[PATCH 13/40] KVM: VMX: Enable Virtual Processor Identification (VPID)

[Avi Kivity]

From: Sheng Yang <sheng.yang@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
 arch/x86/kvm/vmx.c         |   80 +++++++++++++++++++++++++++++++++++++++++---
 arch/x86/kvm/vmx.h         |    6 +++
 include/asm-x86/kvm_host.h |    1 +
 3 files changed, 82 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8e14628..1157e8a 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 d52ae8d..436ce0f 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 d6db0de..67ae307 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -600,6 +600,7 @@ 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
 
-- 
1.5.4.5

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