xref: /linux/arch/x86/kvm/mmu.h (revision 97ec8c067d322d32effdc1701760d3babbc5595f)

#ifndef __KVM_X86_MMU_H
#define __KVM_X86_MMU_H

#include <linux/kvm_host.h>
#include "kvm_cache_regs.h"

#define PT64_PT_BITS 9
#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
#define PT32_PT_BITS 10
#define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)

#define PT_WRITABLE_SHIFT 1

#define PT_PRESENT_MASK (1ULL << 0)
#define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
#define PT_USER_MASK (1ULL << 2)
#define PT_PWT_MASK (1ULL << 3)
#define PT_PCD_MASK (1ULL << 4)
#define PT_ACCESSED_SHIFT 5
#define PT_ACCESSED_MASK (1ULL << PT_ACCESSED_SHIFT)
#define PT_DIRTY_SHIFT 6
#define PT_DIRTY_MASK (1ULL << PT_DIRTY_SHIFT)
#define PT_PAGE_SIZE_SHIFT 7
#define PT_PAGE_SIZE_MASK (1ULL << PT_PAGE_SIZE_SHIFT)
#define PT_PAT_MASK (1ULL << 7)
#define PT_GLOBAL_MASK (1ULL << 8)
#define PT64_NX_SHIFT 63
#define PT64_NX_MASK (1ULL << PT64_NX_SHIFT)

#define PT_PAT_SHIFT 7
#define PT_DIR_PAT_SHIFT 12
#define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)

#define PT32_DIR_PSE36_SIZE 4
#define PT32_DIR_PSE36_SHIFT 13
#define PT32_DIR_PSE36_MASK \
	(((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)

#define PT64_ROOT_LEVEL 4
#define PT32_ROOT_LEVEL 2
#define PT32E_ROOT_LEVEL 3

#define PT_PDPE_LEVEL 3
#define PT_DIRECTORY_LEVEL 2
#define PT_PAGE_TABLE_LEVEL 1

#define PFERR_PRESENT_BIT 0
#define PFERR_WRITE_BIT 1
#define PFERR_USER_BIT 2
#define PFERR_RSVD_BIT 3
#define PFERR_FETCH_BIT 4

#define PFERR_PRESENT_MASK (1U << PFERR_PRESENT_BIT)
#define PFERR_WRITE_MASK (1U << PFERR_WRITE_BIT)
#define PFERR_USER_MASK (1U << PFERR_USER_BIT)
#define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT)
#define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT)

int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4]);
void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask);

/*
 * Return values of handle_mmio_page_fault_common:
 * RET_MMIO_PF_EMULATE: it is a real mmio page fault, emulate the instruction
 *			directly.
 * RET_MMIO_PF_INVALID: invalid spte is detected then let the real page
 *			fault path update the mmio spte.
 * RET_MMIO_PF_RETRY: let CPU fault again on the address.
 * RET_MMIO_PF_BUG: bug is detected.
 */
enum {
	RET_MMIO_PF_EMULATE = 1,
	RET_MMIO_PF_INVALID = 2,
	RET_MMIO_PF_RETRY = 0,
	RET_MMIO_PF_BUG = -1
};

int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct);
void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
		bool execonly);
void update_permission_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
		bool ept);

static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)
{
	if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages)
		return kvm->arch.n_max_mmu_pages -
			kvm->arch.n_used_mmu_pages;

	return 0;
}

static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
{
	if (likely(vcpu->arch.mmu.root_hpa != INVALID_PAGE))
		return 0;

	return kvm_mmu_load(vcpu);
}

static inline int is_present_gpte(unsigned long pte)
{
	return pte & PT_PRESENT_MASK;
}

static inline int is_writable_pte(unsigned long pte)
{
	return pte & PT_WRITABLE_MASK;
}

static inline bool is_write_protection(struct kvm_vcpu *vcpu)
{
	return kvm_read_cr0_bits(vcpu, X86_CR0_WP);
}

/*
 * Will a fault with a given page-fault error code (pfec) cause a permission
 * fault with the given access (in ACC_* format)?
 */
static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
				    unsigned pte_access, unsigned pfec)
{
	int cpl = kvm_x86_ops->get_cpl(vcpu);
	unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);

	/*
	 * If CPL < 3, SMAP prevention are disabled if EFLAGS.AC = 1.
	 *
	 * If CPL = 3, SMAP applies to all supervisor-mode data accesses
	 * (these are implicit supervisor accesses) regardless of the value
	 * of EFLAGS.AC.
	 *
	 * This computes (cpl < 3) && (rflags & X86_EFLAGS_AC), leaving
	 * the result in X86_EFLAGS_AC. We then insert it in place of
	 * the PFERR_RSVD_MASK bit; this bit will always be zero in pfec,
	 * but it will be one in index if SMAP checks are being overridden.
	 * It is important to keep this branchless.
	 */
	unsigned long smap = (cpl - 3) & (rflags & X86_EFLAGS_AC);
	int index = (pfec >> 1) +
		    (smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1));

	return (mmu->permissions[index] >> pte_access) & 1;
}

void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm);
#endif