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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 2/3] xen: implement guest_physmap_(un)pin_range
guest_physmap_pin_range pins a range of guest pages so that they p2m
mappings won't be changed.
guest_physmap_unpin_range unpins the previously pinned pages.
The pinning is done using one of the spare bits in the p2m ptes.
Provide empty stubs for x86.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
xen/arch/arm/p2m.c | 131 ++++++++++++++++++++++++++++++++++++++++++++
xen/include/asm-arm/mm.h | 4 +
xen/include/asm-arm/page.h | 6 ++-
xen/include/asm-x86/p2m.h | 12 ++++
4 files changed, 152 insertions(+), 1 deletions(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 307c6d4..7543ca8 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -75,6 +75,129 @@ done:
return maddr;
}
+
+int guest_physmap_pin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ lpae_t *first = NULL, *second = NULL, *third = NULL, pte;
+ paddr_t addr = gpfn << PAGE_SHIFT;
+ struct p2m_domain *p2m = &d->arch.p2m;
+ int rc = -EFAULT, i;
+ unsigned long cur_first_offset = ~0, cur_second_offset = ~0;
+
+ spin_lock(&p2m->lock);
+
+ first = __map_domain_page(p2m->first_level);
+
+ if ( !first ||
+ !first[first_table_offset(addr)].p2m.valid ||
+ !first[first_table_offset(addr)].p2m.table )
+ goto err;
+
+ for ( i = 0; i < (1UL << order); i++ )
+ {
+ if ( cur_first_offset != first_table_offset(addr) )
+ {
+ if (second) unmap_domain_page(second);
+ second = map_domain_page(first[first_table_offset(addr)].p2m.base);
+ cur_first_offset = first_table_offset(addr);
+ }
+ if ( !second ||
+ !second[second_table_offset(addr)].p2m.valid ||
+ !second[second_table_offset(addr)].p2m.table )
+ goto err;
+
+ if ( cur_second_offset != second_table_offset(addr) )
+ {
+ if (third) unmap_domain_page(third);
+ third =
map_domain_page(second[second_table_offset(addr)].p2m.base);
+ cur_second_offset = second_table_offset(addr);
+ }
+ if ( !third ||
+ !third[third_table_offset(addr)].p2m.valid ||
+ third[third_table_offset(addr)].p2m.avail & P2M_DMA_PIN )
+ goto err;
+
+ pte = third[third_table_offset(addr)];
+ pte.p2m.avail |= P2M_DMA_PIN;
+ write_pte(&third[third_table_offset(addr)], pte);
+
+ addr += PAGE_SIZE;
+ }
+
+ rc = 0;
+
+err:
+ if ( second ) unmap_domain_page(second);
+ if ( first ) unmap_domain_page(first);
+
+ spin_unlock(&p2m->lock);
+
+ return rc;
+}
+
+int guest_physmap_unpin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ lpae_t *first = NULL, *second = NULL, *third = NULL, pte;
+ paddr_t addr = gpfn << PAGE_SHIFT;
+ struct p2m_domain *p2m = &d->arch.p2m;
+ int rc = -EFAULT, i;
+ unsigned long cur_first_offset = ~0, cur_second_offset = ~0;
+
+ spin_lock(&p2m->lock);
+
+ first = __map_domain_page(p2m->first_level);
+
+ if ( !first ||
+ !first[first_table_offset(addr)].p2m.valid ||
+ !first[first_table_offset(addr)].p2m.table )
+ goto err;
+
+ for ( i = 0; i < (1UL << order); i++ )
+ {
+ if ( cur_first_offset != first_table_offset(addr) )
+ {
+ if (second) unmap_domain_page(second);
+ second = map_domain_page(first[first_table_offset(addr)].p2m.base);
+ cur_first_offset = first_table_offset(addr);
+ }
+ if ( !second ||
+ !second[second_table_offset(addr)].p2m.valid ||
+ !second[second_table_offset(addr)].p2m.table )
+ goto err;
+
+ if ( cur_second_offset != second_table_offset(addr) )
+ {
+ if (third) unmap_domain_page(third);
+ third =
map_domain_page(second[second_table_offset(addr)].p2m.base);
+ cur_second_offset = second_table_offset(addr);
+ }
+ if ( !third ||
+ !third[third_table_offset(addr)].p2m.valid ||
+ !(third[third_table_offset(addr)].p2m.avail & P2M_DMA_PIN) )
+ goto err;
+
+ pte = third[third_table_offset(addr)];
+ pte.p2m.avail &= ~P2M_DMA_PIN;
+ write_pte(&third[third_table_offset(addr)], pte);
+
+ addr += PAGE_SIZE;
+ }
+
+ rc = 0;
+
+err:
+ if ( second ) unmap_domain_page(second);
+ if ( first ) unmap_domain_page(first);
+
+ spin_unlock(&p2m->lock);
+
+ return rc;
+}
+
int guest_physmap_mark_populate_on_demand(struct domain *d,
unsigned long gfn,
unsigned int order)
@@ -184,6 +307,14 @@ static int create_p2m_entries(struct domain *d,
cur_second_offset = second_table_offset(addr);
}
+ if ( third[third_table_offset(addr)].p2m.avail & P2M_DMA_PIN )
+ {
+ rc = -EINVAL;
+ printk("%s: cannot change p2m mapping for paddr=%"PRIpaddr
+ " domid=%d, the page is pinned\n", __func__, addr,
d->domain_id);
+ goto out;
+ }
+
flush = third[third_table_offset(addr)].p2m.valid;
/* Allocate a new RAM page and attach */
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 5e7c5a3..8db8816 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -319,6 +319,10 @@ void free_init_memory(void);
int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn,
unsigned int order);
+int guest_physmap_pin_range(struct domain *d, xen_pfn_t gpfn,
+ unsigned int order);
+int guest_physmap_unpin_range(struct domain *d, xen_pfn_t gpfn,
+ unsigned int order);
extern void put_page_type(struct page_info *page);
static inline void put_page_and_type(struct page_info *page)
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 41e9eff..12087d0 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -153,11 +153,15 @@ typedef struct {
unsigned long hint:1; /* In a block of 16 contiguous entries */
unsigned long sbz2:1;
unsigned long xn:1; /* eXecute-Never */
- unsigned long avail:4; /* Ignored by hardware */
+ unsigned long avail:4; /* Ignored by hardware, see below */
unsigned long sbz1:5;
} __attribute__((__packed__)) lpae_p2m_t;
+/* Xen "avail" bits allocation in third level entries */
+#define P2M_DMA_PIN (1<<0) /* The page has been "pinned": the hypervisor
+ promises not to change the p2m mapping. */
+
/*
* Walk is the common bits of p2m and pt entries which are needed to
* simply walk the table (e.g. for debug).
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 43583b2..afc7738 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -492,6 +492,18 @@ void guest_physmap_remove_page(struct domain *d,
/* Set a p2m range as populate-on-demand */
int guest_physmap_mark_populate_on_demand(struct domain *d, unsigned long gfn,
unsigned int order);
+static inline int guest_physmap_pin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ return -ENOSYS;
+}
+int guest_physmap_unpin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ return -ENOSYS;
+}
/* Change types across all p2m entries in a domain */
void p2m_change_entry_type_global(struct domain *d,
--
1.7.2.5
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