Commit 904e14fb authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: VMX: make MSR bitmaps per-VCPU



Place the MSR bitmap in struct loaded_vmcs, and update it in place
every time the x2apic or APICv state can change.  This is rare and
the loop can handle 64 MSRs per iteration, in a similar fashion as
nested_vmx_prepare_msr_bitmap.

This prepares for choosing, on a per-VM basis, whether to intercept
the SPEC_CTRL and PRED_CMD MSRs.

Cc: stable@vger.kernel.org       # prereq for Spectre mitigation
Suggested-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f21f165e
......@@ -111,6 +111,14 @@ static u64 __read_mostly host_xss;
static bool __read_mostly enable_pml = 1;
module_param_named(pml, enable_pml, bool, S_IRUGO);
#define MSR_TYPE_R 1
#define MSR_TYPE_W 2
#define MSR_TYPE_RW 3
#define MSR_BITMAP_MODE_X2APIC 1
#define MSR_BITMAP_MODE_X2APIC_APICV 2
#define MSR_BITMAP_MODE_LM 4
#define KVM_VMX_TSC_MULTIPLIER_MAX 0xffffffffffffffffULL
/* Guest_tsc -> host_tsc conversion requires 64-bit division. */
......@@ -209,6 +217,7 @@ struct loaded_vmcs {
int soft_vnmi_blocked;
ktime_t entry_time;
s64 vnmi_blocked_time;
unsigned long *msr_bitmap;
struct list_head loaded_vmcss_on_cpu_link;
};
......@@ -449,8 +458,6 @@ struct nested_vmx {
bool pi_pending;
u16 posted_intr_nv;
unsigned long *msr_bitmap;
struct hrtimer preemption_timer;
bool preemption_timer_expired;
......@@ -573,6 +580,7 @@ struct vcpu_vmx {
struct kvm_vcpu vcpu;
unsigned long host_rsp;
u8 fail;
u8 msr_bitmap_mode;
u32 exit_intr_info;
u32 idt_vectoring_info;
ulong rflags;
......@@ -927,6 +935,7 @@ static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu);
static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked);
static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
u16 error_code);
static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
......@@ -946,12 +955,6 @@ static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);
enum {
VMX_IO_BITMAP_A,
VMX_IO_BITMAP_B,
VMX_MSR_BITMAP_LEGACY,
VMX_MSR_BITMAP_LONGMODE,
VMX_MSR_BITMAP_LEGACY_X2APIC_APICV,
VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV,
VMX_MSR_BITMAP_LEGACY_X2APIC,
VMX_MSR_BITMAP_LONGMODE_X2APIC,
VMX_VMREAD_BITMAP,
VMX_VMWRITE_BITMAP,
VMX_BITMAP_NR
......@@ -961,12 +964,6 @@ static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
#define vmx_io_bitmap_a (vmx_bitmap[VMX_IO_BITMAP_A])
#define vmx_io_bitmap_b (vmx_bitmap[VMX_IO_BITMAP_B])
#define vmx_msr_bitmap_legacy (vmx_bitmap[VMX_MSR_BITMAP_LEGACY])
#define vmx_msr_bitmap_longmode (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE])
#define vmx_msr_bitmap_legacy_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV])
#define vmx_msr_bitmap_longmode_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV])
#define vmx_msr_bitmap_legacy_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC])
#define vmx_msr_bitmap_longmode_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC])
#define vmx_vmread_bitmap (vmx_bitmap[VMX_VMREAD_BITMAP])
#define vmx_vmwrite_bitmap (vmx_bitmap[VMX_VMWRITE_BITMAP])
......@@ -2564,36 +2561,6 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
vmx->guest_msrs[from] = tmp;
}
static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
{
unsigned long *msr_bitmap;
if (is_guest_mode(vcpu))
msr_bitmap = to_vmx(vcpu)->nested.msr_bitmap;
else if (cpu_has_secondary_exec_ctrls() &&
(vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
if (enable_apicv && kvm_vcpu_apicv_active(vcpu)) {
if (is_long_mode(vcpu))
msr_bitmap = vmx_msr_bitmap_longmode_x2apic_apicv;
else
msr_bitmap = vmx_msr_bitmap_legacy_x2apic_apicv;
} else {
if (is_long_mode(vcpu))
msr_bitmap = vmx_msr_bitmap_longmode_x2apic;
else
msr_bitmap = vmx_msr_bitmap_legacy_x2apic;
}
} else {
if (is_long_mode(vcpu))
msr_bitmap = vmx_msr_bitmap_longmode;
else
msr_bitmap = vmx_msr_bitmap_legacy;
}
vmcs_write64(MSR_BITMAP, __pa(msr_bitmap));
}
/*
* Set up the vmcs to automatically save and restore system
* msrs. Don't touch the 64-bit msrs if the guest is in legacy
......@@ -2634,7 +2601,7 @@ static void setup_msrs(struct vcpu_vmx *vmx)
vmx->save_nmsrs = save_nmsrs;
if (cpu_has_vmx_msr_bitmap())
vmx_set_msr_bitmap(&vmx->vcpu);
vmx_update_msr_bitmap(&vmx->vcpu);
}
/*
......@@ -3844,6 +3811,8 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
loaded_vmcs_clear(loaded_vmcs);
free_vmcs(loaded_vmcs->vmcs);
loaded_vmcs->vmcs = NULL;
if (loaded_vmcs->msr_bitmap)
free_page((unsigned long)loaded_vmcs->msr_bitmap);
WARN_ON(loaded_vmcs->shadow_vmcs != NULL);
}
......@@ -3860,7 +3829,18 @@ static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
loaded_vmcs->shadow_vmcs = NULL;
loaded_vmcs_init(loaded_vmcs);
if (cpu_has_vmx_msr_bitmap()) {
loaded_vmcs->msr_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
if (!loaded_vmcs->msr_bitmap)
goto out_vmcs;
memset(loaded_vmcs->msr_bitmap, 0xff, PAGE_SIZE);
}
return 0;
out_vmcs:
free_loaded_vmcs(loaded_vmcs);
return -ENOMEM;
}
static void free_kvm_area(void)
......@@ -4921,10 +4901,8 @@ static void free_vpid(int vpid)
spin_unlock(&vmx_vpid_lock);
}
#define MSR_TYPE_R 1
#define MSR_TYPE_W 2
static void __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
u32 msr, int type)
static void __always_inline vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
u32 msr, int type)
{
int f = sizeof(unsigned long);
......@@ -4958,6 +4936,50 @@ static void __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
}
}
static void __always_inline vmx_enable_intercept_for_msr(unsigned long *msr_bitmap,
u32 msr, int type)
{
int f = sizeof(unsigned long);
if (!cpu_has_vmx_msr_bitmap())
return;
/*
* See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address). Early manuals
* have the write-low and read-high bitmap offsets the wrong way round.
* We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.
*/
if (msr <= 0x1fff) {
if (type & MSR_TYPE_R)
/* read-low */
__set_bit(msr, msr_bitmap + 0x000 / f);
if (type & MSR_TYPE_W)
/* write-low */
__set_bit(msr, msr_bitmap + 0x800 / f);
} else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
msr &= 0x1fff;
if (type & MSR_TYPE_R)
/* read-high */
__set_bit(msr, msr_bitmap + 0x400 / f);
if (type & MSR_TYPE_W)
/* write-high */
__set_bit(msr, msr_bitmap + 0xc00 / f);
}
}
static void __always_inline vmx_set_intercept_for_msr(unsigned long *msr_bitmap,
u32 msr, int type, bool value)
{
if (value)
vmx_enable_intercept_for_msr(msr_bitmap, msr, type);
else
vmx_disable_intercept_for_msr(msr_bitmap, msr, type);
}
/*
* If a msr is allowed by L0, we should check whether it is allowed by L1.
* The corresponding bit will be cleared unless both of L0 and L1 allow it.
......@@ -5004,30 +5026,70 @@ static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1,
}
}
static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
static u8 vmx_msr_bitmap_mode(struct kvm_vcpu *vcpu)
{
if (!longmode_only)
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy,
msr, MSR_TYPE_R | MSR_TYPE_W);
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode,
msr, MSR_TYPE_R | MSR_TYPE_W);
u8 mode = 0;
if (cpu_has_secondary_exec_ctrls() &&
(vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
mode |= MSR_BITMAP_MODE_X2APIC;
if (enable_apicv && kvm_vcpu_apicv_active(vcpu))
mode |= MSR_BITMAP_MODE_X2APIC_APICV;
}
if (is_long_mode(vcpu))
mode |= MSR_BITMAP_MODE_LM;
return mode;
}
static void vmx_disable_intercept_msr_x2apic(u32 msr, int type, bool apicv_active)
#define X2APIC_MSR(r) (APIC_BASE_MSR + ((r) >> 4))
static void vmx_update_msr_bitmap_x2apic(unsigned long *msr_bitmap,
u8 mode)
{
if (apicv_active) {
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic_apicv,
msr, type);
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic_apicv,
msr, type);
} else {
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic,
msr, type);
__vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic,
msr, type);
int msr;
for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
unsigned word = msr / BITS_PER_LONG;
msr_bitmap[word] = (mode & MSR_BITMAP_MODE_X2APIC_APICV) ? 0 : ~0;
msr_bitmap[word + (0x800 / sizeof(long))] = ~0;
}
if (mode & MSR_BITMAP_MODE_X2APIC) {
/*
* TPR reads and writes can be virtualized even if virtual interrupt
* delivery is not in use.
*/
vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_TASKPRI), MSR_TYPE_RW);
if (mode & MSR_BITMAP_MODE_X2APIC_APICV) {
vmx_enable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_TMCCT), MSR_TYPE_R);
vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_EOI), MSR_TYPE_W);
vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_SELF_IPI), MSR_TYPE_W);
}
}
}
static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
u8 mode = vmx_msr_bitmap_mode(vcpu);
u8 changed = mode ^ vmx->msr_bitmap_mode;
if (!changed)
return;
vmx_set_intercept_for_msr(msr_bitmap, MSR_KERNEL_GS_BASE, MSR_TYPE_RW,
!(mode & MSR_BITMAP_MODE_LM));
if (changed & (MSR_BITMAP_MODE_X2APIC | MSR_BITMAP_MODE_X2APIC_APICV))
vmx_update_msr_bitmap_x2apic(msr_bitmap, mode);
vmx->msr_bitmap_mode = mode;
}
static bool vmx_get_enable_apicv(struct kvm_vcpu *vcpu)
{
return enable_apicv;
......@@ -5277,7 +5339,7 @@ static void vmx_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
}
if (cpu_has_vmx_msr_bitmap())
vmx_set_msr_bitmap(vcpu);
vmx_update_msr_bitmap(vcpu);
}
static u32 vmx_exec_control(struct vcpu_vmx *vmx)
......@@ -5464,7 +5526,7 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap));
}
if (cpu_has_vmx_msr_bitmap())
vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap_legacy));
vmcs_write64(MSR_BITMAP, __pa(vmx->vmcs01.msr_bitmap));
vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */
......@@ -6747,7 +6809,7 @@ void vmx_enable_tdp(void)
static __init int hardware_setup(void)
{
int r = -ENOMEM, i, msr;
int r = -ENOMEM, i;
rdmsrl_safe(MSR_EFER, &host_efer);
......@@ -6767,9 +6829,6 @@ static __init int hardware_setup(void)
memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE);
memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
if (setup_vmcs_config(&vmcs_config) < 0) {
r = -EIO;
goto out;
......@@ -6838,42 +6897,8 @@ static __init int hardware_setup(void)
kvm_tsc_scaling_ratio_frac_bits = 48;
}
vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
memcpy(vmx_msr_bitmap_legacy_x2apic_apicv,
vmx_msr_bitmap_legacy, PAGE_SIZE);
memcpy(vmx_msr_bitmap_longmode_x2apic_apicv,
vmx_msr_bitmap_longmode, PAGE_SIZE);
memcpy(vmx_msr_bitmap_legacy_x2apic,
vmx_msr_bitmap_legacy, PAGE_SIZE);
memcpy(vmx_msr_bitmap_longmode_x2apic,
vmx_msr_bitmap_longmode, PAGE_SIZE);
set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
for (msr = 0x800; msr <= 0x8ff; msr++) {
if (msr == 0x839 /* TMCCT */)
continue;
vmx_disable_intercept_msr_x2apic(msr, MSR_TYPE_R, true);
}
/*
* TPR reads and writes can be virtualized even if virtual interrupt
* delivery is not in use.
*/
vmx_disable_intercept_msr_x2apic(0x808, MSR_TYPE_W, true);
vmx_disable_intercept_msr_x2apic(0x808, MSR_TYPE_R | MSR_TYPE_W, false);
/* EOI */
vmx_disable_intercept_msr_x2apic(0x80b, MSR_TYPE_W, true);
/* SELF-IPI */
vmx_disable_intercept_msr_x2apic(0x83f, MSR_TYPE_W, true);
if (enable_ept)
vmx_enable_tdp();
else
......@@ -7162,13 +7187,6 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
if (r < 0)
goto out_vmcs02;
if (cpu_has_vmx_msr_bitmap()) {
vmx->nested.msr_bitmap =
(unsigned long *)__get_free_page(GFP_KERNEL);
if (!vmx->nested.msr_bitmap)
goto out_msr_bitmap;
}
vmx->nested.cached_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL);
if (!vmx->nested.cached_vmcs12)
goto out_cached_vmcs12;
......@@ -7195,9 +7213,6 @@ out_shadow_vmcs:
kfree(vmx->nested.cached_vmcs12);
out_cached_vmcs12:
free_page((unsigned long)vmx->nested.msr_bitmap);
out_msr_bitmap:
free_loaded_vmcs(&vmx->nested.vmcs02);
out_vmcs02:
......@@ -7343,10 +7358,6 @@ static void free_nested(struct vcpu_vmx *vmx)
free_vpid(vmx->nested.vpid02);
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
if (vmx->nested.msr_bitmap) {
free_page((unsigned long)vmx->nested.msr_bitmap);
vmx->nested.msr_bitmap = NULL;
}
if (enable_shadow_vmcs) {
vmx_disable_shadow_vmcs(vmx);
vmcs_clear(vmx->vmcs01.shadow_vmcs);
......@@ -8862,7 +8873,7 @@ static void vmx_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
}
vmcs_write32(SECONDARY_VM_EXEC_CONTROL, sec_exec_control);
vmx_set_msr_bitmap(vcpu);
vmx_update_msr_bitmap(vcpu);
}
static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu, hpa_t hpa)
......@@ -9523,6 +9534,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
{
int err;
struct vcpu_vmx *vmx = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
unsigned long *msr_bitmap;
int cpu;
if (!vmx)
......@@ -9559,6 +9571,15 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
if (err < 0)
goto free_msrs;
msr_bitmap = vmx->vmcs01.msr_bitmap;
vmx_disable_intercept_for_msr(msr_bitmap, MSR_FS_BASE, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_GS_BASE, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_KERNEL_GS_BASE, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_CS, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_ESP, MSR_TYPE_RW);
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_EIP, MSR_TYPE_RW);
vmx->msr_bitmap_mode = 0;
vmx->loaded_vmcs = &vmx->vmcs01;
cpu = get_cpu();
vmx_vcpu_load(&vmx->vcpu, cpu);
......@@ -10022,7 +10043,7 @@ static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
int msr;
struct page *page;
unsigned long *msr_bitmap_l1;
unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.msr_bitmap;
unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.vmcs02.msr_bitmap;
/* This shortcut is ok because we support only x2APIC MSRs so far. */
if (!nested_cpu_has_virt_x2apic_mode(vmcs12))
......@@ -10599,6 +10620,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
if (kvm_has_tsc_control)
decache_tsc_multiplier(vmx);
if (cpu_has_vmx_msr_bitmap())
vmcs_write64(MSR_BITMAP, __pa(vmx->nested.vmcs02.msr_bitmap));
if (enable_vpid) {
/*
* There is no direct mapping between vpid02 and vpid12, the
......@@ -11397,7 +11421,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
if (cpu_has_vmx_msr_bitmap())
vmx_set_msr_bitmap(vcpu);
vmx_update_msr_bitmap(vcpu);
if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
vmcs12->vm_exit_msr_load_count))
......
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