KVM: arm64: Introduce pKVM hyp VM and vCPU state at EL2

index 592b7edb3edb..9422900e5c6a 100644
@@ -38,6 +38,10 @@ static inline phys_addr_t hyp_virt_to_phys(void *addr)
 #define hyp_page_to_virt(page)	__hyp_va(hyp_page_to_phys(page))
 #define hyp_page_to_pool(page)	(((struct hyp_page *)page)->pool)
 
+/*
+ * Refcounting for 'struct hyp_page'.
+ * hyp_pool::lock must be held if atomic access to the refcount is required.
+ */
 static inline int hyp_page_count(void *addr)
 {
 	struct hyp_page *p = hyp_virt_to_page(addr);

@@ -45,4 +49,22 @@ static inline int hyp_page_count(void *addr)
 	return p->refcount;
 }
 
+static inline void hyp_page_ref_inc(struct hyp_page *p)
+{
+	BUG_ON(p->refcount == USHRT_MAX);
+	p->refcount++;
+}
+
+static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
+{
+	BUG_ON(!p->refcount);
+	p->refcount--;
+	return (p->refcount == 0);
+}
+
+static inline void hyp_set_page_refcounted(struct hyp_page *p)
+{
+	BUG_ON(p->refcount);
+	p->refcount = 1;
+}
 #endif /* __KVM_HYP_MEMORY_H */

index d40f0b30b534..1ded09fc9b10 100644
@@ -144,25 +144,6 @@ static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool,
 	return p;
 }
 
-static inline void hyp_page_ref_inc(struct hyp_page *p)
-{
-	BUG_ON(p->refcount == USHRT_MAX);
-	p->refcount++;
-}
-
-static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
-{
-	BUG_ON(!p->refcount);
-	p->refcount--;
-	return (p->refcount == 0);
-}
-
-static inline void hyp_set_page_refcounted(struct hyp_page *p)
-{
-	BUG_ON(p->refcount);
-	p->refcount = 1;
-}
-
 static void __hyp_put_page(struct hyp_pool *pool, struct hyp_page *p)
 {
 	if (hyp_page_ref_dec_and_test(p))

index 1ded09fc9b10..0d15227aced8 100644
@@ -93,11 +93,15 @@ static inline struct hyp_page *node_to_page(struct list_head *node)
 static void __hyp_attach_page(struct hyp_pool *pool,
 			      struct hyp_page *p)
 {
+	phys_addr_t phys = hyp_page_to_phys(p);
 	unsigned short order = p->order;
 	struct hyp_page *buddy;
 
 	memset(hyp_page_to_virt(p), 0, PAGE_SIZE << p->order);
 
+	if (phys < pool->range_start || phys >= pool->range_end)
+		goto insert;
+
 	/*
 	 * Only the first struct hyp_page of a high-order page (otherwise known
 	 * as the 'head') should have p->order set. The non-head pages should

@@ -116,6 +120,7 @@ static void __hyp_attach_page(struct hyp_pool *pool,
 		p = min(p, buddy);
 	}
 
+insert:
 	/* Mark the new head, and insert it */
 	p->order = order;
 	page_add_to_list(p, &pool->free_area[order]);

index 9f4ad2a8df59..8f7b8a2314bb 100644
@@ -14,6 +14,32 @@
 extern struct memblock_region kvm_nvhe_sym(hyp_memory)[];
 extern unsigned int kvm_nvhe_sym(hyp_memblock_nr);
 
+static inline unsigned long
+hyp_vmemmap_memblock_size(struct memblock_region *reg, size_t vmemmap_entry_size)
+{
+	unsigned long nr_pages = reg->size >> PAGE_SHIFT;
+	unsigned long start, end;
+
+	start = (reg->base >> PAGE_SHIFT) * vmemmap_entry_size;
+	end = start + nr_pages * vmemmap_entry_size;
+	start = ALIGN_DOWN(start, PAGE_SIZE);
+	end = ALIGN(end, PAGE_SIZE);
+
+	return end - start;
+}
+
+static inline unsigned long hyp_vmemmap_pages(size_t vmemmap_entry_size)
+{
+	unsigned long res = 0, i;
+
+	for (i = 0; i < kvm_nvhe_sym(hyp_memblock_nr); i++) {
+		res += hyp_vmemmap_memblock_size(&kvm_nvhe_sym(hyp_memory)[i],
+						 vmemmap_entry_size);
+	}
+
+	return res >> PAGE_SHIFT;
+}
+
 static inline unsigned long __hyp_pgtable_max_pages(unsigned long nr_pages)
 {
 	unsigned long total = 0, i;

index 42d8eb9bfe72..b2ee6d5df55b 100644
@@ -15,7 +15,7 @@ extern hyp_spinlock_t pkvm_pgd_lock;
 
 int hyp_create_idmap(u32 hyp_va_bits);
 int hyp_map_vectors(void);
-int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
+int hyp_back_vmemmap(phys_addr_t back);
 int pkvm_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
 int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
 int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot);

@@ -24,16 +24,4 @@ int __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
 				  unsigned long *haddr);
 int pkvm_alloc_private_va_range(size_t size, unsigned long *haddr);
 
-static inline void hyp_vmemmap_range(phys_addr_t phys, unsigned long size,
-				     unsigned long *start, unsigned long *end)
-{
-	unsigned long nr_pages = size >> PAGE_SHIFT;
-	struct hyp_page *p = hyp_phys_to_page(phys);
-
-	*start = (unsigned long)p;
-	*end = *start + nr_pages * sizeof(struct hyp_page);
-	*start = ALIGN_DOWN(*start, PAGE_SIZE);
-	*end = ALIGN(*end, PAGE_SIZE);
-}
-
 #endif /* __KVM_HYP_MM_H */

index 96193cb31a39..d3a3b47181de 100644
@@ -129,13 +129,36 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
 	return ret;
 }
 
-int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back)
+int hyp_back_vmemmap(phys_addr_t back)
 {
-	unsigned long start, end;
+	unsigned long i, start, size, end = 0;
+	int ret;
 
-	hyp_vmemmap_range(phys, size, &start, &end);
+	for (i = 0; i < hyp_memblock_nr; i++) {
+		start = hyp_memory[i].base;
+		start = ALIGN_DOWN((u64)hyp_phys_to_page(start), PAGE_SIZE);
+		/*
+		 * The begining of the hyp_vmemmap region for the current
+		 * memblock may already be backed by the page backing the end
+		 * the previous region, so avoid mapping it twice.
+		 */
+		start = max(start, end);
+
+		end = hyp_memory[i].base + hyp_memory[i].size;
+		end = PAGE_ALIGN((u64)hyp_phys_to_page(end));
+		if (start >= end)
+			continue;
+
+		size = end - start;
+		ret = __pkvm_create_mappings(start, size, back, PAGE_HYP);
+		if (ret)
+			return ret;
+
+		memset(hyp_phys_to_virt(back), 0, size);
+		back += size;
+	}
 
-	return __pkvm_create_mappings(start, end - start, back, PAGE_HYP);
+	return 0;
 }
 
 static void *__hyp_bp_vect_base;

index 0d15227aced8..7804da89e55d 100644
@@ -235,10 +235,8 @@ int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages,
 
 	/* Init the vmemmap portion */
 	p = hyp_phys_to_page(phys);
-	for (i = 0; i < nr_pages; i++) {
-		p[i].order = 0;
+	for (i = 0; i < nr_pages; i++)
 		hyp_set_page_refcounted(&p[i]);
-	}
 
 	/* Attach the unused pages to the buddy tree */
 	for (i = reserved_pages; i < nr_pages; i++)

index e8d4ea2fcfa0..579eb4f73476 100644
@@ -31,12 +31,11 @@ static struct hyp_pool hpool;
 
 static int divide_memory_pool(void *virt, unsigned long size)
 {
-	unsigned long vstart, vend, nr_pages;
+	unsigned long nr_pages;
 
 	hyp_early_alloc_init(virt, size);
 
-	hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
-	nr_pages = (vend - vstart) >> PAGE_SHIFT;
+	nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page));
 	vmemmap_base = hyp_early_alloc_contig(nr_pages);
 	if (!vmemmap_base)
 		return -ENOMEM;

@@ -78,7 +77,7 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
 	if (ret)
 		return ret;
 
-	ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
+	ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base));
 	if (ret)
 		return ret;
 

index ebecb7c045f4..34229425b25d 100644
@@ -53,7 +53,7 @@ static int __init register_memblock_regions(void)
 
 void __init kvm_hyp_reserve(void)
 {
-	u64 nr_pages, prev, hyp_mem_pages = 0;
+	u64 hyp_mem_pages = 0;
 	int ret;
 
 	if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())

@@ -71,21 +71,7 @@ void __init kvm_hyp_reserve(void)
 
 	hyp_mem_pages += hyp_s1_pgtable_pages();
 	hyp_mem_pages += host_s2_pgtable_pages();
-
-	/*
-	 * The hyp_vmemmap needs to be backed by pages, but these pages
-	 * themselves need to be present in the vmemmap, so compute the number
-	 * of pages needed by looking for a fixed point.
-	 */
-	nr_pages = 0;
-	do {
-		prev = nr_pages;
-		nr_pages = hyp_mem_pages + prev;
-		nr_pages = DIV_ROUND_UP(nr_pages * STRUCT_HYP_PAGE_SIZE,
-					PAGE_SIZE);
-		nr_pages += __hyp_pgtable_max_pages(nr_pages);
-	} while (nr_pages != prev);
-	hyp_mem_pages += nr_pages;
+	hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
 
 	/*
 	 * Try to allocate a PMD-aligned region to reduce TLB pressure once

index 579eb4f73476..8f2726d7e201 100644
@@ -185,12 +185,11 @@ static void hpool_put_page(void *addr)
 	hyp_put_page(&hpool, addr);
 }
 
-static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
-					 kvm_pte_t *ptep,
-					 enum kvm_pgtable_walk_flags flag,
-					 void * const arg)
+static int fix_host_ownership_walker(u64 addr, u64 end, u32 level,
+				     kvm_pte_t *ptep,
+				     enum kvm_pgtable_walk_flags flag,
+				     void * const arg)
 {
-	struct kvm_pgtable_mm_ops *mm_ops = arg;
 	enum kvm_pgtable_prot prot;
 	enum pkvm_page_state state;
 	kvm_pte_t pte = *ptep;

@@ -199,15 +198,6 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
 	if (!kvm_pte_valid(pte))
 		return 0;
 
-	/*
-	 * Fix-up the refcount for the page-table pages as the early allocator
-	 * was unable to access the hyp_vmemmap and so the buddy allocator has
-	 * initialised the refcount to '1'.
-	 */
-	mm_ops->get_page(ptep);
-	if (flag != KVM_PGTABLE_WALK_LEAF)
-		return 0;
-
 	if (level != (KVM_PGTABLE_MAX_LEVELS - 1))
 		return -EINVAL;
 

@@ -236,12 +226,30 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
 	return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
 }
 
-static int finalize_host_mappings(void)
+static int fix_hyp_pgtable_refcnt_walker(u64 addr, u64 end, u32 level,
+					 kvm_pte_t *ptep,
+					 enum kvm_pgtable_walk_flags flag,
+					 void * const arg)
+{
+	struct kvm_pgtable_mm_ops *mm_ops = arg;
+	kvm_pte_t pte = *ptep;
+
+	/*
+	 * Fix-up the refcount for the page-table pages as the early allocator
+	 * was unable to access the hyp_vmemmap and so the buddy allocator has
+	 * initialised the refcount to '1'.
+	 */
+	if (kvm_pte_valid(pte))
+		mm_ops->get_page(ptep);
+
+	return 0;
+}
+
+static int fix_host_ownership(void)
 {
 	struct kvm_pgtable_walker walker = {
-		.cb	= finalize_host_mappings_walker,
-		.flags	= KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
-		.arg	= pkvm_pgtable.mm_ops,
+		.cb	= fix_host_ownership_walker,
+		.flags	= KVM_PGTABLE_WALK_LEAF,
 	};
 	int i, ret;
 

@@ -257,6 +265,18 @@ static int finalize_host_mappings(void)
 	return 0;
 }
 
+static int fix_hyp_pgtable_refcnt(void)
+{
+	struct kvm_pgtable_walker walker = {
+		.cb	= fix_hyp_pgtable_refcnt_walker,
+		.flags	= KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
+		.arg	= pkvm_pgtable.mm_ops,
+	};
+
+	return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits),
+				&walker);
+}
+
 void __noreturn __pkvm_init_finalise(void)
 {
 	struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);

@@ -286,7 +306,11 @@ void __noreturn __pkvm_init_finalise(void)
 	};
 	pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
 
-	ret = finalize_host_mappings();
+	ret = fix_host_ownership();
+	if (ret)
+		goto out;
+
+	ret = fix_hyp_pgtable_refcnt();
 	if (ret)
 		goto out;
 

index 80e99836eac7..f5705a1e972f 100644
@@ -51,7 +51,11 @@ struct host_kvm {
 };
 extern struct host_kvm host_kvm;
 
-extern const u8 pkvm_hyp_id;
+/* This corresponds to page-table locking order */
+enum pkvm_component_id {
+	PKVM_ID_HOST,
+	PKVM_ID_HYP,
+};
 
 int __pkvm_prot_finalize(void);
 int __pkvm_host_share_hyp(u64 pfn);

index 1e78acf9662e..ff86f5bd230f 100644
@@ -26,8 +26,6 @@ struct host_kvm host_kvm;
 
 static struct hyp_pool host_s2_pool;
 
-const u8 pkvm_hyp_id = 1;
-
 static void host_lock_component(void)
 {
 	hyp_spin_lock(&host_kvm.lock);

@@ -380,12 +378,6 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
 	BUG_ON(ret && ret != -EAGAIN);
 }
 
-/* This corresponds to locking order */
-enum pkvm_component_id {
-	PKVM_ID_HOST,
-	PKVM_ID_HYP,
-};
-
 struct pkvm_mem_transition {
 	u64				nr_pages;
 

index 8f2726d7e201..0312c9c74a5a 100644
@@ -212,7 +212,7 @@ static int fix_host_ownership_walker(u64 addr, u64 end, u32 level,
 	state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
 	switch (state) {
 	case PKVM_PAGE_OWNED:
-		return host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_hyp_id);
+		return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
 	case PKVM_PAGE_SHARED_OWNED:
 		prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
 		break;

index f5705a1e972f..c87b19b2d468 100644
@@ -60,6 +60,8 @@ enum pkvm_component_id {
 int __pkvm_prot_finalize(void);
 int __pkvm_host_share_hyp(u64 pfn);
 int __pkvm_host_unshare_hyp(u64 pfn);
+int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
+int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);

284 lines not on this page · raw message

index c30402737548..a7156fd13bc8 100644
@@ -193,7 +193,7 @@ struct kvm_mem_range {
 	u64 end;
 };
 
-static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range)
+static struct memblock_region *find_mem_range(phys_addr_t addr, struct kvm_mem_range *range)
 {
 	int cur, left = 0, right = hyp_memblock_nr;
 	struct memblock_region *reg;

@@ -216,18 +216,28 @@ static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range)
 		} else {
 			range->start = reg->base;
 			range->end = end;
-			return true;
+			return reg;
 		}
 	}
 
-	return false;
+	return NULL;
 }
 
 bool addr_is_memory(phys_addr_t phys)
 {
 	struct kvm_mem_range range;
 
-	return find_mem_range(phys, &range);
+	return !!find_mem_range(phys, &range);
+}
+
+static bool addr_is_allowed_memory(phys_addr_t phys)
+{
+	struct memblock_region *reg;
+	struct kvm_mem_range range;
+
+	reg = find_mem_range(phys, &range);
+
+	return reg && !(reg->flags & MEMBLOCK_NOMAP);
 }
 
 static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)

@@ -346,7 +356,7 @@ static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot pr
 static int host_stage2_idmap(u64 addr)
 {
 	struct kvm_mem_range range;
-	bool is_memory = find_mem_range(addr, &range);
+	bool is_memory = !!find_mem_range(addr, &range);
 	enum kvm_pgtable_prot prot;
 	int ret;
 

@@ -424,7 +434,7 @@ static int __check_page_state_visitor(u64 addr, u64 end, u32 level,
 	struct check_walk_data *d = arg;
 	kvm_pte_t pte = *ptep;
 
-	if (kvm_pte_valid(pte) && !addr_is_memory(kvm_pte_to_phys(pte)))
+	if (kvm_pte_valid(pte) && !addr_is_allowed_memory(kvm_pte_to_phys(pte)))
 		return -EINVAL;
 
 	return d->get_page_state(pte) == d->desired ? 0 : -EPERM;

index c87b19b2d468..998bf165af71 100644
@@ -69,6 +69,9 @@ int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id);
 int kvm_host_prepare_stage2(void *pgt_pool_base);
 void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
 
+int hyp_pin_shared_mem(void *from, void *to);
+void hyp_unpin_shared_mem(void *from, void *to);
+
 static __always_inline void __load_host_stage2(void)
 {
 	if (static_branch_likely(&kvm_protected_mode_initialized))

index 9422900e5c6a..ab205c4d6774 100644
@@ -55,10 +55,15 @@ static inline void hyp_page_ref_inc(struct hyp_page *p)
 	p->refcount++;
 }
 
-static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
+static inline void hyp_page_ref_dec(struct hyp_page *p)
 {
 	BUG_ON(!p->refcount);
 	p->refcount--;
+}
+
+static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
+{
+	hyp_page_ref_dec(p);
 	return (p->refcount == 0);
 }
 

57 lines not on this page · raw message

index 998bf165af71..3bea816296dc 100644
@@ -8,6 +8,7 @@
 #define __KVM_NVHE_MEM_PROTECT__
 #include <linux/kvm_host.h>
 #include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
 #include <asm/virt.h>
 #include <nvhe/spinlock.h>

index 4652fd04bdbe..7c7ea8c55405 100644
@@ -28,9 +28,17 @@ typedef union hyp_spinlock {
 	};
 } hyp_spinlock_t;
 
+#define __HYP_SPIN_LOCK_INITIALIZER \
+	{ .__val = 0 }
+
+#define __HYP_SPIN_LOCK_UNLOCKED \
+	((hyp_spinlock_t) __HYP_SPIN_LOCK_INITIALIZER)
+
+#define DEFINE_HYP_SPINLOCK(x)	hyp_spinlock_t x = __HYP_SPIN_LOCK_UNLOCKED
+
 #define hyp_spin_lock_init(l)						\
 do {									\
-	*(l) = (hyp_spinlock_t){ .__val = 0 };				\
+	*(l) = __HYP_SPIN_LOCK_UNLOCKED;				\
 } while (0)
 
 static inline void hyp_spin_lock(hyp_spinlock_t *lock)

index 3bea816296dc..0a6d3e7f2a43 100644
@@ -44,13 +44,13 @@ static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
 	return prot & PKVM_PAGE_STATE_PROT_MASK;
 }
 
-struct host_kvm {
+struct host_mmu {
 	struct kvm_arch arch;
 	struct kvm_pgtable pgt;
 	struct kvm_pgtable_mm_ops mm_ops;
 	hyp_spinlock_t lock;
 };
-extern struct host_kvm host_kvm;
+extern struct host_mmu host_mmu;
 
 /* This corresponds to page-table locking order */
 enum pkvm_component_id {

@@ -76,7 +76,7 @@ void hyp_unpin_shared_mem(void *from, void *to);
 static __always_inline void __load_host_stage2(void)
 {
 	if (static_branch_likely(&kvm_protected_mode_initialized))
-		__load_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
+		__load_stage2(&host_mmu.arch.mmu, &host_mmu.arch);
 	else
 		write_sysreg(0, vttbr_el2);
 }

143 lines not on this page · raw message

index 53035763e48e..de52ba775d48 100644
@@ -76,6 +76,9 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs,
 	__KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs,
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_init_traps,
+	__KVM_HOST_SMCCC_FUNC___pkvm_init_vm,
+	__KVM_HOST_SMCCC_FUNC___pkvm_init_vcpu,
+	__KVM_HOST_SMCCC_FUNC___pkvm_teardown_vm,
 };
 
 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]

index 45e2136322ba..d3dd7ab9c79e 100644
@@ -115,6 +115,8 @@ struct kvm_smccc_features {
 	unsigned long vendor_hyp_bmap;
 };
 
+typedef unsigned int pkvm_handle_t;
+
 struct kvm_arch {
 	struct kvm_s2_mmu mmu;
 

@@ -166,6 +168,12 @@ struct kvm_arch {
 
 	/* Hypercall features firmware registers' descriptor */
 	struct kvm_smccc_features smccc_feat;
+
+	/*
+	 * For an untrusted host VM, 'pkvm_handle' is used to lookup
+	 * the associated pKVM instance in the hypervisor.
+	 */
+	pkvm_handle_t pkvm_handle;
 };
 
 struct kvm_vcpu_fault_info {

index 1b098bd4cd37..4f6d79fe4352 100644
@@ -288,6 +288,14 @@ u64 kvm_pgtable_hyp_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size);
  */
 u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift);
 
+/**
+ * kvm_pgtable_stage2_pgd_size() - Helper to compute size of a stage-2 PGD
+ * @vtcr:	Content of the VTCR register.
+ *
+ * Return: the size (in bytes) of the stage-2 PGD
+ */
+size_t kvm_pgtable_stage2_pgd_size(u64 vtcr);
+
 /**
  * __kvm_pgtable_stage2_init() - Initialise a guest stage-2 page-table.
  * @pgt:	Uninitialised page-table structure to initialise.

index 8f7b8a2314bb..e22856cf4207 100644
@@ -9,6 +9,9 @@
 #include <linux/memblock.h>
 #include <asm/kvm_pgtable.h>
 
+/* Maximum number of protected VMs that can be created. */
+#define KVM_MAX_PVMS 255
+
 #define HYP_MEMBLOCK_REGIONS 128
 
 extern struct memblock_region kvm_nvhe_sym(hyp_memory)[];

@@ -40,6 +43,11 @@ static inline unsigned long hyp_vmemmap_pages(size_t vmemmap_entry_size)
 	return res >> PAGE_SHIFT;
 }
 
+static inline unsigned long hyp_vm_table_pages(void)
+{
+	return PAGE_ALIGN(KVM_MAX_PVMS * sizeof(void *)) >> PAGE_SHIFT;
+}
+
 static inline unsigned long __hyp_pgtable_max_pages(unsigned long nr_pages)
 {
 	unsigned long total = 0, i;

index 0a6d3e7f2a43..ce9a796a85ee 100644
@@ -11,6 +11,7 @@
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
 #include <asm/virt.h>
+#include <nvhe/pkvm.h>
 #include <nvhe/spinlock.h>
 
 /*

@@ -68,10 +69,12 @@ bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
 int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id);
 int kvm_host_prepare_stage2(void *pgt_pool_base);
+int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd);
 void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
 
 int hyp_pin_shared_mem(void *from, void *to);
 void hyp_unpin_shared_mem(void *from, void *to);
+void reclaim_guest_pages(struct pkvm_hyp_vm *vm);
 
 static __always_inline void __load_host_stage2(void)
 {

64 lines not on this page · raw message

index 3cea4b6ac23e..b5f3fcfe9135 100644
@@ -15,6 +15,7 @@
 
 #include <nvhe/mem_protect.h>
 #include <nvhe/mm.h>
+#include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
 DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);

@@ -191,6 +192,33 @@ static void handle___pkvm_vcpu_init_traps(struct kvm_cpu_context *host_ctxt)
 	__pkvm_vcpu_init_traps(kern_hyp_va(vcpu));
 }
 
+static void handle___pkvm_init_vm(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(struct kvm *, host_kvm, host_ctxt, 1);
+	DECLARE_REG(unsigned long, vm_hva, host_ctxt, 2);
+	DECLARE_REG(unsigned long, pgd_hva, host_ctxt, 3);
+
+	host_kvm = kern_hyp_va(host_kvm);
+	cpu_reg(host_ctxt, 1) = __pkvm_init_vm(host_kvm, vm_hva, pgd_hva);
+}
+
+static void handle___pkvm_init_vcpu(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	DECLARE_REG(struct kvm_vcpu *, host_vcpu, host_ctxt, 2);
+	DECLARE_REG(unsigned long, vcpu_hva, host_ctxt, 3);
+
+	host_vcpu = kern_hyp_va(host_vcpu);
+	cpu_reg(host_ctxt, 1) = __pkvm_init_vcpu(handle, host_vcpu, vcpu_hva);
+}
+
+static void handle___pkvm_teardown_vm(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+
+	cpu_reg(host_ctxt, 1) = __pkvm_teardown_vm(handle);
+}
+
 typedef void (*hcall_t)(struct kvm_cpu_context *);
 
 #define HANDLE_FUNC(x)	[__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x

@@ -220,6 +248,9 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__vgic_v3_save_aprs),
 	HANDLE_FUNC(__vgic_v3_restore_aprs),
 	HANDLE_FUNC(__pkvm_vcpu_init_traps),
+	HANDLE_FUNC(__pkvm_init_vm),
+	HANDLE_FUNC(__pkvm_init_vcpu),
+	HANDLE_FUNC(__pkvm_teardown_vm),
 };
 
 static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)

index bec8306c2392..2ef6aaa21ba5 100644
@@ -141,6 +141,20 @@ int kvm_host_prepare_stage2(void *pgt_pool_base)
 	return 0;
 }
 
+int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd)
+{
+	vm->pgt.pgd = pgd;
+	return 0;
+}
+
+void reclaim_guest_pages(struct pkvm_hyp_vm *vm)
+{
+	unsigned long nr_pages;
+
+	nr_pages = kvm_pgtable_stage2_pgd_size(vm->kvm.arch.vtcr) >> PAGE_SHIFT;
+	WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(vm->pgt.pgd), nr_pages));
+}
+
 int __pkvm_prot_finalize(void)
 {
 	struct kvm_s2_mmu *mmu = &host_mmu.arch.mmu;

398 lines not on this page · raw message

index 0312c9c74a5a..2be72fbe7279 100644
@@ -16,6 +16,7 @@
 #include <nvhe/memory.h>
 #include <nvhe/mem_protect.h>
 #include <nvhe/mm.h>
+#include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
 unsigned long hyp_nr_cpus;

@@ -24,6 +25,7 @@ unsigned long hyp_nr_cpus;
 			 (unsigned long)__per_cpu_start)
 
 static void *vmemmap_base;
+static void *vm_table_base;
 static void *hyp_pgt_base;
 static void *host_s2_pgt_base;
 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;

@@ -40,6 +42,11 @@ static int divide_memory_pool(void *virt, unsigned long size)
 	if (!vmemmap_base)
 		return -ENOMEM;
 
+	nr_pages = hyp_vm_table_pages();
+	vm_table_base = hyp_early_alloc_contig(nr_pages);
+	if (!vm_table_base)
+		return -ENOMEM;
+
 	nr_pages = hyp_s1_pgtable_pages();
 	hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
 	if (!hyp_pgt_base)

@@ -314,6 +321,7 @@ void __noreturn __pkvm_init_finalise(void)
 	if (ret)
 		goto out;
 
+	pkvm_hyp_vm_table_init(vm_table_base);
 out:
 	/*
 	 * We tail-called to here from handle___pkvm_init() and will not return,

index cdf8e76b0be1..a1a27f88a312 100644
@@ -1200,6 +1200,15 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
 	return 0;
 }
 
+size_t kvm_pgtable_stage2_pgd_size(u64 vtcr)
+{
+	u32 ia_bits = VTCR_EL2_IPA(vtcr);
+	u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
+	u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
+
+	return kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
+}
+
 static int stage2_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 			      enum kvm_pgtable_walk_flags flag,
 			      void * const arg)

index 34229425b25d..71493136e59c 100644
@@ -71,6 +71,7 @@ void __init kvm_hyp_reserve(void)
 
 	hyp_mem_pages += hyp_s1_pgtable_pages();
 	hyp_mem_pages += host_s2_pgtable_pages();
+	hyp_mem_pages += hyp_vm_table_pages();
 	hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
 
 	/*

index d3dd7ab9c79e..f09b422ba1fe 100644
@@ -117,6 +117,17 @@ struct kvm_smccc_features {
 
 typedef unsigned int pkvm_handle_t;
 
+struct kvm_protected_vm {
+	pkvm_handle_t handle;
+	struct mutex vm_lock;
+
+	struct {
+		void *pgd;
+		void *vm;
+		void *vcpus[KVM_MAX_VCPUS];
+	} hyp_donations;
+};
+
 struct kvm_arch {
 	struct kvm_s2_mmu mmu;
 

@@ -170,10 +181,10 @@ struct kvm_arch {
 	struct kvm_smccc_features smccc_feat;
 
 	/*
-	 * For an untrusted host VM, 'pkvm_handle' is used to lookup
+	 * For an untrusted host VM, 'pkvm.handle' is used to lookup
 	 * the associated pKVM instance in the hypervisor.
 	 */
-	pkvm_handle_t pkvm_handle;
+	struct kvm_protected_vm pkvm;
 };
 
 struct kvm_vcpu_fault_info {

index e22856cf4207..8340798b2289 100644
@@ -14,6 +14,10 @@
 
 #define HYP_MEMBLOCK_REGIONS 128
 
+int pkvm_init_host_vm(struct kvm *kvm);
+int pkvm_create_hyp_vm(struct kvm *kvm);
+void pkvm_destroy_hyp_vm(struct kvm *kvm);
+
 extern struct memblock_region kvm_nvhe_sym(hyp_memory)[];
 extern unsigned int kvm_nvhe_sym(hyp_memblock_nr);
 

index 94d33e296e10..30d6fc5d3a93 100644
@@ -37,6 +37,7 @@
 #include <asm/kvm_arm.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_mmu.h>
+#include <asm/kvm_pkvm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/sections.h>
 

@@ -150,6 +151,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (ret)
 		goto out_free_stage2_pgd;
 
+	ret = pkvm_init_host_vm(kvm);
+	if (ret)
+		goto out_free_stage2_pgd;
+
 	if (!zalloc_cpumask_var(&kvm->arch.supported_cpus, GFP_KERNEL)) {
 		ret = -ENOMEM;
 		goto out_free_stage2_pgd;

@@ -187,6 +192,9 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 
 	kvm_vgic_destroy(kvm);
 
+	if (is_protected_kvm_enabled())
+		pkvm_destroy_hyp_vm(kvm);
+
 	kvm_destroy_vcpus(kvm);
 
 	kvm_unshare_hyp(kvm, kvm + 1);

@@ -569,6 +577,12 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
+	if (is_protected_kvm_enabled()) {
+		ret = pkvm_create_hyp_vm(kvm);
+		if (ret)
+			return ret;
+	}
+
 	if (!irqchip_in_kernel(kvm)) {
 		/*
 		 * Tell the rest of the code that there are userspace irqchip

index b3742a6691e8..b257a3b4bfc5 100644
@@ -2,9 +2,12 @@
 
 #include <linux/kbuild.h>
 #include <nvhe/memory.h>
+#include <nvhe/pkvm.h>
 
 int main(void)
 {
 	DEFINE(STRUCT_HYP_PAGE_SIZE,	sizeof(struct hyp_page));
+	DEFINE(PKVM_HYP_VM_SIZE,	sizeof(struct pkvm_hyp_vm));
+	DEFINE(PKVM_HYP_VCPU_SIZE,	sizeof(struct pkvm_hyp_vcpu));
 	return 0;
 }

index 7e6f7d2f7713..5970fd1adbfb 100644
@@ -335,7 +335,7 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm,
 	if (idx < 0)
 		return idx;
 
-	hyp_vm->kvm.arch.pkvm_handle = idx_to_vm_handle(idx);
+	hyp_vm->kvm.arch.pkvm.handle = idx_to_vm_handle(idx);
 	hyp_vm->donated_memory_size = donated_memory_size;
 
 	/* VMID 0 is reserved for the host */

@@ -345,7 +345,7 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm,
 	mmu->pgt = &hyp_vm->pgt;
 
 	vm_table[idx] = hyp_vm;
-	return hyp_vm->kvm.arch.pkvm_handle;
+	return hyp_vm->kvm.arch.pkvm.handle;
 }
 
 /*

@@ -470,10 +470,10 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
 		goto err_remove_vm_table_entry;
 	hyp_spin_unlock(&vm_table_lock);
 
-	return hyp_vm->kvm.arch.pkvm_handle;
+	return hyp_vm->kvm.arch.pkvm.handle;
 
 err_remove_vm_table_entry:
-	remove_vm_table_entry(hyp_vm->kvm.arch.pkvm_handle);
+	remove_vm_table_entry(hyp_vm->kvm.arch.pkvm.handle);
 err_unlock:
 	hyp_spin_unlock(&vm_table_lock);
 err_remove_mappings:

@@ -539,6 +539,7 @@ int __pkvm_init_vcpu(pkvm_handle_t handle, struct kvm_vcpu *host_vcpu,
 int __pkvm_teardown_vm(pkvm_handle_t handle)
 {
 	struct pkvm_hyp_vm *hyp_vm;
+	unsigned int idx;
 	int err;
 
 	hyp_spin_lock(&vm_table_lock);

@@ -565,6 +566,12 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
 	/* Push the metadata pages to the teardown memcache */
 	hyp_unpin_shared_mem(hyp_vm->host_kvm, hyp_vm->host_kvm + 1);
 
+	for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) {
+		struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx];
+
+		unmap_donated_memory(hyp_vcpu, sizeof(*hyp_vcpu));
+	}
+
 	unmap_donated_memory(hyp_vm, hyp_vm->donated_memory_size);
 	return 0;
 

147 lines not on this page · raw message

index 4f6d79fe4352..b2a886c9e78d 100644
@@ -30,6 +30,8 @@ typedef u64 kvm_pte_t;
 #define KVM_PTE_ADDR_MASK		GENMASK(47, PAGE_SHIFT)
 #define KVM_PTE_ADDR_51_48		GENMASK(15, 12)
 
+#define KVM_PHYS_INVALID		(-1ULL)
+
 static inline bool kvm_pte_valid(kvm_pte_t pte)
 {
 	return pte & KVM_PTE_VALID;

@@ -45,6 +47,18 @@ static inline u64 kvm_pte_to_phys(kvm_pte_t pte)
 	return pa;
 }
 
+static inline kvm_pte_t kvm_phys_to_pte(u64 pa)
+{
+	kvm_pte_t pte = pa & KVM_PTE_ADDR_MASK;
+
+	if (PAGE_SHIFT == 16) {
+		pa &= GENMASK(51, 48);
+		pte |= FIELD_PREP(KVM_PTE_ADDR_51_48, pa >> 48);
+	}
+
+	return pte;
+}
+
 static inline u64 kvm_granule_shift(u32 level)
 {
 	/* Assumes KVM_PGTABLE_MAX_LEVELS is 4 */

index ce9a796a85ee..ef31a1872c93 100644
@@ -59,6 +59,8 @@ enum pkvm_component_id {
 	PKVM_ID_HYP,
 };
 
+extern unsigned long hyp_nr_cpus;
+
 int __pkvm_prot_finalize(void);
 int __pkvm_host_share_hyp(u64 pfn);
 int __pkvm_host_unshare_hyp(u64 pfn);

index b2ee6d5df55b..d5ec972b5c1e 100644
@@ -13,6 +13,10 @@
 extern struct kvm_pgtable pkvm_pgtable;
 extern hyp_spinlock_t pkvm_pgd_lock;
 
+int hyp_create_pcpu_fixmap(void);
+void *hyp_fixmap_map(phys_addr_t phys);
+void hyp_fixmap_unmap(void);
+
 int hyp_create_idmap(u32 hyp_va_bits);
 int hyp_map_vectors(void);
 int hyp_back_vmemmap(phys_addr_t back);

index 2ef6aaa21ba5..1c38451050e5 100644
@@ -21,7 +21,6 @@
 
 #define KVM_HOST_S2_FLAGS (KVM_PGTABLE_S2_NOFWB | KVM_PGTABLE_S2_IDMAP)
 
-extern unsigned long hyp_nr_cpus;
 struct host_mmu host_mmu;
 
 static struct hyp_pool host_s2_pool;

112 lines not on this page · raw message

index 2be72fbe7279..0f69c1393416 100644
@@ -321,6 +321,10 @@ void __noreturn __pkvm_init_finalise(void)
 	if (ret)
 		goto out;
 
+	ret = hyp_create_pcpu_fixmap();
+	if (ret)
+		goto out;
+
 	pkvm_hyp_vm_table_init(vm_table_base);
 out:
 	/*

index a1a27f88a312..2bcb2d5903ba 100644
@@ -57,8 +57,6 @@ struct kvm_pgtable_walk_data {
 	u64				end;
 };
 
-#define KVM_PHYS_INVALID (-1ULL)
-
 static bool kvm_phys_is_valid(u64 phys)
 {
 	return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_EL1_PARANGE_MAX));

@@ -122,16 +120,6 @@ static bool kvm_pte_table(kvm_pte_t pte, u32 level)
 	return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE;
 }
 
-static kvm_pte_t kvm_phys_to_pte(u64 pa)
-{
-	kvm_pte_t pte = pa & KVM_PTE_ADDR_MASK;
-
-	if (PAGE_SHIFT == 16)
-		pte |= FIELD_PREP(KVM_PTE_ADDR_51_48, pa >> 48);
-
-	return pte;
-}
-
 static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops)
 {
 	return mm_ops->phys_to_virt(kvm_pte_to_phys(pte));

index 30d6fc5d3a93..584626e11797 100644
@@ -1884,11 +1884,8 @@ static int do_pkvm_init(u32 hyp_va_bits)
 	return ret;
 }
 
-static int kvm_hyp_init_protection(u32 hyp_va_bits)
+static void kvm_hyp_init_symbols(void)
 {
-	void *addr = phys_to_virt(hyp_mem_base);
-	int ret;
-
 	kvm_nvhe_sym(id_aa64pfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
 	kvm_nvhe_sym(id_aa64pfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
 	kvm_nvhe_sym(id_aa64isar0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64ISAR0_EL1);

@@ -1897,6 +1894,12 @@ static int kvm_hyp_init_protection(u32 hyp_va_bits)
 	kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
 	kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1);
+}
+
+static int kvm_hyp_init_protection(u32 hyp_va_bits)
+{
+	void *addr = phys_to_virt(hyp_mem_base);
+	int ret;
 
 	ret = create_hyp_mappings(addr, addr + hyp_mem_size, PAGE_HYP);
 	if (ret)

@@ -2071,6 +2074,8 @@ static int init_hyp_mode(void)
 		cpu_prepare_hyp_mode(cpu);
 	}
 
+	kvm_hyp_init_symbols();
+
 	if (is_protected_kvm_enabled()) {
 		init_cpu_logical_map();
 

@@ -2078,9 +2083,7 @@ static int init_hyp_mode(void)
 			err = -ENODEV;
 			goto out_err;
 		}
-	}
 
-	if (is_protected_kvm_enabled()) {
 		err = kvm_hyp_init_protection(hyp_va_bits);
 		if (err) {
 			kvm_err("Failed to init hyp memory protection\n");

index aa7fa2a08f06..fd99cf09972d 100644
@@ -123,4 +123,5 @@ extern u64 kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val);
 extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val);
 extern u64 kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val);
 
+extern unsigned long kvm_nvhe_sym(__icache_flags);
 #endif /* __ARM64_KVM_HYP_H__ */

index 8151412653de..7f4e43bfaade 100644
@@ -71,9 +71,6 @@ KVM_NVHE_ALIAS(nvhe_hyp_panic_handler);
 /* Vectors installed by hyp-init on reset HVC. */
 KVM_NVHE_ALIAS(__hyp_stub_vectors);
 
-/* Kernel symbol used by icache_is_vpipt(). */
-KVM_NVHE_ALIAS(__icache_flags);
-
 /* VMID bits set by the KVM VMID allocator */
 KVM_NVHE_ALIAS(kvm_arm_vmid_bits);
 

index 584626e11797..d99e93e6ddf7 100644
@@ -1894,6 +1894,7 @@ static void kvm_hyp_init_symbols(void)
 	kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
 	kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1);
+	kvm_nvhe_sym(__icache_flags) = __icache_flags;
 }
 
 static int kvm_hyp_init_protection(u32 hyp_va_bits)

index 5970fd1adbfb..2156ce546d90 100644
@@ -12,6 +12,9 @@
 #include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
+/* Used by icache_is_vpipt(). */
+unsigned long __icache_flags;
+
 /*
  * Set trap register values based on features in ID_AA64PFR0.
  */

index f09b422ba1fe..2ec268cc2031 100644
@@ -73,6 +73,63 @@ u32 __attribute_const__ kvm_target_cpu(void);
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
 void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
 
+struct kvm_hyp_memcache {
+	phys_addr_t head;
+	unsigned long nr_pages;
+};
+
+static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc,
+				     phys_addr_t *p,
+				     phys_addr_t (*to_pa)(void *virt))
+{
+	*p = mc->head;
+	mc->head = to_pa(p);
+	mc->nr_pages++;
+}
+
+static inline void *pop_hyp_memcache(struct kvm_hyp_memcache *mc,
+				     void *(*to_va)(phys_addr_t phys))
+{
+	phys_addr_t *p = to_va(mc->head);
+
+	if (!mc->nr_pages)
+		return NULL;
+
+	mc->head = *p;
+	mc->nr_pages--;
+
+	return p;
+}
+
+static inline int __topup_hyp_memcache(struct kvm_hyp_memcache *mc,
+				       unsigned long min_pages,
+				       void *(*alloc_fn)(void *arg),
+				       phys_addr_t (*to_pa)(void *virt),
+				       void *arg)
+{
+	while (mc->nr_pages < min_pages) {
+		phys_addr_t *p = alloc_fn(arg);
+
+		if (!p)
+			return -ENOMEM;
+		push_hyp_memcache(mc, p, to_pa);
+	}
+
+	return 0;
+}
+
+static inline void __free_hyp_memcache(struct kvm_hyp_memcache *mc,
+				       void (*free_fn)(void *virt, void *arg),
+				       void *(*to_va)(phys_addr_t phys),
+				       void *arg)
+{
+	while (mc->nr_pages)
+		free_fn(pop_hyp_memcache(mc, to_va), arg);
+}
+
+void free_hyp_memcache(struct kvm_hyp_memcache *mc);
+int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages);
+
 struct kvm_vmid {
 	atomic64_t id;
 };

index ef31a1872c93..420b87e755a4 100644
@@ -77,6 +77,8 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
 int hyp_pin_shared_mem(void *from, void *to);
 void hyp_unpin_shared_mem(void *from, void *to);
 void reclaim_guest_pages(struct pkvm_hyp_vm *vm);
+int refill_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages,
+		    struct kvm_hyp_memcache *host_mc);
 
 static __always_inline void __load_host_stage2(void)
 {

index b77215630d5c..c73f87f13e29 100644
@@ -330,3 +330,36 @@ int hyp_create_idmap(u32 hyp_va_bits)
 
 	return __pkvm_create_mappings(start, end - start, start, PAGE_HYP_EXEC);
 }
+
+static void *admit_host_page(void *arg)
+{
+	struct kvm_hyp_memcache *host_mc = arg;
+
+	if (!host_mc->nr_pages)
+		return NULL;
+
+	/*
+	 * The host still owns the pages in its memcache, so we need to go
+	 * through a full host-to-hyp donation cycle to change it. Fortunately,
+	 * __pkvm_host_donate_hyp() takes care of races for us, so if it
+	 * succeeds we're good to go.
+	 */
+	if (__pkvm_host_donate_hyp(hyp_phys_to_pfn(host_mc->head), 1))
+		return NULL;
+
+	return pop_hyp_memcache(host_mc, hyp_phys_to_virt);
+}
+
+/* Refill our local memcache by poping pages from the one provided by the host. */
+int refill_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages,
+		    struct kvm_hyp_memcache *host_mc)
+{
+	struct kvm_hyp_memcache tmp = *host_mc;
+	int ret;
+
+	ret =  __topup_hyp_memcache(mc, min_pages, admit_host_page,
+				    hyp_virt_to_phys, &tmp);
+	*host_mc = tmp;
+
+	return ret;
+}

index 34c5feed9dc1..8b52566d1cb9 100644
@@ -800,6 +800,32 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 	}
 }
 
+static void hyp_mc_free_fn(void *addr, void *unused)
+{
+	free_page((unsigned long)addr);
+}
+
+static void *hyp_mc_alloc_fn(void *unused)
+{
+	return (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
+}
+
+void free_hyp_memcache(struct kvm_hyp_memcache *mc)
+{
+	if (is_protected_kvm_enabled())
+		__free_hyp_memcache(mc, hyp_mc_free_fn,
+				    kvm_host_va, NULL);
+}
+
+int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
+{
+	if (!is_protected_kvm_enabled())
+		return 0;
+
+	return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn,
+				    kvm_host_pa, NULL);
+}
+
 /**
  * kvm_phys_addr_ioremap - map a device range to guest IPA
  *

index 8aa8492dafc0..89e63585dae4 100644
@@ -135,7 +135,7 @@
  * 40 bits wide (T0SZ = 24).  Systems with a PARange smaller than 40 bits are
  * not known to exist and will break with this configuration.
  *
- * The VTCR_EL2 is configured per VM and is initialised in kvm_arm_setup_stage2().
+ * The VTCR_EL2 is configured per VM and is initialised in kvm_init_stage2_mmu.
  *
  * Note that when using 4K pages, we concatenate two first level page tables
  * together. With 16K pages, we concatenate 16 first level page tables.

index 2ec268cc2031..3fa973237b90 100644
@@ -991,8 +991,6 @@ int kvm_set_ipa_limit(void);
 #define __KVM_HAVE_ARCH_VM_ALLOC
 struct kvm *kvm_arch_alloc_vm(void);
 
-int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type);
-
 static inline bool kvm_vm_is_protected(struct kvm *kvm)
 {
 	return false;

index 7784081088e7..e4a7e6369499 100644
@@ -166,7 +166,7 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
 void free_hyp_pgds(void);
 
 void stage2_unmap_vm(struct kvm *kvm);
-int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu);
+int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type);
 void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu);
 int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 			  phys_addr_t pa, unsigned long size, bool writable);

index d99e93e6ddf7..f78eefa02f6b 100644
@@ -139,28 +139,24 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
 	int ret;
 
-	ret = kvm_arm_setup_stage2(kvm, type);
-	if (ret)
-		return ret;
-
-	ret = kvm_init_stage2_mmu(kvm, &kvm->arch.mmu);
-	if (ret)
-		return ret;
-
 	ret = kvm_share_hyp(kvm, kvm + 1);
 	if (ret)
-		goto out_free_stage2_pgd;
+		return ret;
 
 	ret = pkvm_init_host_vm(kvm);
 	if (ret)
-		goto out_free_stage2_pgd;
+		goto err_unshare_kvm;
 
 	if (!zalloc_cpumask_var(&kvm->arch.supported_cpus, GFP_KERNEL)) {
 		ret = -ENOMEM;
-		goto out_free_stage2_pgd;
+		goto err_unshare_kvm;
 	}
 	cpumask_copy(kvm->arch.supported_cpus, cpu_possible_mask);
 
+	ret = kvm_init_stage2_mmu(kvm, &kvm->arch.mmu, type);
+	if (ret)
+		goto err_free_cpumask;
+
 	kvm_vgic_early_init(kvm);
 
 	/* The maximum number of VCPUs is limited by the host's GIC model */

@@ -169,9 +165,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	set_default_spectre(kvm);
 	kvm_arm_init_hypercalls(kvm);
 
-	return ret;
-out_free_stage2_pgd:
-	kvm_free_stage2_pgd(&kvm->arch.mmu);
+	return 0;
+
+err_free_cpumask:
+	free_cpumask_var(kvm->arch.supported_cpus);
+err_unshare_kvm:
+	kvm_unshare_hyp(kvm, kvm + 1);
 	return ret;
 }
 

index 8b52566d1cb9..43761d31f763 100644
@@ -668,15 +668,40 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
  * kvm_init_stage2_mmu - Initialise a S2 MMU structure
  * @kvm:	The pointer to the KVM structure
  * @mmu:	The pointer to the s2 MMU structure
+ * @type:	The machine type of the virtual machine
  *
  * Allocates only the stage-2 HW PGD level table(s).
  * Note we don't need locking here as this is only called when the VM is
  * created, which can only be done once.
  */
-int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
+int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type)
 {
+	u32 kvm_ipa_limit = get_kvm_ipa_limit();
 	int cpu, err;
 	struct kvm_pgtable *pgt;
+	u64 mmfr0, mmfr1;
+	u32 phys_shift;
+
+	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
+		return -EINVAL;
+
+	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
+	if (phys_shift) {
+		if (phys_shift > kvm_ipa_limit ||
+		    phys_shift < ARM64_MIN_PARANGE_BITS)
+			return -EINVAL;
+	} else {
+		phys_shift = KVM_PHYS_SHIFT;
+		if (phys_shift > kvm_ipa_limit) {
+			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
+				     current->comm);
+			return -EINVAL;
+		}
+	}
+
+	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+	kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
 
 	if (mmu->pgt != NULL) {
 		kvm_err("kvm_arch already initialized?\n");

index 5ae18472205a..e0267f672b8a 100644
@@ -395,32 +395,3 @@ int kvm_set_ipa_limit(void)
 
 	return 0;
 }
-
-int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
-{
-	u64 mmfr0, mmfr1;
-	u32 phys_shift;
-
-	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
-		return -EINVAL;
-
-	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
-	if (phys_shift) {
-		if (phys_shift > kvm_ipa_limit ||
-		    phys_shift < ARM64_MIN_PARANGE_BITS)
-			return -EINVAL;
-	} else {
-		phys_shift = KVM_PHYS_SHIFT;
-		if (phys_shift > kvm_ipa_limit) {
-			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
-				     current->comm);
-			return -EINVAL;
-		}
-	}
-
-	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
-	mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
-	kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
-
-	return 0;
-}

index d176399dbfb5..5d456438445c 100644
@@ -9,6 +9,9 @@
 
 #include <asm/kvm_pkvm.h>
 
+#include <nvhe/gfp.h>
+#include <nvhe/spinlock.h>
+
 /*
  * Holds the relevant data for maintaining the vcpu state completely at hyp.
  */

@@ -36,6 +39,9 @@ struct pkvm_hyp_vm {
 
 	/* The guest's stage-2 page-table managed by the hypervisor. */
 	struct kvm_pgtable pgt;
+	struct kvm_pgtable_mm_ops mm_ops;
+	struct hyp_pool pool;
+	hyp_spinlock_t lock;
 
 	/*
 	 * The number of vcpus initialized and ready to run.

147 lines not on this page · raw message

index 43761d31f763..301fc7275062 100644
@@ -686,7 +686,9 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 		return -EINVAL;
 
 	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
-	if (phys_shift) {
+	if (is_protected_kvm_enabled()) {
+		phys_shift = kvm_ipa_limit;
+	} else if (phys_shift) {
 		if (phys_shift > kvm_ipa_limit ||
 		    phys_shift < ARM64_MIN_PARANGE_BITS)
 			return -EINVAL;

index 3fa973237b90..22a07823b0a9 100644
@@ -177,12 +177,7 @@ typedef unsigned int pkvm_handle_t;
 struct kvm_protected_vm {
 	pkvm_handle_t handle;
 	struct mutex vm_lock;
-
-	struct {
-		void *pgd;
-		void *vm;
-		void *vcpus[KVM_MAX_VCPUS];
-	} hyp_donations;
+	struct kvm_hyp_memcache teardown_mc;
 };
 
 struct kvm_arch {

index 420b87e755a4..b7bdbe63deed 100644
@@ -76,7 +76,7 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
 
 int hyp_pin_shared_mem(void *from, void *to);
 void hyp_unpin_shared_mem(void *from, void *to);
-void reclaim_guest_pages(struct pkvm_hyp_vm *vm);
+void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc);
 int refill_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages,
 		    struct kvm_hyp_memcache *host_mc);
 

index 27b16a6b85bb..ffa56a89acdb 100644
@@ -260,19 +260,24 @@ int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd)
 	return 0;
 }
 
-void reclaim_guest_pages(struct pkvm_hyp_vm *vm)
+void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc)
 {
-	void *pgd = vm->pgt.pgd;
-	unsigned long nr_pages;
-
-	nr_pages = kvm_pgtable_stage2_pgd_size(vm->kvm.arch.vtcr) >> PAGE_SHIFT;
+	void *addr;
 
+	/* Dump all pgtable pages in the hyp_pool */
 	guest_lock_component(vm);
 	kvm_pgtable_stage2_destroy(&vm->pgt);
 	vm->kvm.arch.mmu.pgd_phys = 0ULL;
 	guest_unlock_component(vm);
 
-	WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(pgd), nr_pages));
+	/* Drain the hyp_pool into the memcache */
+	addr = hyp_alloc_pages(&vm->pool, 0);
+	while (addr) {
+		memset(hyp_virt_to_page(addr), 0, sizeof(struct hyp_page));
+		push_hyp_memcache(mc, addr, hyp_virt_to_phys);
+		WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(addr), 1));
+		addr = hyp_alloc_pages(&vm->pool, 0);
+	}
 }
 
 int __pkvm_prot_finalize(void)

index 2156ce546d90..f5f300cc5864 100644
@@ -539,8 +539,21 @@ int __pkvm_init_vcpu(pkvm_handle_t handle, struct kvm_vcpu *host_vcpu,
 	return ret;
 }
 
+static void
+teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size)
+{
+	size = PAGE_ALIGN(size);
+	memset(addr, 0, size);
+
+	for (void *start = addr; start < addr + size; start += PAGE_SIZE)
+		push_hyp_memcache(mc, start, hyp_virt_to_phys);
+
+	unmap_donated_memory_noclear(addr, size);
+}
+
 int __pkvm_teardown_vm(pkvm_handle_t handle)
 {
+	struct kvm_hyp_memcache *mc;
 	struct pkvm_hyp_vm *hyp_vm;
 	unsigned int idx;
 	int err;

@@ -563,7 +576,8 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
 	hyp_spin_unlock(&vm_table_lock);
 
 	/* Reclaim guest pages (including page-table pages) */
-	reclaim_guest_pages(hyp_vm);
+	mc = &hyp_vm->host_kvm->arch.pkvm.teardown_mc;
+	reclaim_guest_pages(hyp_vm, mc);
 	unpin_host_vcpus(hyp_vm->vcpus, hyp_vm->nr_vcpus);
 
 	/* Push the metadata pages to the teardown memcache */

@@ -572,10 +586,10 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
 	for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) {
 		struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx];
 
-		unmap_donated_memory(hyp_vcpu, sizeof(*hyp_vcpu));
+		teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
 	}
 
-	unmap_donated_memory(hyp_vm, hyp_vm->donated_memory_size);
+	teardown_donated_memory(mc, hyp_vm, hyp_vm->donated_memory_size);
 	return 0;
 
 err_unlock:

index 754632a608e3..a9953db08592 100644
@@ -147,8 +147,6 @@ static int __pkvm_create_hyp_vm(struct kvm *host_kvm)
 	handle = ret;
 
 	host_kvm->arch.pkvm.handle = handle;
-	host_kvm->arch.pkvm.hyp_donations.pgd = pgd;
-	host_kvm->arch.pkvm.hyp_donations.vm = hyp_vm;
 
 	/* Donate memory for the vcpus at hyp and initialize it. */
 	hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE);

@@ -167,12 +165,12 @@ static int __pkvm_create_hyp_vm(struct kvm *host_kvm)
 			goto destroy_vm;
 		}
 
-		host_kvm->arch.pkvm.hyp_donations.vcpus[idx] = hyp_vcpu;
-
 		ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu,
 					hyp_vcpu);
-		if (ret)
+		if (ret) {
+			free_pages_exact(hyp_vcpu, hyp_vcpu_sz);
 			goto destroy_vm;
+		}
 	}
 
 	return 0;

@@ -201,30 +199,13 @@ int pkvm_create_hyp_vm(struct kvm *host_kvm)
 
 void pkvm_destroy_hyp_vm(struct kvm *host_kvm)
 {
-	unsigned long idx, nr_vcpus = host_kvm->created_vcpus;
-	size_t pgd_sz, hyp_vm_sz;
-
-	if (host_kvm->arch.pkvm.handle)
+	if (host_kvm->arch.pkvm.handle) {
 		WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm,
 					  host_kvm->arch.pkvm.handle));
-
-	host_kvm->arch.pkvm.handle = 0;
-
-	for (idx = 0; idx < nr_vcpus; ++idx) {
-		void *hyp_vcpu = host_kvm->arch.pkvm.hyp_donations.vcpus[idx];
-
-		if (!hyp_vcpu)
-			break;
-
-		free_pages_exact(hyp_vcpu, PAGE_ALIGN(PKVM_HYP_VCPU_SIZE));
 	}
 
-	hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE,
-					size_mul(sizeof(void *), nr_vcpus)));
-	pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.vtcr);
-
-	free_pages_exact(host_kvm->arch.pkvm.hyp_donations.vm, hyp_vm_sz);
-	free_pages_exact(host_kvm->arch.pkvm.hyp_donations.pgd, pgd_sz);
+	host_kvm->arch.pkvm.handle = 0;
+	free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc);
 }
 
 int pkvm_init_host_vm(struct kvm *host_kvm)

index de52ba775d48..43c3bc0f9544 100644
@@ -109,7 +109,7 @@ enum __kvm_host_smccc_func {
 #define per_cpu_ptr_nvhe_sym(sym, cpu)						\
 	({									\
 		unsigned long base, off;					\
-		base = kvm_arm_hyp_percpu_base[cpu];				\
+		base = kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu];		\
 		off = (unsigned long)&CHOOSE_NVHE_SYM(sym) -			\
 		      (unsigned long)&CHOOSE_NVHE_SYM(__per_cpu_start);		\
 		base ? (typeof(CHOOSE_NVHE_SYM(sym))*)(base + off) : NULL;	\

@@ -214,7 +214,7 @@ DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
 #define __kvm_hyp_init		CHOOSE_NVHE_SYM(__kvm_hyp_init)
 #define __kvm_hyp_vector	CHOOSE_HYP_SYM(__kvm_hyp_vector)
 
-extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
+extern unsigned long kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[];
 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
 

index 7f4e43bfaade..ae8f37f4aa8c 100644
@@ -89,9 +89,6 @@ KVM_NVHE_ALIAS(gic_nonsecure_priorities);
 KVM_NVHE_ALIAS(__start___kvm_ex_table);
 KVM_NVHE_ALIAS(__stop___kvm_ex_table);
 
-/* Array containing bases of nVHE per-CPU memory regions. */
-KVM_NVHE_ALIAS(kvm_arm_hyp_percpu_base);
-
 /* PMU available static key */
 #ifdef CONFIG_HW_PERF_EVENTS
 KVM_NVHE_ALIAS(kvm_arm_pmu_available);

index f78eefa02f6b..25467f24803d 100644
@@ -51,7 +51,6 @@ DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
 DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
 
 DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
-unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
 
 static bool vgic_present;

@@ -1857,13 +1856,13 @@ static void teardown_hyp_mode(void)
 	free_hyp_pgds();
 	for_each_possible_cpu(cpu) {
 		free_page(per_cpu(kvm_arm_hyp_stack_page, cpu));
-		free_pages(kvm_arm_hyp_percpu_base[cpu], nvhe_percpu_order());
+		free_pages(kvm_nvhe_sym(kvm_arm_hyp_percpu_base)[cpu], nvhe_percpu_order());
 	}
 }
 
 static int do_pkvm_init(u32 hyp_va_bits)
 {
-	void *per_cpu_base = kvm_ksym_ref(kvm_arm_hyp_percpu_base);
+	void *per_cpu_base = kvm_ksym_ref(kvm_nvhe_sym(kvm_arm_hyp_percpu_base));
 	int ret;
 
 	preempt_disable();