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KVM: VMX: Enable Virtual Processor Identification (VPID)
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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>
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Sheng Yang authored and Avi Kivity committed Apr 27, 2008
1 parent adb1ff4 commit 2384d2b
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Showing 3 changed files with 82 additions and 5 deletions.
80 changes: 75 additions & 5 deletions arch/x86/kvm/vmx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -71,6 +74,7 @@ struct vcpu_vmx {
unsigned rip;
} irq;
} rmode;
int vpid;
};

static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -1494,6 +1537,22 @@ static int alloc_apic_access_page(struct kvm *kvm)
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.
*/
Expand Down Expand Up @@ -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);
}

Expand Down Expand Up @@ -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);
Expand All @@ -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:
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down
6 changes: 6 additions & 0 deletions arch/x86/kvm/vmx.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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


Expand All @@ -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,
Expand Down Expand Up @@ -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
1 change: 1 addition & 0 deletions include/asm-x86/kvm_host.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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

Expand Down

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