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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [for-4.8][PATCH v2 21/23] xen/arm: p2m: Re-implement p2m_set_mem_access using p2m_{set, get}_entry
The function p2m_set_mem_access can be re-implemented using the generic
functions p2m_get_entry and __p2m_set_entry.
Also the function apply_p2m_changes is dropped completely as it is not
used anymore.
Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
Cc: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
Changes in v2:
- Remove level_shifts as it is not used anymore
- Fix multiple bugs in the code
- Use gfn_next_boundary
- Drop the paragraph about performance issue as
Break-Before-Make is not required when only the permission are
changed.
---
xen/arch/arm/p2m.c | 327 +++++------------------------------------------------
1 file changed, 29 insertions(+), 298 deletions(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 734923b..aa740c2 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -34,8 +34,6 @@ static const paddr_t level_sizes[] =
{ ZEROETH_SIZE, FIRST_SIZE, SECOND_SIZE, THIRD_SIZE };
static const paddr_t level_masks[] =
{ ZEROETH_MASK, FIRST_MASK, SECOND_MASK, THIRD_MASK };
-static const uint8_t level_shifts[] =
- { ZEROETH_SHIFT, FIRST_SHIFT, SECOND_SHIFT, THIRD_SHIFT };
static const uint8_t level_orders[] =
{ ZEROETH_ORDER, FIRST_ORDER, SECOND_ORDER, THIRD_ORDER };
@@ -1154,295 +1152,6 @@ int p2m_set_entry(struct p2m_domain *p2m,
return rc;
}
-#define P2M_ONE_DESCEND 0
-#define P2M_ONE_PROGRESS_NOP 0x1
-#define P2M_ONE_PROGRESS 0x10
-
-static int p2m_shatter_page(struct p2m_domain *p2m,
- lpae_t *entry,
- unsigned int level)
-{
- const uint8_t level_shift = level_shifts[level];
- int rc = p2m_create_table(p2m, entry, level_shift - PAGE_SHIFT);
-
- if ( !rc )
- {
- p2m->stats.shattered[level]++;
- p2m->stats.mappings[level]--;
- p2m->stats.mappings[level+1] += LPAE_ENTRIES;
- }
-
- return rc;
-}
-
-/*
- * 0 == (P2M_ONE_DESCEND) continue to descend the tree
- * +ve == (P2M_ONE_PROGRESS_*) handled at this level, continue, flush,
- * entry, addr and maddr updated. Return value is an
- * indication of the amount of work done (for preemption).
- * -ve == (-Exxx) error.
- */
-static int apply_one_level(struct domain *d,
- lpae_t *entry,
- unsigned int level,
- enum p2m_operation op,
- paddr_t start_gpaddr,
- paddr_t end_gpaddr,
- paddr_t *addr,
- paddr_t *maddr,
- bool_t *flush,
- p2m_type_t t,
- p2m_access_t a)
-{
- const paddr_t level_size = level_sizes[level];
-
- struct p2m_domain *p2m = &d->arch.p2m;
- lpae_t pte;
- const lpae_t orig_pte = *entry;
- int rc;
-
- BUG_ON(level > 3);
-
- switch ( op )
- {
- case MEMACCESS:
- if ( level < 3 )
- {
- if ( !p2m_valid(orig_pte) )
- {
- *addr += level_size;
- return P2M_ONE_PROGRESS_NOP;
- }
-
- /* Shatter large pages as we descend */
- if ( p2m_mapping(orig_pte) )
- {
- rc = p2m_shatter_page(p2m, entry, level);
- if ( rc < 0 )
- return rc;
- } /* else: an existing table mapping -> descend */
-
- return P2M_ONE_DESCEND;
- }
- else
- {
- pte = orig_pte;
-
- if ( p2m_valid(pte) )
- {
- rc = p2m_mem_access_radix_set(p2m, _gfn(paddr_to_pfn(*addr)),
- a);
- if ( rc < 0 )
- return rc;
-
- p2m_set_permission(&pte, pte.p2m.type, a);
- p2m_write_pte(entry, pte, p2m->clean_pte);
- }
-
- *addr += level_size;
- *flush = true;
- return P2M_ONE_PROGRESS;
- }
- }
-
- BUG(); /* Should never get here */
-}
-
-/*
- * The page is only used by the P2M code which is protected by the p2m->lock.
- * So we can avoid to use atomic helpers.
- */
-static void update_reference_mapping(struct page_info *page,
- lpae_t old_entry,
- lpae_t new_entry)
-{
- if ( p2m_valid(old_entry) && !p2m_valid(new_entry) )
- page->u.inuse.p2m_refcount--;
- else if ( !p2m_valid(old_entry) && p2m_valid(new_entry) )
- page->u.inuse.p2m_refcount++;
-}
-
-static int apply_p2m_changes(struct domain *d,
- enum p2m_operation op,
- gfn_t sgfn,
- unsigned long nr,
- mfn_t smfn,
- uint32_t mask,
- p2m_type_t t,
- p2m_access_t a)
-{
- paddr_t start_gpaddr = pfn_to_paddr(gfn_x(sgfn));
- paddr_t end_gpaddr = pfn_to_paddr(gfn_x(sgfn) + nr);
- paddr_t maddr = pfn_to_paddr(mfn_x(smfn));
- int rc, ret;
- struct p2m_domain *p2m = &d->arch.p2m;
- lpae_t *mappings[4] = { NULL, NULL, NULL, NULL };
- struct page_info *pages[4] = { NULL, NULL, NULL, NULL };
- paddr_t addr;
- unsigned int level = 0;
- unsigned int cur_root_table = ~0;
- unsigned int cur_offset[4] = { ~0, ~0, ~0, ~0 };
- unsigned int count = 0;
- const unsigned int preempt_count_limit = (op == MEMACCESS) ? 1 : 0x2000;
- const bool_t preempt = !is_idle_vcpu(current);
- bool_t flush = false;
- PAGE_LIST_HEAD(free_pages);
- struct page_info *pg;
-
- p2m_write_lock(p2m);
-
- /* Static mapping. P2M_ROOT_PAGES > 1 are handled below */
- if ( P2M_ROOT_PAGES == 1 )
- {
- mappings[P2M_ROOT_LEVEL] = __map_domain_page(p2m->root);
- pages[P2M_ROOT_LEVEL] = p2m->root;
- }
-
- addr = start_gpaddr;
- while ( addr < end_gpaddr )
- {
- int root_table;
- const unsigned int offsets[4] = {
- zeroeth_table_offset(addr),
- first_table_offset(addr),
- second_table_offset(addr),
- third_table_offset(addr)
- };
-
- /*
- * Check if current iteration should be possibly preempted.
- * Since count is initialised to 0 above we are guaranteed to
- * always make at least one pass as long as preempt_count_limit is
- * initialized with a value >= 1.
- */
- if ( preempt && count >= preempt_count_limit
- && hypercall_preempt_check() )
- {
- switch ( op )
- {
- case MEMACCESS:
- {
- /*
- * Preempt setting mem_access permissions as required by
XSA-89,
- * if it's not the last iteration.
- */
- uint32_t progress = paddr_to_pfn(addr) - gfn_x(sgfn) + 1;
-
- if ( nr > progress && !(progress & mask) )
- {
- rc = progress;
- goto out;
- }
- break;
- }
-
- default:
- break;
- };
-
- /*
- * Reset current iteration counter.
- */
- count = 0;
- }
-
- if ( P2M_ROOT_PAGES > 1 )
- {
- int i;
- /*
- * Concatenated root-level tables. The table number will be the
- * offset at the previous level. It is not possible to concatenate
- * a level-0 root.
- */
- ASSERT(P2M_ROOT_LEVEL > 0);
- root_table = offsets[P2M_ROOT_LEVEL - 1];
- if ( root_table >= P2M_ROOT_PAGES )
- {
- rc = -EINVAL;
- goto out;
- }
-
- if ( cur_root_table != root_table )
- {
- if ( mappings[P2M_ROOT_LEVEL] )
- unmap_domain_page(mappings[P2M_ROOT_LEVEL]);
- mappings[P2M_ROOT_LEVEL] =
- __map_domain_page(p2m->root + root_table);
- pages[P2M_ROOT_LEVEL] = p2m->root + root_table;
- cur_root_table = root_table;
- /* Any mapping further down is now invalid */
- for ( i = P2M_ROOT_LEVEL; i < 4; i++ )
- cur_offset[i] = ~0;
- }
- }
-
- for ( level = P2M_ROOT_LEVEL; level < 4; level++ )
- {
- unsigned offset = offsets[level];
- lpae_t *entry = &mappings[level][offset];
- lpae_t old_entry = *entry;
-
- ret = apply_one_level(d, entry,
- level, op,
- start_gpaddr, end_gpaddr,
- &addr, &maddr, &flush,
- t, a);
- if ( ret < 0 ) { rc = ret ; goto out; }
- count += ret;
-
- if ( ret != P2M_ONE_PROGRESS_NOP )
- update_reference_mapping(pages[level], old_entry, *entry);
-
- /* L3 had better have done something! We cannot descend any
further */
- BUG_ON(level == 3 && ret == P2M_ONE_DESCEND);
- if ( ret != P2M_ONE_DESCEND ) break;
-
- BUG_ON(!p2m_valid(*entry));
-
- if ( cur_offset[level] != offset )
- {
- /* Update mapping for next level */
- int i;
- if ( mappings[level+1] )
- unmap_domain_page(mappings[level+1]);
- mappings[level+1] = map_domain_page(_mfn(entry->p2m.base));
- pages[level+1] = mfn_to_page(entry->p2m.base);
- cur_offset[level] = offset;
- /* Any mapping further down is now invalid */
- for ( i = level+1; i < 4; i++ )
- cur_offset[i] = ~0;
- }
- /* else: next level already valid */
- }
-
- BUG_ON(level > 3);
- }
-
- rc = 0;
-
-out:
- if ( flush )
- {
- p2m_flush_tlb_sync(&d->arch.p2m);
- ret = iommu_iotlb_flush(d, gfn_x(sgfn), nr);
- if ( !rc )
- rc = ret;
- }
-
- while ( (pg = page_list_remove_head(&free_pages)) )
- free_domheap_page(pg);
-
- for ( level = P2M_ROOT_LEVEL; level < 4; level ++ )
- {
- if ( mappings[level] )
- unmap_domain_page(mappings[level]);
- }
-
- p2m_write_unlock(p2m);
-
- return rc;
-}
-
static inline int p2m_insert_mapping(struct domain *d,
gfn_t start_gfn,
unsigned long nr,
@@ -2139,6 +1848,7 @@ long p2m_set_mem_access(struct domain *d, gfn_t gfn,
uint32_t nr,
{
struct p2m_domain *p2m = p2m_get_hostp2m(d);
p2m_access_t a;
+ unsigned int order;
long rc = 0;
static const p2m_access_t memaccess[] = {
@@ -2181,14 +1891,35 @@ long p2m_set_mem_access(struct domain *d, gfn_t gfn,
uint32_t nr,
return 0;
}
- rc = apply_p2m_changes(d, MEMACCESS, gfn_add(gfn, start),
- (nr - start), INVALID_MFN, mask, 0, a);
- if ( rc < 0 )
- return rc;
- else if ( rc > 0 )
- return start + rc;
+ p2m_write_lock(p2m);
- return 0;
+ for ( gfn = gfn_add(gfn, start); nr > start;
+ gfn = gfn_next_boundary(gfn, order) )
+ {
+ p2m_type_t t;
+ mfn_t mfn = p2m_get_entry(p2m, gfn, &t, NULL, &order);
+
+
+ if ( !mfn_eq(mfn, INVALID_MFN) )
+ {
+ order = 0;
+ rc = __p2m_set_entry(p2m, gfn, 0, mfn, t, a);
+ if ( rc )
+ break;
+ }
+
+ start += gfn_x(gfn_next_boundary(gfn, order)) - gfn_x(gfn);
+ /* Check for continuation if it is not the last iteration */
+ if ( nr > start && !(start & mask) && hypercall_preempt_check() )
+ {
+ rc = start;
+ break;
+ }
+ }
+
+ p2m_write_unlock(p2m);
+
+ return rc;
}
int p2m_get_mem_access(struct domain *d, gfn_t gfn,
--
1.9.1
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