);
+}
+
 /*
  * Sets up the vmcs for emulated real mode.
  */
@@ -1532,6 +1591,8 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
                 if (!vm_need_virtualize_apic_accesses(vmx->vcpu.kvm))
                         exec_control &=
                                 ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+                if (vmx->vpid == 0)
+                        exec_control &= ~SECONDARY_EXEC_ENABLE_VPID;
                 vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
         }
 
@@ -1704,6 +1765,9 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
                 vmcs_write64(APIC_ACCESS_ADDR,
                              page_to_phys(vmx->vcpu.kvm->arch.apic_access_page));
 
+        if (vmx->vpid != 0)
+                vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid);
+
         vmx->vcpu.arch.cr0 = 0x60000010;
         vmx_set_cr0(&vmx->vcpu, vmx->vcpu.arch.cr0); /* enter rmode */
         vmx_set_cr4(&vmx->vcpu, 0);
@@ -1713,6 +1777,8 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
         vmx_fpu_activate(&vmx->vcpu);
         update_exception_bitmap(&vmx->vcpu);
 
+        vpid_sync_vcpu_all(vmx);
+
         return 0;
 
 out:
@@ -2221,10 +2287,6 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
         return 0;
 }
 
-static void vmx_flush_tlb(struct kvm_vcpu *vcpu)
-{
-}
-
 static void update_tpr_threshold(struct kvm_vcpu *vcpu)
 {
         int max_irr, tpr;
@@ -2489,6 +2551,10 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+        spin_lock(&vmx_vpid_lock);
+        if (vmx->vpid != 0)
+                __clear_bit(vmx->vpid, vmx_vpid_bitmap);
+        spin_unlock(&vmx_vpid_lock);
         vmx_free_vmcs(vcpu);
         kfree(vmx->host_msrs);
         kfree(vmx->guest_msrs);
@@ -2505,6 +2571,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
         if (!vmx)
                 return ERR_PTR(-ENOMEM);
 
+        allocate_vpid(vmx);
+
         err = kvm_vcpu_init(&vmx->vcpu, kvm, id);
         if (err)
                 goto free_vcpu;
@@ -2652,6 +2720,8 @@ static int __init vmx_init(void)
         memset(iova, 0xff, PAGE_SIZE);
         kunmap(vmx_io_bitmap_b);
 
+        set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
+
         r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), THIS_MODULE);
         if (r)
                 goto out1;
diff --git a/arch/x86/kvm/vmx.h b/arch/x86/kvm/vmx.h
index d52ae8d7303d..436ce0f29092 100644
--- a/arch/x86/kvm/vmx.h
+++ b/arch/x86/kvm/vmx.h
@@ -49,6 +49,7 @@
  * Definitions of Secondary Processor-Based VM-Execution Controls.
  */
 #define SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES 0x00000001
+#define SECONDARY_EXEC_ENABLE_VPID              0x00000020
 #define SECONDARY_EXEC_WBINVD_EXITING           0x00000040
 
 
@@ -65,6 +66,7 @@
 
 /* VMCS Encodings */
 enum vmcs_field {
+        VIRTUAL_PROCESSOR_ID            = 0x00000000,
         GUEST_ES_SELECTOR               = 0x00000800,
         GUEST_CS_SELECTOR               = 0x00000802,
         GUEST_SS_SELECTOR               = 0x00000804,
@@ -321,4 +323,8 @@ enum vmcs_field {
 
 #define APIC_ACCESS_PAGE_PRIVATE_MEMSLOT        9
 
+#define VMX_NR_VPIDS                            (1 << 16)
+#define VMX_VPID_EXTENT_SINGLE_CONTEXT          1
+#define VMX_VPID_EXTENT_ALL_CONTEXT             2
+
 #endif
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index e076790ee794..28e8177ea4a0 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -601,6 +601,7 @@ static inline void kvm_inject_gp(struct kvm_vcpu *vcpu, u32 error_code)
 #define ASM_VMX_VMWRITE_RSP_RDX   ".byte 0x0f, 0x79, 0xd4"
 #define ASM_VMX_VMXOFF            ".byte 0x0f, 0x01, 0xc4"
 #define ASM_VMX_VMXON_RAX         ".byte 0xf3, 0x0f, 0xc7, 0x30"
+#define ASM_VMX_INVVPID           ".byte 0x66, 0x0f, 0x38, 0x81, 0x08"
 
 #define MSR_IA32_TIME_STAMP_COUNTER             0x010