1 files changed, 223 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
new file mode 100644
index 000000000..581925e47
--- /dev/null
+++ b/arch/x86/kvm/mmu.h
@@ -0,0 +1,223 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_MMU_H
+#define __KVM_X86_MMU_H
+
+#include <linux/kvm_host.h>
+#include "kvm_cache_regs.h"
+#include "cpuid.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_USER_SHIFT 2
+
+#define PT_PRESENT_MASK (1ULL << 0)
+#define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
+#define PT_USER_MASK (1ULL << PT_USER_SHIFT)
+#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_5LEVEL 5
+#define PT64_ROOT_4LEVEL 4
+#define PT32_ROOT_LEVEL 2
+#define PT32E_ROOT_LEVEL 3
+
+static inline u64 rsvd_bits(int s, int e)
+{
+	if (e < s)
+		return 0;
+
+	return ((2ULL << (e - s)) - 1) << s;
+}
+
+void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 access_mask);
+
+void
+reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
+
+void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots);
+void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
+			     gpa_t nested_cr3);
+void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
+			     bool accessed_dirty, gpa_t new_eptp);
+bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu);
+int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
+				u64 fault_address, char *insn, int insn_len);
+
+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 unsigned long kvm_get_pcid(struct kvm_vcpu *vcpu, gpa_t cr3)
+{
+	BUILD_BUG_ON((X86_CR3_PCID_MASK & PAGE_MASK) != 0);
+
+	return kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)
+	       ? cr3 & X86_CR3_PCID_MASK
+	       : 0;
+}
+
+static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu)
+{
+	return kvm_get_pcid(vcpu, kvm_read_cr3(vcpu));
+}
+
+static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu)
+{
+	u64 root_hpa = vcpu->arch.mmu->root_hpa;
+
+	if (!VALID_PAGE(root_hpa))
+		return;
+
+	kvm_x86_ops.load_mmu_pgd(vcpu, root_hpa | kvm_get_active_pcid(vcpu),
+				 vcpu->arch.mmu->shadow_root_level);
+}
+
+int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
+		       bool prefault);
+
+static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
+					u32 err, bool prefault)
+{
+#ifdef CONFIG_RETPOLINE
+	if (likely(vcpu->arch.mmu->page_fault == kvm_tdp_page_fault))
+		return kvm_tdp_page_fault(vcpu, cr2_or_gpa, err, prefault);
+#endif
+	return vcpu->arch.mmu->page_fault(vcpu, cr2_or_gpa, err, prefault);
+}
+
+/*
+ * Currently, we have two sorts of write-protection, a) the first one
+ * write-protects guest page to sync the guest modification, b) another one is
+ * used to sync dirty bitmap when we do KVM_GET_DIRTY_LOG. The differences
+ * between these two sorts are:
+ * 1) the first case clears SPTE_MMU_WRITEABLE bit.
+ * 2) the first case requires flushing tlb immediately avoiding corrupting
+ *    shadow page table between all vcpus so it should be in the protection of
+ *    mmu-lock. And the another case does not need to flush tlb until returning
+ *    the dirty bitmap to userspace since it only write-protects the page
+ *    logged in the bitmap, that means the page in the dirty bitmap is not
+ *    missed, so it can flush tlb out of mmu-lock.
+ *
+ * So, there is the problem: the first case can meet the corrupted tlb caused
+ * by another case which write-protects pages but without flush tlb
+ * immediately. In order to making the first case be aware this problem we let
+ * it flush tlb if we try to write-protect a spte whose SPTE_MMU_WRITEABLE bit
+ * is set, it works since another case never touches SPTE_MMU_WRITEABLE bit.
+ *
+ * Anyway, whenever a spte is updated (only permission and status bits are
+ * changed) we need to check whether the spte with SPTE_MMU_WRITEABLE becomes
+ * readonly, if that happens, we need to flush tlb. Fortunately,
+ * mmu_spte_update() has already handled it perfectly.
+ *
+ * The rules to use SPTE_MMU_WRITEABLE and PT_WRITABLE_MASK:
+ * - if we want to see if it has writable tlb entry or if the spte can be
+ *   writable on the mmu mapping, check SPTE_MMU_WRITEABLE, this is the most
+ *   case, otherwise
+ * - if we fix page fault on the spte or do write-protection by dirty logging,
+ *   check PT_WRITABLE_MASK.
+ *
+ * TODO: introduce APIs to split these two cases.
+ */
+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);
+}
+
+/*
+ * Check if a given access (described through the I/D, W/R and U/S bits of a
+ * page fault error code pfec) causes a permission fault with the given PTE
+ * access rights (in ACC_* format).
+ *
+ * Return zero if the access does not fault; return the page fault error code
+ * if the access faults.
+ */
+static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
+				  unsigned pte_access, unsigned pte_pkey,
+				  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));
+	bool fault = (mmu->permissions[index] >> pte_access) & 1;
+	u32 errcode = PFERR_PRESENT_MASK;
+
+	WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK));
+	if (unlikely(mmu->pkru_mask)) {
+		u32 pkru_bits, offset;
+
+		/*
+		* PKRU defines 32 bits, there are 16 domains and 2
+		* attribute bits per domain in pkru.  pte_pkey is the
+		* index of the protection domain, so pte_pkey * 2 is
+		* is the index of the first bit for the domain.
+		*/
+		pkru_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3;
+
+		/* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */
+		offset = (pfec & ~1) +
+			((pte_access & PT_USER_MASK) << (PFERR_RSVD_BIT - PT_USER_SHIFT));
+
+		pkru_bits &= mmu->pkru_mask >> offset;
+		errcode |= -pkru_bits & PFERR_PK_MASK;
+		fault |= (pkru_bits != 0);
+	}
+
+	return -(u32)fault & errcode;
+}
+
+void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end);
+
+int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
+
+int kvm_mmu_post_init_vm(struct kvm *kvm);
+void kvm_mmu_pre_destroy_vm(struct kvm *kvm);
+
+#endif