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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v6 3/5] xen: implement guest_physmap_pin_range and guest_physmap_unpin_range
guest_physmap_pin_range pins a range of guest pages so that their p2m
mappings won't be changed.
guest_physmap_unpin_range unpins the previously pinned pages.
The pinning is done using a new count_info flag.
Provide empty stubs for x86.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Changes in v6:
- guest_physmap_pin_range: check that the pages are normal r/w ram pages;
- guest_physmap_unpin_range: return -EINVAL instead of -EBUSY if a page
is not pinned;
- use a count_info flag rather than using spare bits in the ptes.
Changes in v5:
- return -EBUSY when the P2M_DMA_PIN check fails;
- rename _guest_physmap_pin_range to pin_one_pte;
- rename _guest_physmap_unpin_range to unpin_one_pte.
Changes in v4:
- use p2m_walker to implement guest_physmap_pin_range and
guest_physmap_unpin_range;
- return -EINVAL when the P2M_DMA_PIN check fails;
- change the printk into a gdprintk;
- add a comment on what type of page can be pinned.
---
xen/arch/arm/p2m.c | 57 ++++++++++++++++++++++++++++++++++++++++++++-
xen/include/asm-arm/mm.h | 7 +++++
xen/include/asm-x86/p2m.h | 12 +++++++++
3 files changed, 75 insertions(+), 1 deletions(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 05048c2..ff32b5a 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -157,6 +157,49 @@ paddr_t p2m_lookup(struct domain *d, paddr_t paddr)
return p2m.maddr;
}
+int guest_physmap_pin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ int i;
+ struct page_info *page;
+ xen_pfn_t mfn;
+
+ for ( i = 0; i < (1UL << order); i++ )
+ {
+ mfn = gmfn_to_mfn(d, gpfn + i);
+ page = mfn_to_page(mfn);
+ if ( !page )
+ return -EINVAL;
+ if ( is_iomem_page(mfn) ||
+ !get_page_type(page, PGT_writable_page) )
+ return -EINVAL;
+ if ( test_and_set_bit(_PGC_p2m_pinned, &page->count_info) )
+ return -EBUSY;
+ }
+ return 0;
+}
+
+int guest_physmap_unpin_range(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ int i;
+ struct page_info *page;
+ xen_pfn_t mfn;
+
+ for ( i = 0; i < (1UL << order); i++ )
+ {
+ mfn = gmfn_to_mfn(d, gpfn + i);
+ page = mfn_to_page(mfn);
+ if ( !page )
+ return -EINVAL;
+ if ( !test_and_clear_bit(_PGC_p2m_pinned, &page->count_info) )
+ return -EINVAL;
+ }
+ return 0;
+}
+
int guest_physmap_mark_populate_on_demand(struct domain *d,
unsigned long gfn,
unsigned int order)
@@ -217,6 +260,7 @@ static int create_p2m_entries(struct domain *d,
lpae_t *first = NULL, *second = NULL, *third = NULL;
paddr_t addr;
unsigned long cur_first_offset = ~0, cur_second_offset = ~0;
+ struct page_info *page;
spin_lock(&p2m->lock);
@@ -228,6 +272,8 @@ static int create_p2m_entries(struct domain *d,
for(addr = start_gpaddr; addr < end_gpaddr; addr += PAGE_SIZE)
{
+ page = NULL;
+
if ( !first[first_table_offset(addr)].p2m.valid )
{
rc = p2m_create_table(d, &first[first_table_offset(addr)]);
@@ -268,11 +314,20 @@ static int create_p2m_entries(struct domain *d,
flush = third[third_table_offset(addr)].p2m.valid;
+ if ( flush )
+ page = mfn_to_page(third[third_table_offset(addr)].p2m.base);
+ if ( page && test_bit(_PGC_p2m_pinned, &page->count_info) )
+ {
+ rc = -EINVAL;
+ gdprintk(XENLOG_WARNING, "cannot change p2m mapping for
paddr=%"PRIpaddr
+ " domid=%d, the page is pinned\n", addr, d->domain_id);
+ goto out;
+ }
+
/* Allocate a new RAM page and attach */
switch (op) {
case ALLOCATE:
{
- struct page_info *page;
lpae_t pte;
rc = -ENOMEM;
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index b7a9871..06b5aad 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -99,6 +99,9 @@ struct page_info
/* Page is Xen heap? */
#define _PGC_xen_heap PG_shift(2)
#define PGC_xen_heap PG_mask(1, 2)
+/* The page belong to a guest and it has been pinned. */
+#define _PGC_p2m_pinned PG_shift(3)
+#define PGC_p2m_pinned PG_mask(1, 3)
/* ... */
/* Page is broken? */
#define _PGC_broken PG_shift(7)
@@ -335,6 +338,10 @@ 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-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 43583b2..b08a722 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;
+}
+static inline 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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