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KVM: arm64: Factor memory allocation out of pgtable.c 

In preparation for enabling the creation of page-tables at EL2, factor
all memory allocation out of the page-table code, hence making it
re-usable with any compatible memory allocator.

No functional changes intended.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-7-qperret@google.com
This commit is contained in:
Quentin Perret 2021-03-19 10:01:14 +00:00 committed by Marc Zyngier
parent cc706a6389
commit 7aef0cbcdc
3 changed files with 163 additions and 42 deletions
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41
arch/arm64/include/asm/kvm_pgtable.h
View File

@ -13,17 +13,50 @@
typedef u64 kvm_pte_t;
/**
* struct kvm_pgtable_mm_ops - Memory management callbacks.
* @zalloc_page: Allocate a single zeroed memory page. The @arg parameter
* can be used by the walker to pass a memcache. The
* initial refcount of the page is 1.
* @zalloc_pages_exact: Allocate an exact number of zeroed memory pages. The
* @size parameter is in bytes, and is rounded-up to the
* next page boundary. The resulting allocation is
* physically contiguous.
* @free_pages_exact: Free an exact number of memory pages previously
* allocated by zalloc_pages_exact.
* @get_page: Increment the refcount on a page.
* @put_page: Decrement the refcount on a page. When the refcount
* reaches 0 the page is automatically freed.
* @page_count: Return the refcount of a page.
* @phys_to_virt: Convert a physical address into a virtual address mapped
* in the current context.
* @virt_to_phys: Convert a virtual address mapped in the current context
* into a physical address.
*/
struct kvm_pgtable_mm_ops {
void* (*zalloc_page)(void *arg);
void* (*zalloc_pages_exact)(size_t size);
void (*free_pages_exact)(void *addr, size_t size);
void (*get_page)(void *addr);
void (*put_page)(void *addr);
int (*page_count)(void *addr);
void* (*phys_to_virt)(phys_addr_t phys);
phys_addr_t (*virt_to_phys)(void *addr);
};
/**
* struct kvm_pgtable - KVM page-table.
* @ia_bits: Maximum input address size, in bits.
* @start_level: Level at which the page-table walk starts.
* @pgd: Pointer to the first top-level entry of the page-table.
* @mm_ops: Memory management callbacks.
* @mmu: Stage-2 KVM MMU struct. Unused for stage-1 page-tables.
*/
struct kvm_pgtable {
u32 ia_bits;
u32 start_level;
kvm_pte_t *pgd;
struct kvm_pgtable_mm_ops *mm_ops;
/* Stage-2 only */
struct kvm_s2_mmu *mmu;
@ -86,10 +119,12 @@ struct kvm_pgtable_walker {
* kvm_pgtable_hyp_init() - Initialise a hypervisor stage-1 page-table.
* @pgt: Uninitialised page-table structure to initialise.
* @va_bits: Maximum virtual address bits.
* @mm_ops: Memory management callbacks.
*
* Return: 0 on success, negative error code on failure.
*/
int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits);
int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
struct kvm_pgtable_mm_ops *mm_ops);
/**
* kvm_pgtable_hyp_destroy() - Destroy an unused hypervisor stage-1 page-table.
@ -126,10 +161,12 @@ int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
* kvm_pgtable_stage2_init() - Initialise a guest stage-2 page-table.
* @pgt: Uninitialised page-table structure to initialise.
* @kvm: KVM structure representing the guest virtual machine.
* @mm_ops: Memory management callbacks.
*
* Return: 0 on success, negative error code on failure.
*/
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm *kvm);
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm *kvm,
struct kvm_pgtable_mm_ops *mm_ops);
/**
* kvm_pgtable_stage2_destroy() - Destroy an unused guest stage-2 page-table.

98
arch/arm64/kvm/hyp/pgtable.c
View File

@ -152,9 +152,9 @@ static kvm_pte_t kvm_phys_to_pte(u64 pa)
return pte;
}
static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte)
static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops)
{
return __va(kvm_pte_to_phys(pte));
return mm_ops->phys_to_virt(kvm_pte_to_phys(pte));
}
static void kvm_set_invalid_pte(kvm_pte_t *ptep)
@ -163,9 +163,10 @@ static void kvm_set_invalid_pte(kvm_pte_t *ptep)
WRITE_ONCE(*ptep, pte & ~KVM_PTE_VALID);
}
static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp)
static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp,
struct kvm_pgtable_mm_ops *mm_ops)
{
kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(__pa(childp));
kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE);
pte |= KVM_PTE_VALID;
@ -228,7 +229,7 @@ static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
goto out;
}
childp = kvm_pte_follow(pte);
childp = kvm_pte_follow(pte, data->pgt->mm_ops);
ret = __kvm_pgtable_walk(data, childp, level + 1);
if (ret)
goto out;
@ -303,8 +304,9 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
}
struct hyp_map_data {
u64 phys;
kvm_pte_t attr;
u64 phys;
kvm_pte_t attr;
struct kvm_pgtable_mm_ops *mm_ops;
};
static int hyp_map_set_prot_attr(enum kvm_pgtable_prot prot,
@ -359,6 +361,8 @@ static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag, void * const arg)
{
kvm_pte_t *childp;
struct hyp_map_data *data = arg;
struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
if (hyp_map_walker_try_leaf(addr, end, level, ptep, arg))
return 0;
@ -366,11 +370,11 @@ static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1))
return -EINVAL;
childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL);
childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
if (!childp)
return -ENOMEM;
kvm_set_table_pte(ptep, childp);
kvm_set_table_pte(ptep, childp, mm_ops);
return 0;
}
@ -380,6 +384,7 @@ int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
int ret;
struct hyp_map_data map_data = {
.phys = ALIGN_DOWN(phys, PAGE_SIZE),
.mm_ops = pgt->mm_ops,
};
struct kvm_pgtable_walker walker = {
.cb = hyp_map_walker,
@ -397,16 +402,18 @@ int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
return ret;
}
int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits)
int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
struct kvm_pgtable_mm_ops *mm_ops)
{
u64 levels = ARM64_HW_PGTABLE_LEVELS(va_bits);
pgt->pgd = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL);
pgt->pgd = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
if (!pgt->pgd)
return -ENOMEM;
pgt->ia_bits = va_bits;
pgt->start_level = KVM_PGTABLE_MAX_LEVELS - levels;
pgt->mm_ops = mm_ops;
pgt->mmu = NULL;
return 0;
}
@ -414,7 +421,9 @@ int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits)
static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag, void * const arg)
{
put_page(virt_to_page(kvm_pte_follow(*ptep)));
struct kvm_pgtable_mm_ops *mm_ops = arg;
mm_ops->put_page((void *)kvm_pte_follow(*ptep, mm_ops));
return 0;
}
@ -423,10 +432,11 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
struct kvm_pgtable_walker walker = {
.cb = hyp_free_walker,
.flags = KVM_PGTABLE_WALK_TABLE_POST,
.arg = pgt->mm_ops,
};
WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
put_page(virt_to_page(pgt->pgd));
pgt->mm_ops->put_page(pgt->pgd);
pgt->pgd = NULL;
}
@ -438,6 +448,8 @@ struct stage2_map_data {
struct kvm_s2_mmu *mmu;
struct kvm_mmu_memory_cache *memcache;
struct kvm_pgtable_mm_ops *mm_ops;
};
static int stage2_map_set_prot_attr(enum kvm_pgtable_prot prot,
@ -471,7 +483,7 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
{
kvm_pte_t new, old = *ptep;
u64 granule = kvm_granule_size(level), phys = data->phys;
struct page *page = virt_to_page(ptep);
struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
if (!kvm_block_mapping_supported(addr, end, phys, level))
return -E2BIG;
@ -493,11 +505,11 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
*/
kvm_set_invalid_pte(ptep);
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, data->mmu, addr, level);
put_page(page);
mm_ops->put_page(ptep);
}
smp_store_release(ptep, new);
get_page(page);
mm_ops->get_page(ptep);
data->phys += granule;
return 0;
}
@ -527,13 +539,13 @@ static int stage2_map_walk_table_pre(u64 addr, u64 end, u32 level,
static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
struct stage2_map_data *data)
{
int ret;
struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
kvm_pte_t *childp, pte = *ptep;
struct page *page = virt_to_page(ptep);
int ret;
if (data->anchor) {
if (kvm_pte_valid(pte))
put_page(page);
mm_ops->put_page(ptep);
return 0;
}
@ -548,7 +560,7 @@ static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (!data->memcache)
return -ENOMEM;
childp = kvm_mmu_memory_cache_alloc(data->memcache);
childp = mm_ops->zalloc_page(data->memcache);
if (!childp)
return -ENOMEM;
@ -560,11 +572,11 @@ static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
if (kvm_pte_valid(pte)) {
kvm_set_invalid_pte(ptep);
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, data->mmu, addr, level);
put_page(page);
mm_ops->put_page(ptep);
}
kvm_set_table_pte(ptep, childp);
get_page(page);
kvm_set_table_pte(ptep, childp, mm_ops);
mm_ops->get_page(ptep);
return 0;
}
@ -573,13 +585,14 @@ static int stage2_map_walk_table_post(u64 addr, u64 end, u32 level,
kvm_pte_t *ptep,
struct stage2_map_data *data)
{
struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
int ret = 0;
if (!data->anchor)
return 0;
put_page(virt_to_page(kvm_pte_follow(*ptep)));
put_page(virt_to_page(ptep));
mm_ops->put_page(kvm_pte_follow(*ptep, mm_ops));
mm_ops->put_page(ptep);
if (data->anchor == ptep) {
data->anchor = NULL;
@ -634,6 +647,7 @@ int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
.phys = ALIGN_DOWN(phys, PAGE_SIZE),
.mmu = pgt->mmu,
.memcache = mc,
.mm_ops = pgt->mm_ops,
};
struct kvm_pgtable_walker walker = {
.cb = stage2_map_walker,
@ -670,7 +684,9 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
enum kvm_pgtable_walk_flags flag,
void * const arg)
{
struct kvm_s2_mmu *mmu = arg;
struct kvm_pgtable *pgt = arg;
struct kvm_s2_mmu *mmu = pgt->mmu;
struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
kvm_pte_t pte = *ptep, *childp = NULL;
bool need_flush = false;
@ -678,9 +694,9 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
return 0;
if (kvm_pte_table(pte, level)) {
childp = kvm_pte_follow(pte);
childp = kvm_pte_follow(pte, mm_ops);
if (page_count(virt_to_page(childp)) != 1)
if (mm_ops->page_count(childp) != 1)
return 0;
} else if (stage2_pte_cacheable(pte)) {
need_flush = true;
@ -693,15 +709,15 @@ static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
*/
kvm_set_invalid_pte(ptep);
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, addr, level);
put_page(virt_to_page(ptep));
mm_ops->put_page(ptep);
if (need_flush) {
stage2_flush_dcache(kvm_pte_follow(pte),
stage2_flush_dcache(kvm_pte_follow(pte, mm_ops),
kvm_granule_size(level));
}
if (childp)
put_page(virt_to_page(childp));
mm_ops->put_page(childp);
return 0;
}
@ -710,7 +726,7 @@ int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
{
struct kvm_pgtable_walker walker = {
.cb = stage2_unmap_walker,
.arg = pgt->mmu,
.arg = pgt,
.flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
};
@ -842,12 +858,13 @@ static int stage2_flush_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;
if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pte))
return 0;
stage2_flush_dcache(kvm_pte_follow(pte), kvm_granule_size(level));
stage2_flush_dcache(kvm_pte_follow(pte, mm_ops), kvm_granule_size(level));
return 0;
}
@ -856,6 +873,7 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
struct kvm_pgtable_walker walker = {
.cb = stage2_flush_walker,
.flags = KVM_PGTABLE_WALK_LEAF,
.arg = pgt->mm_ops,
};
if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
@ -864,7 +882,8 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
return kvm_pgtable_walk(pgt, addr, size, &walker);
}
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm *kvm)
int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm *kvm,
struct kvm_pgtable_mm_ops *mm_ops)
{
size_t pgd_sz;
u64 vtcr = kvm->arch.vtcr;
@ -873,12 +892,13 @@ int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm *kvm)
u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
pgt->pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
pgt->pgd = mm_ops->zalloc_pages_exact(pgd_sz);
if (!pgt->pgd)
return -ENOMEM;
pgt->ia_bits = ia_bits;
pgt->start_level = start_level;
pgt->mm_ops = mm_ops;
pgt->mmu = &kvm->arch.mmu;
/* Ensure zeroed PGD pages are visible to the hardware walker */
@ -890,15 +910,16 @@ static int stage2_free_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;
if (!kvm_pte_valid(pte))
return 0;
put_page(virt_to_page(ptep));
mm_ops->put_page(ptep);
if (kvm_pte_table(pte, level))
put_page(virt_to_page(kvm_pte_follow(pte)));
mm_ops->put_page(kvm_pte_follow(pte, mm_ops));
return 0;
}
@ -910,10 +931,11 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
.cb = stage2_free_walker,
.flags = KVM_PGTABLE_WALK_LEAF |
KVM_PGTABLE_WALK_TABLE_POST,
.arg = pgt->mm_ops,
};
WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
free_pages_exact(pgt->pgd, pgd_sz);
pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz);
pgt->pgd = NULL;
}

66
arch/arm64/kvm/mmu.c
View File

@ -88,6 +88,44 @@ static bool kvm_is_device_pfn(unsigned long pfn)
return !pfn_valid(pfn);
}
static void *stage2_memcache_zalloc_page(void *arg)
{
struct kvm_mmu_memory_cache *mc = arg;
/* Allocated with __GFP_ZERO, so no need to zero */
return kvm_mmu_memory_cache_alloc(mc);
}
static void *kvm_host_zalloc_pages_exact(size_t size)
{
return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
}
static void kvm_host_get_page(void *addr)
{
get_page(virt_to_page(addr));
}
static void kvm_host_put_page(void *addr)
{
put_page(virt_to_page(addr));
}
static int kvm_host_page_count(void *addr)
{
return page_count(virt_to_page(addr));
}
static phys_addr_t kvm_host_pa(void *addr)
{
return __pa(addr);
}
static void *kvm_host_va(phys_addr_t phys)
{
return __va(phys);
}
/*
* Unmapping vs dcache management:
*
@ -351,6 +389,17 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
return 0;
}
static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
.zalloc_page = stage2_memcache_zalloc_page,
.zalloc_pages_exact = kvm_host_zalloc_pages_exact,
.free_pages_exact = free_pages_exact,
.get_page = kvm_host_get_page,
.put_page = kvm_host_put_page,
.page_count = kvm_host_page_count,
.phys_to_virt = kvm_host_va,
.virt_to_phys = kvm_host_pa,
};
/**
* kvm_init_stage2_mmu - Initialise a S2 MMU strucrure
* @kvm: The pointer to the KVM structure
@ -374,7 +423,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
if (!pgt)
return -ENOMEM;
err = kvm_pgtable_stage2_init(pgt, kvm);
err = kvm_pgtable_stage2_init(pgt, kvm, &kvm_s2_mm_ops);
if (err)
goto out_free_pgtable;
@ -1208,6 +1257,19 @@ static int kvm_map_idmap_text(void)
return err;
}
static void *kvm_hyp_zalloc_page(void *arg)
{
return (void *)get_zeroed_page(GFP_KERNEL);
}
static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = {
.zalloc_page = kvm_hyp_zalloc_page,
.get_page = kvm_host_get_page,
.put_page = kvm_host_put_page,
.phys_to_virt = kvm_host_va,
.virt_to_phys = kvm_host_pa,
};
int kvm_mmu_init(void)
{
int err;
@ -1251,7 +1313,7 @@ int kvm_mmu_init(void)
goto out;
}
err = kvm_pgtable_hyp_init(hyp_pgtable, hyp_va_bits);
err = kvm_pgtable_hyp_init(hyp_pgtable, hyp_va_bits, &kvm_hyp_mm_ops);
if (err)
goto out_free_pgtable;