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alistair23-linux/arch/x86/kvm/x86.h
Sean Christopherson 361209e054 KVM: Explicitly define the "memslot update in-progress" bit 
KVM uses bit 0 of the memslots generation as an "update in-progress"
flag, which is used by x86 to prevent caching MMIO access while the
memslots are changing.  Although the intended behavior is flag-like,
e.g. MMIO sptes intentionally drop the in-progress bit so as to avoid
caching data from in-flux memslots, the implementation oftentimes treats
the bit as part of the generation number itself, e.g. incrementing the
generation increments twice, once to set the flag and once to clear it.

Prior to commit 4bd518f159 ("KVM: use separate generations for
each address space"), incorporating the "update in-progress" bit into
the generation number largely made sense, e.g. "real" generations are
even, "bogus" generations are odd, most code doesn't need to be aware of
the bit, etc...

Now that unique memslots generation numbers are assigned to each address
space, stealthing the in-progress status into the generation number
results in a wide variety of subtle code, e.g. kvm_create_vm() jumps
over bit 0 when initializing the memslots generation without any hint as
to why.

Explicitly define the flag and convert as much code as possible (which
isn't much) to actually treat it like a flag.  This paves the way for
eventually using a different bit for "update in-progress" so that it can
be a flag in truth instead of a awkward extension to the generation
number.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20 22:48:34 +01:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef ARCH_X86_KVM_X86_H
#define ARCH_X86_KVM_X86_H
#include <linux/kvm_host.h>
#include <asm/pvclock.h>
#include "kvm_cache_regs.h"
#define KVM_DEFAULT_PLE_GAP 128
#define KVM_VMX_DEFAULT_PLE_WINDOW 4096
#define KVM_DEFAULT_PLE_WINDOW_GROW 2
#define KVM_DEFAULT_PLE_WINDOW_SHRINK 0
#define KVM_VMX_DEFAULT_PLE_WINDOW_MAX UINT_MAX
#define KVM_SVM_DEFAULT_PLE_WINDOW_MAX USHRT_MAX
#define KVM_SVM_DEFAULT_PLE_WINDOW 3000
static inline unsigned int __grow_ple_window(unsigned int val,
unsigned int base, unsigned int modifier, unsigned int max)
{
u64 ret = val;
if (modifier < 1)
return base;
if (modifier < base)
ret *= modifier;
else
ret += modifier;
return min(ret, (u64)max);
}
static inline unsigned int __shrink_ple_window(unsigned int val,
unsigned int base, unsigned int modifier, unsigned int min)
{
if (modifier < 1)
return base;
if (modifier < base)
val /= modifier;
else
val -= modifier;
return max(val, min);
}
#define MSR_IA32_CR_PAT_DEFAULT 0x0007040600070406ULL
static inline void kvm_clear_exception_queue(struct kvm_vcpu *vcpu)
{
vcpu->arch.exception.pending = false;
vcpu->arch.exception.injected = false;
}
static inline void kvm_queue_interrupt(struct kvm_vcpu *vcpu, u8 vector,
bool soft)
{
vcpu->arch.interrupt.injected = true;
vcpu->arch.interrupt.soft = soft;
vcpu->arch.interrupt.nr = vector;
}
static inline void kvm_clear_interrupt_queue(struct kvm_vcpu *vcpu)
{
vcpu->arch.interrupt.injected = false;
}
static inline bool kvm_event_needs_reinjection(struct kvm_vcpu *vcpu)
{
return vcpu->arch.exception.injected || vcpu->arch.interrupt.injected ||
vcpu->arch.nmi_injected;
}
static inline bool kvm_exception_is_soft(unsigned int nr)
{
return (nr == BP_VECTOR) || (nr == OF_VECTOR);
}
static inline bool is_protmode(struct kvm_vcpu *vcpu)
{
return kvm_read_cr0_bits(vcpu, X86_CR0_PE);
}
static inline int is_long_mode(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
return vcpu->arch.efer & EFER_LMA;
#else
return 0;
#endif
}
static inline bool is_64_bit_mode(struct kvm_vcpu *vcpu)
{
int cs_db, cs_l;
if (!is_long_mode(vcpu))
return false;
kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
return cs_l;
}
static inline bool is_la57_mode(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
return (vcpu->arch.efer & EFER_LMA) &&
kvm_read_cr4_bits(vcpu, X86_CR4_LA57);
#else
return 0;
#endif
}
static inline bool x86_exception_has_error_code(unsigned int vector)
{
static u32 exception_has_error_code = BIT(DF_VECTOR) | BIT(TS_VECTOR) |
BIT(NP_VECTOR) | BIT(SS_VECTOR) | BIT(GP_VECTOR) |
BIT(PF_VECTOR) | BIT(AC_VECTOR);
return (1U << vector) & exception_has_error_code;
}
static inline bool mmu_is_nested(struct kvm_vcpu *vcpu)
{
return vcpu->arch.walk_mmu == &vcpu->arch.nested_mmu;
}
static inline int is_pae(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, X86_CR4_PAE);
}
static inline int is_pse(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, X86_CR4_PSE);
}
static inline int is_paging(struct kvm_vcpu *vcpu)
{
return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
}
static inline u32 bit(int bitno)
{
return 1 << (bitno & 31);
}
static inline u8 vcpu_virt_addr_bits(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, X86_CR4_LA57) ? 57 : 48;
}
static inline u8 ctxt_virt_addr_bits(struct x86_emulate_ctxt *ctxt)
{
return (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_LA57) ? 57 : 48;
}
static inline u64 get_canonical(u64 la, u8 vaddr_bits)
{
return ((int64_t)la << (64 - vaddr_bits)) >> (64 - vaddr_bits);
}
static inline bool is_noncanonical_address(u64 la, struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
return get_canonical(la, vcpu_virt_addr_bits(vcpu)) != la;
#else
return false;
#endif
}
static inline bool emul_is_noncanonical_address(u64 la,
struct x86_emulate_ctxt *ctxt)
{
#ifdef CONFIG_X86_64
return get_canonical(la, ctxt_virt_addr_bits(ctxt)) != la;
#else
return false;
#endif
}
static inline void vcpu_cache_mmio_info(struct kvm_vcpu *vcpu,
gva_t gva, gfn_t gfn, unsigned access)
{
u64 gen = kvm_memslots(vcpu->kvm)->generation;
if (unlikely(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS))
return;
/*
* If this is a shadow nested page table, the "GVA" is
* actually a nGPA.
*/
vcpu->arch.mmio_gva = mmu_is_nested(vcpu) ? 0 : gva & PAGE_MASK;
vcpu->arch.access = access;
vcpu->arch.mmio_gfn = gfn;
vcpu->arch.mmio_gen = gen;
}
static inline bool vcpu_match_mmio_gen(struct kvm_vcpu *vcpu)
{
return vcpu->arch.mmio_gen == kvm_memslots(vcpu->kvm)->generation;
}
/*
* Clear the mmio cache info for the given gva. If gva is MMIO_GVA_ANY, we
* clear all mmio cache info.
*/
#define MMIO_GVA_ANY (~(gva_t)0)
static inline void vcpu_clear_mmio_info(struct kvm_vcpu *vcpu, gva_t gva)
{
if (gva != MMIO_GVA_ANY && vcpu->arch.mmio_gva != (gva & PAGE_MASK))
return;
vcpu->arch.mmio_gva = 0;
}
static inline bool vcpu_match_mmio_gva(struct kvm_vcpu *vcpu, unsigned long gva)
{
if (vcpu_match_mmio_gen(vcpu) && vcpu->arch.mmio_gva &&
vcpu->arch.mmio_gva == (gva & PAGE_MASK))
return true;
return false;
}
static inline bool vcpu_match_mmio_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)
{
if (vcpu_match_mmio_gen(vcpu) && vcpu->arch.mmio_gfn &&
vcpu->arch.mmio_gfn == gpa >> PAGE_SHIFT)
return true;
return false;
}
static inline unsigned long kvm_register_readl(struct kvm_vcpu *vcpu,
enum kvm_reg reg)
{
unsigned long val = kvm_register_read(vcpu, reg);
return is_64_bit_mode(vcpu) ? val : (u32)val;
}
static inline void kvm_register_writel(struct kvm_vcpu *vcpu,
enum kvm_reg reg,
unsigned long val)
{
if (!is_64_bit_mode(vcpu))
val = (u32)val;
return kvm_register_write(vcpu, reg, val);
}
static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
{
return !(kvm->arch.disabled_quirks & quirk);
}
void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr);
u64 get_kvmclock_ns(struct kvm *kvm);
int kvm_read_guest_virt(struct kvm_vcpu *vcpu,
gva_t addr, void *val, unsigned int bytes,
struct x86_exception *exception);
int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu,
gva_t addr, void *val, unsigned int bytes,
struct x86_exception *exception);
int handle_ud(struct kvm_vcpu *vcpu);
void kvm_deliver_exception_payload(struct kvm_vcpu *vcpu);
void kvm_vcpu_mtrr_init(struct kvm_vcpu *vcpu);
u8 kvm_mtrr_get_guest_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn);
bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data);
int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data);
int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,
int page_num);
bool kvm_vector_hashing_enabled(void);
int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
int emulation_type, void *insn, int insn_len);
#define KVM_SUPPORTED_XCR0 (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
| XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
| XFEATURE_MASK_PKRU)
extern u64 host_xcr0;
extern u64 kvm_supported_xcr0(void);
extern unsigned int min_timer_period_us;
extern unsigned int lapic_timer_advance_ns;
extern bool enable_vmware_backdoor;
extern struct static_key kvm_no_apic_vcpu;
static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
{
return pvclock_scale_delta(nsec, vcpu->arch.virtual_tsc_mult,
vcpu->arch.virtual_tsc_shift);
}
/* Same "calling convention" as do_div:
* - divide (n << 32) by base
* - put result in n
* - return remainder
*/
#define do_shl32_div32(n, base) \
({ \
u32 __quot, __rem; \
asm("divl %2" : "=a" (__quot), "=d" (__rem) \
: "rm" (base), "0" (0), "1" ((u32) n)); \
n = __quot; \
__rem; \
})
static inline bool kvm_mwait_in_guest(struct kvm *kvm)
{
return kvm->arch.mwait_in_guest;
}
static inline bool kvm_hlt_in_guest(struct kvm *kvm)
{
return kvm->arch.hlt_in_guest;
}
static inline bool kvm_pause_in_guest(struct kvm *kvm)
{
return kvm->arch.pause_in_guest;
}
DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);
static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu)
{
__this_cpu_write(current_vcpu, vcpu);
}
static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
{
__this_cpu_write(current_vcpu, NULL);
}
#endif
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