memory.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2#ifndef __KVM_HYP_MEMORY_H
  3#define __KVM_HYP_MEMORY_H
  4
  5#include <asm/kvm_mmu.h>
  6#include <asm/page.h>
  7
  8#include <linux/types.h>
  9
 10/*
 11 * Bits 0-1 are used to encode the memory ownership state of each page from the
 12 * point of view of a pKVM "component" (host, hyp, guest, ... see enum
 13 * pkvm_component_id):
 14 *   00: The page is owned and exclusively accessible by the component;
 15 *   01: The page is owned and accessible by the component, but is also
 16 *       accessible by another component;
 17 *   10: The page is accessible but not owned by the component;
 18 * The storage of this state depends on the component: either in the
 19 * hyp_vmemmap for the host and hyp states or in PTE software bits for guests.
 20 */
 21enum pkvm_page_state {
 22	PKVM_PAGE_OWNED			= 0ULL,
 23	PKVM_PAGE_SHARED_OWNED		= BIT(0),
 24	PKVM_PAGE_SHARED_BORROWED	= BIT(1),
 25
 26	/*
 27	 * 'Meta-states' are not stored directly in PTE SW bits for guest
 28	 * states, but inferred from the context (e.g. invalid PTE entries).
 29	 * For the host and hyp, meta-states are stored directly in the
 30	 * struct hyp_page.
 31	 */
 32	PKVM_NOPAGE			= BIT(0) | BIT(1),
 33};
 34#define PKVM_PAGE_STATE_MASK		(BIT(0) | BIT(1))
 35
 36#define PKVM_PAGE_STATE_PROT_MASK	(KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)
 37static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,
 38						 enum pkvm_page_state state)
 39{
 40	prot &= ~PKVM_PAGE_STATE_PROT_MASK;
 41	prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state);
 42	return prot;
 43}
 44
 45static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
 46{
 47	return FIELD_GET(PKVM_PAGE_STATE_PROT_MASK, prot);
 48}
 49
 50struct hyp_page {
 51	u16 refcount;
 52	u8 order;
 53
 54	/* Host state. Guarded by the host stage-2 lock. */
 55	unsigned __host_state : 4;
 56
 57	/*
 58	 * Complement of the hyp state. Guarded by the hyp stage-1 lock. We use
 59	 * the complement so that the initial 0 in __hyp_state_comp (due to the
 60	 * entire vmemmap starting off zeroed) encodes PKVM_NOPAGE.
 61	 */
 62	unsigned __hyp_state_comp : 4;
 63
 64	u32 host_share_guest_count;
 65};
 66
 67extern u64 __hyp_vmemmap;
 68#define hyp_vmemmap ((struct hyp_page *)__hyp_vmemmap)
 69
 70#define __hyp_va(phys)	((void *)((phys_addr_t)(phys) - hyp_physvirt_offset))
 71
 72static inline void *hyp_phys_to_virt(phys_addr_t phys)
 73{
 74	return __hyp_va(phys);
 75}
 76
 77static inline phys_addr_t hyp_virt_to_phys(void *addr)
 78{
 79	return __hyp_pa(addr);
 80}
 81
 82#define hyp_phys_to_pfn(phys)	((phys) >> PAGE_SHIFT)
 83#define hyp_pfn_to_phys(pfn)	((phys_addr_t)((pfn) << PAGE_SHIFT))
 84
 85static inline struct hyp_page *hyp_phys_to_page(phys_addr_t phys)
 86{
 87	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u64));
 88	return &hyp_vmemmap[hyp_phys_to_pfn(phys)];
 89}
 90
 91#define hyp_virt_to_page(virt)	hyp_phys_to_page(__hyp_pa(virt))
 92#define hyp_virt_to_pfn(virt)	hyp_phys_to_pfn(__hyp_pa(virt))
 93
 94#define hyp_page_to_pfn(page)	((struct hyp_page *)(page) - hyp_vmemmap)
 95#define hyp_page_to_phys(page)  hyp_pfn_to_phys((hyp_page_to_pfn(page)))
 96#define hyp_page_to_virt(page)	__hyp_va(hyp_page_to_phys(page))
 97#define hyp_page_to_pool(page)	(((struct hyp_page *)page)->pool)
 98
 99static inline enum pkvm_page_state get_host_state(struct hyp_page *p)
100{
101	return p->__host_state;
102}
103
104static inline void set_host_state(struct hyp_page *p, enum pkvm_page_state state)
105{
106	p->__host_state = state;
107}
108
109static inline enum pkvm_page_state get_hyp_state(struct hyp_page *p)
110{
111	return p->__hyp_state_comp ^ PKVM_PAGE_STATE_MASK;
112}
113
114static inline void set_hyp_state(struct hyp_page *p, enum pkvm_page_state state)
115{
116	p->__hyp_state_comp = state ^ PKVM_PAGE_STATE_MASK;
117}
118
119/*
120 * Refcounting for 'struct hyp_page'.
121 * hyp_pool::lock must be held if atomic access to the refcount is required.
122 */
123static inline int hyp_page_count(void *addr)
124{
125	struct hyp_page *p = hyp_virt_to_page(addr);
126
127	return p->refcount;
128}
129
130static inline void hyp_page_ref_inc(struct hyp_page *p)
131{
132	BUG_ON(p->refcount == USHRT_MAX);
133	p->refcount++;
134}
135
136static inline void hyp_page_ref_dec(struct hyp_page *p)
137{
138	BUG_ON(!p->refcount);
139	p->refcount--;
140}
141
142static inline int hyp_page_ref_dec_and_test(struct hyp_page *p)
143{
144	hyp_page_ref_dec(p);
145	return (p->refcount == 0);
146}
147
148static inline void hyp_set_page_refcounted(struct hyp_page *p)
149{
150	BUG_ON(p->refcount);
151	p->refcount = 1;
152}
153#endif /* __KVM_HYP_MEMORY_H */