KVM: x86: Introduce KVM_GET_SREGS2 / KVM_SET_SREGS2

This is a new version of KVM_GET_SREGS / KVM_SET_SREGS.

It has the following changes:
   * Has flags for future extensions
   * Has vcpu's PDPTRs, allowing to save/restore them on migration.
   * Lacks obsolete interrupt bitmap (done now via KVM_SET_VCPU_EVENTS)

New capability, KVM_CAP_SREGS2 is added to signal
the userspace of this ioctl.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210607090203.133058-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2021-06-07 12:02:02 +03:00 committed by Paolo Bonzini
parent 329675dde9
commit 6dba940352
5 changed files with 185 additions and 27 deletions

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@ -5034,6 +5034,54 @@ see KVM_XEN_VCPU_SET_ATTR above.
The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used
with the KVM_XEN_VCPU_GET_ATTR ioctl.
4.131 KVM_GET_SREGS2
------------------
:Capability: KVM_CAP_SREGS2
:Architectures: x86
:Type: vcpu ioctl
:Parameters: struct kvm_sregs2 (out)
:Returns: 0 on success, -1 on error
Reads special registers from the vcpu.
This ioctl (when supported) replaces the KVM_GET_SREGS.
::
struct kvm_sregs2 {
/* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */
struct kvm_segment cs, ds, es, fs, gs, ss;
struct kvm_segment tr, ldt;
struct kvm_dtable gdt, idt;
__u64 cr0, cr2, cr3, cr4, cr8;
__u64 efer;
__u64 apic_base;
__u64 flags;
__u64 pdptrs[4];
};
flags values for ``kvm_sregs2``:
``KVM_SREGS2_FLAGS_PDPTRS_VALID``
Indicates thats the struct contain valid PDPTR values.
4.132 KVM_SET_SREGS2
------------------
:Capability: KVM_CAP_SREGS2
:Architectures: x86
:Type: vcpu ioctl
:Parameters: struct kvm_sregs2 (in)
:Returns: 0 on success, -1 on error
Writes special registers into the vcpu.
See KVM_GET_SREGS2 for the data structures.
This ioctl (when supported) replaces the KVM_SET_SREGS.
5. The kvm_run structure
========================

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@ -159,6 +159,19 @@ struct kvm_sregs {
__u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64];
};
struct kvm_sregs2 {
/* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */
struct kvm_segment cs, ds, es, fs, gs, ss;
struct kvm_segment tr, ldt;
struct kvm_dtable gdt, idt;
__u64 cr0, cr2, cr3, cr4, cr8;
__u64 efer;
__u64 apic_base;
__u64 flags;
__u64 pdptrs[4];
};
#define KVM_SREGS2_FLAGS_PDPTRS_VALID 1
/* for KVM_GET_FPU and KVM_SET_FPU */
struct kvm_fpu {
__u8 fpr[8][16];

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@ -125,6 +125,11 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
return vcpu->arch.walk_mmu->pdptrs[index];
}
static inline void kvm_pdptr_write(struct kvm_vcpu *vcpu, int index, u64 value)
{
vcpu->arch.walk_mmu->pdptrs[index] = value;
}
static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)
{
ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS;

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@ -114,6 +114,9 @@ static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
static void store_regs(struct kvm_vcpu *vcpu);
static int sync_regs(struct kvm_vcpu *vcpu);
static int __set_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2);
static void __get_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2);
struct kvm_x86_ops kvm_x86_ops __read_mostly;
EXPORT_SYMBOL_GPL(kvm_x86_ops);
@ -817,7 +820,6 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
memcpy(mmu->pdptrs, pdpte, sizeof(mmu->pdptrs));
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
out:
return ret;
@ -3956,6 +3958,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_SGX_ATTRIBUTE:
#endif
case KVM_CAP_VM_COPY_ENC_CONTEXT_FROM:
case KVM_CAP_SREGS2:
r = 1;
break;
case KVM_CAP_SET_GUEST_DEBUG2:
@ -4870,6 +4873,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
void __user *argp = (void __user *)arg;
int r;
union {
struct kvm_sregs2 *sregs2;
struct kvm_lapic_state *lapic;
struct kvm_xsave *xsave;
struct kvm_xcrs *xcrs;
@ -5242,6 +5246,28 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
break;
}
#endif
case KVM_GET_SREGS2: {
u.sregs2 = kzalloc(sizeof(struct kvm_sregs2), GFP_KERNEL);
r = -ENOMEM;
if (!u.sregs2)
goto out;
__get_sregs2(vcpu, u.sregs2);
r = -EFAULT;
if (copy_to_user(argp, u.sregs2, sizeof(struct kvm_sregs2)))
goto out;
r = 0;
break;
}
case KVM_SET_SREGS2: {
u.sregs2 = memdup_user(argp, sizeof(struct kvm_sregs2));
if (IS_ERR(u.sregs2)) {
r = PTR_ERR(u.sregs2);
u.sregs2 = NULL;
goto out;
}
r = __set_sregs2(vcpu, u.sregs2);
break;
}
default:
r = -EINVAL;
}
@ -9937,7 +9963,7 @@ void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
}
EXPORT_SYMBOL_GPL(kvm_get_cs_db_l_bits);
static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
static void __get_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
{
struct desc_ptr dt;
@ -9970,14 +9996,36 @@ skip_protected_regs:
sregs->cr8 = kvm_get_cr8(vcpu);
sregs->efer = vcpu->arch.efer;
sregs->apic_base = kvm_get_apic_base(vcpu);
}
memset(sregs->interrupt_bitmap, 0, sizeof(sregs->interrupt_bitmap));
static void __get_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
{
__get_sregs_common(vcpu, sregs);
if (vcpu->arch.guest_state_protected)
return;
if (vcpu->arch.interrupt.injected && !vcpu->arch.interrupt.soft)
set_bit(vcpu->arch.interrupt.nr,
(unsigned long *)sregs->interrupt_bitmap);
}
static void __get_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2)
{
int i;
__get_sregs_common(vcpu, (struct kvm_sregs *)sregs2);
if (vcpu->arch.guest_state_protected)
return;
if (is_pae_paging(vcpu)) {
for (i = 0 ; i < 4 ; i++)
sregs2->pdptrs[i] = kvm_pdptr_read(vcpu, i);
sregs2->flags |= KVM_SREGS2_FLAGS_PDPTRS_VALID;
}
}
int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
struct kvm_sregs *sregs)
{
@ -10096,24 +10144,23 @@ static bool kvm_is_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
return kvm_is_valid_cr4(vcpu, sregs->cr4);
}
static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs,
int *mmu_reset_needed, bool update_pdptrs)
{
struct msr_data apic_base_msr;
int mmu_reset_needed = 0;
int pending_vec, max_bits, idx;
int idx;
struct desc_ptr dt;
int ret = -EINVAL;
if (!kvm_is_valid_sregs(vcpu, sregs))
goto out;
return -EINVAL;
apic_base_msr.data = sregs->apic_base;
apic_base_msr.host_initiated = true;
if (kvm_set_apic_base(vcpu, &apic_base_msr))
goto out;
return -EINVAL;
if (vcpu->arch.guest_state_protected)
goto skip_protected_regs;
return 0;
dt.size = sregs->idt.limit;
dt.address = sregs->idt.base;
@ -10123,31 +10170,30 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
static_call(kvm_x86_set_gdt)(vcpu, &dt);
vcpu->arch.cr2 = sregs->cr2;
mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;
*mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;
vcpu->arch.cr3 = sregs->cr3;
kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
kvm_set_cr8(vcpu, sregs->cr8);
mmu_reset_needed |= vcpu->arch.efer != sregs->efer;
*mmu_reset_needed |= vcpu->arch.efer != sregs->efer;
static_call(kvm_x86_set_efer)(vcpu, sregs->efer);
mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0;
*mmu_reset_needed |= kvm_read_cr0(vcpu) != sregs->cr0;
static_call(kvm_x86_set_cr0)(vcpu, sregs->cr0);
vcpu->arch.cr0 = sregs->cr0;
mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4;
*mmu_reset_needed |= kvm_read_cr4(vcpu) != sregs->cr4;
static_call(kvm_x86_set_cr4)(vcpu, sregs->cr4);
idx = srcu_read_lock(&vcpu->kvm->srcu);
if (is_pae_paging(vcpu)) {
load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
mmu_reset_needed = 1;
if (update_pdptrs) {
idx = srcu_read_lock(&vcpu->kvm->srcu);
if (is_pae_paging(vcpu)) {
load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
*mmu_reset_needed = 1;
}
srcu_read_unlock(&vcpu->kvm->srcu, idx);
}
srcu_read_unlock(&vcpu->kvm->srcu, idx);
if (mmu_reset_needed)
kvm_mmu_reset_context(vcpu);
kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
kvm_set_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
@ -10167,20 +10213,62 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
!is_protmode(vcpu))
vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
skip_protected_regs:
return 0;
}
static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
{
int pending_vec, max_bits;
int mmu_reset_needed = 0;
int ret = __set_sregs_common(vcpu, sregs, &mmu_reset_needed, true);
if (ret)
return ret;
if (mmu_reset_needed)
kvm_mmu_reset_context(vcpu);
max_bits = KVM_NR_INTERRUPTS;
pending_vec = find_first_bit(
(const unsigned long *)sregs->interrupt_bitmap, max_bits);
if (pending_vec < max_bits) {
kvm_queue_interrupt(vcpu, pending_vec, false);
pr_debug("Set back pending irq %d\n", pending_vec);
kvm_make_request(KVM_REQ_EVENT, vcpu);
}
return 0;
}
kvm_make_request(KVM_REQ_EVENT, vcpu);
static int __set_sregs2(struct kvm_vcpu *vcpu, struct kvm_sregs2 *sregs2)
{
int mmu_reset_needed = 0;
bool valid_pdptrs = sregs2->flags & KVM_SREGS2_FLAGS_PDPTRS_VALID;
bool pae = (sregs2->cr0 & X86_CR0_PG) && (sregs2->cr4 & X86_CR4_PAE) &&
!(sregs2->efer & EFER_LMA);
int i, ret;
ret = 0;
out:
return ret;
if (sregs2->flags & ~KVM_SREGS2_FLAGS_PDPTRS_VALID)
return -EINVAL;
if (valid_pdptrs && (!pae || vcpu->arch.guest_state_protected))
return -EINVAL;
ret = __set_sregs_common(vcpu, (struct kvm_sregs *)sregs2,
&mmu_reset_needed, !valid_pdptrs);
if (ret)
return ret;
if (valid_pdptrs) {
for (i = 0; i < 4 ; i++)
kvm_pdptr_write(vcpu, i, sregs2->pdptrs[i]);
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
mmu_reset_needed = 1;
}
if (mmu_reset_needed)
kvm_mmu_reset_context(vcpu);
return 0;
}
int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,

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@ -1084,6 +1084,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 197
#define KVM_CAP_PTP_KVM 198
#define KVM_CAP_HYPERV_ENFORCE_CPUID 199
#define KVM_CAP_SREGS2 200
#ifdef KVM_CAP_IRQ_ROUTING
@ -1622,6 +1623,9 @@ struct kvm_xen_hvm_attr {
#define KVM_XEN_VCPU_GET_ATTR _IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr)
#define KVM_XEN_VCPU_SET_ATTR _IOW(KVMIO, 0xcb, struct kvm_xen_vcpu_attr)
#define KVM_GET_SREGS2 _IOR(KVMIO, 0xcc, struct kvm_sregs2)
#define KVM_SET_SREGS2 _IOW(KVMIO, 0xcd, struct kvm_sregs2)
struct kvm_xen_vcpu_attr {
__u16 type;
__u16 pad[3];