Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 535 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
new file mode 100644
index 000000000..0243b6d22
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -0,0 +1,535 @@
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ARM64_KVM_MMU_H__
+#define __ARM64_KVM_MMU_H__
+
+#include <asm/page.h>
+#include <asm/memory.h>
+#include <asm/cpufeature.h>
+
+/*
+ * As ARMv8.0 only has the TTBR0_EL2 register, we cannot express
+ * "negative" addresses. This makes it impossible to directly share
+ * mappings with the kernel.
+ *
+ * Instead, give the HYP mode its own VA region at a fixed offset from
+ * the kernel by just masking the top bits (which are all ones for a
+ * kernel address). We need to find out how many bits to mask.
+ *
+ * We want to build a set of page tables that cover both parts of the
+ * idmap (the trampoline page used to initialize EL2), and our normal
+ * runtime VA space, at the same time.
+ *
+ * Given that the kernel uses VA_BITS for its entire address space,
+ * and that half of that space (VA_BITS - 1) is used for the linear
+ * mapping, we can also limit the EL2 space to (VA_BITS - 1).
+ *
+ * The main question is "Within the VA_BITS space, does EL2 use the
+ * top or the bottom half of that space to shadow the kernel's linear
+ * mapping?". As we need to idmap the trampoline page, this is
+ * determined by the range in which this page lives.
+ *
+ * If the page is in the bottom half, we have to use the top half. If
+ * the page is in the top half, we have to use the bottom half:
+ *
+ * T = __pa_symbol(__hyp_idmap_text_start)
+ * if (T & BIT(VA_BITS - 1))
+ *	HYP_VA_MIN = 0  //idmap in upper half
+ * else
+ *	HYP_VA_MIN = 1 << (VA_BITS - 1)
+ * HYP_VA_MAX = HYP_VA_MIN + (1 << (VA_BITS - 1)) - 1
+ *
+ * This of course assumes that the trampoline page exists within the
+ * VA_BITS range. If it doesn't, then it means we're in the odd case
+ * where the kernel idmap (as well as HYP) uses more levels than the
+ * kernel runtime page tables (as seen when the kernel is configured
+ * for 4k pages, 39bits VA, and yet memory lives just above that
+ * limit, forcing the idmap to use 4 levels of page tables while the
+ * kernel itself only uses 3). In this particular case, it doesn't
+ * matter which side of VA_BITS we use, as we're guaranteed not to
+ * conflict with anything.
+ *
+ * When using VHE, there are no separate hyp mappings and all KVM
+ * functionality is already mapped as part of the main kernel
+ * mappings, and none of this applies in that case.
+ */
+
+#ifdef __ASSEMBLY__
+
+#include <asm/alternative.h>
+
+/*
+ * Convert a kernel VA into a HYP VA.
+ * reg: VA to be converted.
+ *
+ * The actual code generation takes place in kvm_update_va_mask, and
+ * the instructions below are only there to reserve the space and
+ * perform the register allocation (kvm_update_va_mask uses the
+ * specific registers encoded in the instructions).
+ */
+.macro kern_hyp_va	reg
+alternative_cb kvm_update_va_mask
+	and     \reg, \reg, #1		/* mask with va_mask */
+	ror	\reg, \reg, #1		/* rotate to the first tag bit */
+	add	\reg, \reg, #0		/* insert the low 12 bits of the tag */
+	add	\reg, \reg, #0, lsl 12	/* insert the top 12 bits of the tag */
+	ror	\reg, \reg, #63		/* rotate back */
+alternative_cb_end
+.endm
+
+#else
+
+#include <asm/pgalloc.h>
+#include <asm/cache.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+
+void kvm_update_va_mask(struct alt_instr *alt,
+			__le32 *origptr, __le32 *updptr, int nr_inst);
+
+static inline unsigned long __kern_hyp_va(unsigned long v)
+{
+	asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n"
+				    "ror %0, %0, #1\n"
+				    "add %0, %0, #0\n"
+				    "add %0, %0, #0, lsl 12\n"
+				    "ror %0, %0, #63\n",
+				    kvm_update_va_mask)
+		     : "+r" (v));
+	return v;
+}
+
+#define kern_hyp_va(v) 	((typeof(v))(__kern_hyp_va((unsigned long)(v))))
+
+/*
+ * Obtain the PC-relative address of a kernel symbol
+ * s: symbol
+ *
+ * The goal of this macro is to return a symbol's address based on a
+ * PC-relative computation, as opposed to a loading the VA from a
+ * constant pool or something similar. This works well for HYP, as an
+ * absolute VA is guaranteed to be wrong. Only use this if trying to
+ * obtain the address of a symbol (i.e. not something you obtained by
+ * following a pointer).
+ */
+#define hyp_symbol_addr(s)						\
+	({								\
+		typeof(s) *addr;					\
+		asm("adrp	%0, %1\n"				\
+		    "add	%0, %0, :lo12:%1\n"			\
+		    : "=r" (addr) : "S" (&s));				\
+		addr;							\
+	})
+
+/*
+ * We currently only support a 40bit IPA.
+ */
+#define KVM_PHYS_SHIFT	(40)
+#define KVM_PHYS_SIZE	(1UL << KVM_PHYS_SHIFT)
+#define KVM_PHYS_MASK	(KVM_PHYS_SIZE - 1UL)
+
+#include <asm/stage2_pgtable.h>
+
+int create_hyp_mappings(void *from, void *to, pgprot_t prot);
+int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
+			   void __iomem **kaddr,
+			   void __iomem **haddr);
+int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
+			     void **haddr);
+void free_hyp_pgds(void);
+
+void stage2_unmap_vm(struct kvm *kvm);
+int kvm_alloc_stage2_pgd(struct kvm *kvm);
+void kvm_free_stage2_pgd(struct kvm *kvm);
+int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
+			  phys_addr_t pa, unsigned long size, bool writable);
+
+int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run);
+
+void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
+
+phys_addr_t kvm_mmu_get_httbr(void);
+phys_addr_t kvm_get_idmap_vector(void);
+int kvm_mmu_init(void);
+void kvm_clear_hyp_idmap(void);
+
+#define kvm_mk_pmd(ptep)					\
+	__pmd(__phys_to_pmd_val(__pa(ptep)) | PMD_TYPE_TABLE)
+#define kvm_mk_pud(pmdp)					\
+	__pud(__phys_to_pud_val(__pa(pmdp)) | PMD_TYPE_TABLE)
+#define kvm_mk_pgd(pudp)					\
+	__pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE)
+
+static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
+{
+	pte_val(pte) |= PTE_S2_RDWR;
+	return pte;
+}
+
+static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd)
+{
+	pmd_val(pmd) |= PMD_S2_RDWR;
+	return pmd;
+}
+
+static inline pte_t kvm_s2pte_mkexec(pte_t pte)
+{
+	pte_val(pte) &= ~PTE_S2_XN;
+	return pte;
+}
+
+static inline pmd_t kvm_s2pmd_mkexec(pmd_t pmd)
+{
+	pmd_val(pmd) &= ~PMD_S2_XN;
+	return pmd;
+}
+
+static inline void kvm_set_s2pte_readonly(pte_t *ptep)
+{
+	pteval_t old_pteval, pteval;
+
+	pteval = READ_ONCE(pte_val(*ptep));
+	do {
+		old_pteval = pteval;
+		pteval &= ~PTE_S2_RDWR;
+		pteval |= PTE_S2_RDONLY;
+		pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval);
+	} while (pteval != old_pteval);
+}
+
+static inline bool kvm_s2pte_readonly(pte_t *ptep)
+{
+	return (READ_ONCE(pte_val(*ptep)) & PTE_S2_RDWR) == PTE_S2_RDONLY;
+}
+
+static inline bool kvm_s2pte_exec(pte_t *ptep)
+{
+	return !(READ_ONCE(pte_val(*ptep)) & PTE_S2_XN);
+}
+
+static inline void kvm_set_s2pmd_readonly(pmd_t *pmdp)
+{
+	kvm_set_s2pte_readonly((pte_t *)pmdp);
+}
+
+static inline bool kvm_s2pmd_readonly(pmd_t *pmdp)
+{
+	return kvm_s2pte_readonly((pte_t *)pmdp);
+}
+
+static inline bool kvm_s2pmd_exec(pmd_t *pmdp)
+{
+	return !(READ_ONCE(pmd_val(*pmdp)) & PMD_S2_XN);
+}
+
+static inline bool kvm_page_empty(void *ptr)
+{
+	struct page *ptr_page = virt_to_page(ptr);
+	return page_count(ptr_page) == 1;
+}
+
+#define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
+
+#ifdef __PAGETABLE_PMD_FOLDED
+#define hyp_pmd_table_empty(pmdp) (0)
+#else
+#define hyp_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
+#endif
+
+#ifdef __PAGETABLE_PUD_FOLDED
+#define hyp_pud_table_empty(pudp) (0)
+#else
+#define hyp_pud_table_empty(pudp) kvm_page_empty(pudp)
+#endif
+
+struct kvm;
+
+#define kvm_flush_dcache_to_poc(a,l)	__flush_dcache_area((a), (l))
+
+static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu)
+{
+	return (vcpu_read_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101;
+}
+
+static inline void __clean_dcache_guest_page(kvm_pfn_t pfn, unsigned long size)
+{
+	void *va = page_address(pfn_to_page(pfn));
+
+	/*
+	 * With FWB, we ensure that the guest always accesses memory using
+	 * cacheable attributes, and we don't have to clean to PoC when
+	 * faulting in pages. Furthermore, FWB implies IDC, so cleaning to
+	 * PoU is not required either in this case.
+	 */
+	if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
+		return;
+
+	kvm_flush_dcache_to_poc(va, size);
+}
+
+static inline void __invalidate_icache_guest_page(kvm_pfn_t pfn,
+						  unsigned long size)
+{
+	if (icache_is_aliasing()) {
+		/* any kind of VIPT cache */
+		__flush_icache_all();
+	} else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) {
+		/* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */
+		void *va = page_address(pfn_to_page(pfn));
+
+		invalidate_icache_range((unsigned long)va,
+					(unsigned long)va + size);
+	}
+}
+
+static inline void __kvm_flush_dcache_pte(pte_t pte)
+{
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pte_page(pte);
+		kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE);
+	}
+}
+
+static inline void __kvm_flush_dcache_pmd(pmd_t pmd)
+{
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pmd_page(pmd);
+		kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE);
+	}
+}
+
+static inline void __kvm_flush_dcache_pud(pud_t pud)
+{
+	if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
+		struct page *page = pud_page(pud);
+		kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE);
+	}
+}
+
+#define kvm_virt_to_phys(x)		__pa_symbol(x)
+
+void kvm_set_way_flush(struct kvm_vcpu *vcpu);
+void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);
+
+static inline bool __kvm_cpu_uses_extended_idmap(void)
+{
+	return __cpu_uses_extended_idmap_level();
+}
+
+static inline unsigned long __kvm_idmap_ptrs_per_pgd(void)
+{
+	return idmap_ptrs_per_pgd;
+}
+
+/*
+ * Can't use pgd_populate here, because the extended idmap adds an extra level
+ * above CONFIG_PGTABLE_LEVELS (which is 2 or 3 if we're using the extended
+ * idmap), and pgd_populate is only available if CONFIG_PGTABLE_LEVELS = 4.
+ */
+static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
+				       pgd_t *hyp_pgd,
+				       pgd_t *merged_hyp_pgd,
+				       unsigned long hyp_idmap_start)
+{
+	int idmap_idx;
+	u64 pgd_addr;
+
+	/*
+	 * Use the first entry to access the HYP mappings. It is
+	 * guaranteed to be free, otherwise we wouldn't use an
+	 * extended idmap.
+	 */
+	VM_BUG_ON(pgd_val(merged_hyp_pgd[0]));
+	pgd_addr = __phys_to_pgd_val(__pa(hyp_pgd));
+	merged_hyp_pgd[0] = __pgd(pgd_addr | PMD_TYPE_TABLE);
+
+	/*
+	 * Create another extended level entry that points to the boot HYP map,
+	 * which contains an ID mapping of the HYP init code. We essentially
+	 * merge the boot and runtime HYP maps by doing so, but they don't
+	 * overlap anyway, so this is fine.
+	 */
+	idmap_idx = hyp_idmap_start >> VA_BITS;
+	VM_BUG_ON(pgd_val(merged_hyp_pgd[idmap_idx]));
+	pgd_addr = __phys_to_pgd_val(__pa(boot_hyp_pgd));
+	merged_hyp_pgd[idmap_idx] = __pgd(pgd_addr | PMD_TYPE_TABLE);
+}
+
+static inline unsigned int kvm_get_vmid_bits(void)
+{
+	int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+
+	return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8;
+}
+
+/*
+ * We are not in the kvm->srcu critical section most of the time, so we take
+ * the SRCU read lock here. Since we copy the data from the user page, we
+ * can immediately drop the lock again.
+ */
+static inline int kvm_read_guest_lock(struct kvm *kvm,
+				      gpa_t gpa, void *data, unsigned long len)
+{
+	int srcu_idx = srcu_read_lock(&kvm->srcu);
+	int ret = kvm_read_guest(kvm, gpa, data, len);
+
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+	return ret;
+}
+
+static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
+				       const void *data, unsigned long len)
+{
+	int srcu_idx = srcu_read_lock(&kvm->srcu);
+	int ret = kvm_write_guest(kvm, gpa, data, len);
+
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+	return ret;
+}
+
+#ifdef CONFIG_KVM_INDIRECT_VECTORS
+/*
+ * EL2 vectors can be mapped and rerouted in a number of ways,
+ * depending on the kernel configuration and CPU present:
+ *
+ * - If the CPU has the ARM64_HARDEN_BRANCH_PREDICTOR cap, the
+ *   hardening sequence is placed in one of the vector slots, which is
+ *   executed before jumping to the real vectors.
+ *
+ * - If the CPU has both the ARM64_HARDEN_EL2_VECTORS cap and the
+ *   ARM64_HARDEN_BRANCH_PREDICTOR cap, the slot containing the
+ *   hardening sequence is mapped next to the idmap page, and executed
+ *   before jumping to the real vectors.
+ *
+ * - If the CPU only has the ARM64_HARDEN_EL2_VECTORS cap, then an
+ *   empty slot is selected, mapped next to the idmap page, and
+ *   executed before jumping to the real vectors.
+ *
+ * Note that ARM64_HARDEN_EL2_VECTORS is somewhat incompatible with
+ * VHE, as we don't have hypervisor-specific mappings. If the system
+ * is VHE and yet selects this capability, it will be ignored.
+ */
+#include <asm/mmu.h>
+
+extern void *__kvm_bp_vect_base;
+extern int __kvm_harden_el2_vector_slot;
+
+static inline void *kvm_get_hyp_vector(void)
+{
+	struct bp_hardening_data *data = arm64_get_bp_hardening_data();
+	void *vect = kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
+	int slot = -1;
+
+	if ((cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR) ||
+	     cpus_have_const_cap(ARM64_SPECTRE_BHB)) &&
+	    data && data->template_start) {
+		vect = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs_start));
+		slot = data->hyp_vectors_slot;
+	}
+
+	if (this_cpu_has_cap(ARM64_HARDEN_EL2_VECTORS) && !has_vhe()) {
+		vect = __kvm_bp_vect_base;
+		if (slot == -1)
+			slot = __kvm_harden_el2_vector_slot;
+	}
+
+	if (slot != -1)
+		vect += slot * SZ_2K;
+
+	return vect;
+}
+
+/*  This is only called on a !VHE system */
+static inline int kvm_map_vectors(void)
+{
+	/*
+	 * HBP  = ARM64_HARDEN_BRANCH_PREDICTOR
+	 * HEL2 = ARM64_HARDEN_EL2_VECTORS
+	 *
+	 * !HBP + !HEL2 -> use direct vectors
+	 *  HBP + !HEL2 -> use hardened vectors in place
+	 * !HBP +  HEL2 -> allocate one vector slot and use exec mapping
+	 *  HBP +  HEL2 -> use hardened vertors and use exec mapping
+	 */
+	if (cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR) ||
+	    cpus_have_const_cap(ARM64_SPECTRE_BHB)) {
+		__kvm_bp_vect_base = kvm_ksym_ref(__bp_harden_hyp_vecs_start);
+		__kvm_bp_vect_base = kern_hyp_va(__kvm_bp_vect_base);
+	}
+
+	if (cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS)) {
+		phys_addr_t vect_pa = __pa_symbol(__bp_harden_hyp_vecs_start);
+		unsigned long size = (__bp_harden_hyp_vecs_end -
+				      __bp_harden_hyp_vecs_start);
+
+		/*
+		 * Always allocate a spare vector slot, as we don't
+		 * know yet which CPUs have a BP hardening slot that
+		 * we can reuse.
+		 */
+		__kvm_harden_el2_vector_slot = atomic_inc_return(&arm64_el2_vector_last_slot);
+		BUG_ON(__kvm_harden_el2_vector_slot >= BP_HARDEN_EL2_SLOTS);
+		return create_hyp_exec_mappings(vect_pa, size,
+						&__kvm_bp_vect_base);
+	}
+
+	return 0;
+}
+#else
+static inline void *kvm_get_hyp_vector(void)
+{
+	return kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
+}
+
+static inline int kvm_map_vectors(void)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_ARM64_SSBD
+DECLARE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
+
+static inline int hyp_map_aux_data(void)
+{
+	int cpu, err;
+
+	for_each_possible_cpu(cpu) {
+		u64 *ptr;
+
+		ptr = per_cpu_ptr(&arm64_ssbd_callback_required, cpu);
+		err = create_hyp_mappings(ptr, ptr + 1, PAGE_HYP);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+#else
+static inline int hyp_map_aux_data(void)
+{
+	return 0;
+}
+#endif
+
+#define kvm_phys_to_vttbr(addr)		phys_to_ttbr(addr)
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARM64_KVM_MMU_H__ */