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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [V16 PATCH 1/3] pvh dom0: Add and remove foreign pages
In this patch, a new function, p2m_add_foreign(), is added
to map pages from a foreign guest into dom0 for various purposes
like domU creation, running xentrace, etc... Such pages are
typed p2m_map_foreign. Note, it is the nature of such pages
that a refcnt is held during their stay in the p2m. The
refcnt is added and released in the low level ept function
atomic_write_ept_entry. That macro is converted to a function to allow
for such refcounting, which only applies to leaf entries in the ept.
Furthermore, please note that paging/sharing is disabled if the
controlling or hardware domain is pvh. Any enabling of those features
would need to ensure refcnt are properly maintained for foreign types,
or paging/sharing is skipped for foreign types.
Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
Reviewed-by: Tim Deegan <tim@xxxxxxx>
---
xen/arch/x86/mm.c | 2 +
xen/arch/x86/mm/mem_event.c | 11 ++++
xen/arch/x86/mm/p2m-ept.c | 109 ++++++++++++++++++++++++++++++--------
xen/arch/x86/mm/p2m-pt.c | 7 +++
xen/arch/x86/mm/p2m.c | 126 +++++++++++++++++++++++++++++++++++++++++---
xen/include/asm-x86/p2m.h | 7 +++
6 files changed, 234 insertions(+), 28 deletions(-)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d3459f4..dd8d98c 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4584,6 +4584,8 @@ int xenmem_add_to_physmap_one(
page = mfn_to_page(mfn);
break;
}
+ case XENMAPSPACE_gmfn_foreign:
+ return p2m_add_foreign(d, idx, gpfn, foreign_domid);
default:
break;
}
diff --git a/xen/arch/x86/mm/mem_event.c b/xen/arch/x86/mm/mem_event.c
index f84c383..40ae841 100644
--- a/xen/arch/x86/mm/mem_event.c
+++ b/xen/arch/x86/mm/mem_event.c
@@ -538,6 +538,12 @@ int mem_event_domctl(struct domain *d,
xen_domctl_mem_event_op_t *mec,
case XEN_DOMCTL_MEM_EVENT_OP_PAGING_ENABLE:
{
struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+ rc = -EOPNOTSUPP;
+ /* pvh fixme: p2m_is_foreign types need addressing */
+ if ( is_pvh_vcpu(current) || is_pvh_domain(hardware_domain) )
+ break;
+
rc = -ENODEV;
/* Only HAP is supported */
if ( !hap_enabled(d) )
@@ -620,6 +626,11 @@ int mem_event_domctl(struct domain *d,
xen_domctl_mem_event_op_t *mec,
{
case XEN_DOMCTL_MEM_EVENT_OP_SHARING_ENABLE:
{
+ rc = -EOPNOTSUPP;
+ /* pvh fixme: p2m_is_foreign types need addressing */
+ if ( is_pvh_vcpu(current) || is_pvh_domain(hardware_domain) )
+ break;
+
rc = -ENODEV;
/* Only HAP is supported */
if ( !hap_enabled(d) )
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index bb98945..9fda28d 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -36,8 +36,6 @@
#define atomic_read_ept_entry(__pepte) \
( (ept_entry_t) { .epte = read_atomic(&(__pepte)->epte) } )
-#define atomic_write_ept_entry(__pepte, __epte) \
- write_atomic(&(__pepte)->epte, (__epte).epte)
#define is_epte_present(ept_entry) ((ept_entry)->epte & 0x7)
#define is_epte_superpage(ept_entry) ((ept_entry)->sp)
@@ -46,6 +44,64 @@ static inline bool_t is_epte_valid(ept_entry_t *e)
return (e->epte != 0 && e->sa_p2mt != p2m_invalid);
}
+/* returns : 0 for success, -errno otherwise */
+static int atomic_write_ept_entry(ept_entry_t *entryptr, ept_entry_t new,
+ int level)
+{
+ int rc;
+ unsigned long oldmfn = INVALID_MFN;
+ bool_t check_foreign = (new.mfn != entryptr->mfn ||
+ new.sa_p2mt != entryptr->sa_p2mt);
+
+ if ( level )
+ {
+ ASSERT(!is_epte_superpage(&new) || !p2m_is_foreign(new.sa_p2mt));
+ write_atomic(&entryptr->epte, new.epte);
+ return 0;
+ }
+
+ if ( unlikely(p2m_is_foreign(new.sa_p2mt)) )
+ {
+ rc = -EINVAL;
+ if ( !is_epte_present(&new) )
+ goto out;
+
+ if ( check_foreign )
+ {
+ struct domain *fdom;
+
+ if ( !mfn_valid(new.mfn) )
+ goto out;
+
+ rc = -ESRCH;
+ fdom = page_get_owner(mfn_to_page(new.mfn));
+ if ( fdom == NULL )
+ goto out;
+
+ /* get refcount on the page */
+ rc = -EBUSY;
+ if ( !get_page(mfn_to_page(new.mfn), fdom) )
+ goto out;
+ }
+ }
+
+ if ( unlikely(p2m_is_foreign(entryptr->sa_p2mt)) && check_foreign )
+ oldmfn = entryptr->mfn;
+
+ write_atomic(&entryptr->epte, new.epte);
+
+ if ( unlikely(oldmfn != INVALID_MFN) )
+ put_page(mfn_to_page(oldmfn));
+
+ rc = 0;
+
+ out:
+ if ( rc )
+ gdprintk(XENLOG_ERR, "epte o:%"PRIx64" n:%"PRIx64" rc:%d\n",
+ entryptr->epte, new.epte, rc);
+ return rc;
+}
+
static void ept_p2m_type_to_flags(ept_entry_t *entry, p2m_type_t type,
p2m_access_t access)
{
/* First apply type permissions */
@@ -275,8 +331,9 @@ static int ept_next_level(struct p2m_domain *p2m, bool_t
read_only,
* present entries in the given page table, optionally marking the entries
* also for their subtrees needing P2M type re-calculation.
*/
-static bool_t ept_invalidate_emt(mfn_t mfn, bool_t recalc)
+static bool_t ept_invalidate_emt(mfn_t mfn, bool_t recalc, int level)
{
+ int rc;
ept_entry_t *epte = map_domain_page(mfn_x(mfn));
unsigned int i;
bool_t changed = 0;
@@ -292,7 +349,8 @@ static bool_t ept_invalidate_emt(mfn_t mfn, bool_t recalc)
e.emt = MTRR_NUM_TYPES;
if ( recalc )
e.recalc = 1;
- atomic_write_ept_entry(&epte[i], e);
+ rc = atomic_write_ept_entry(&epte[i], e, level);
+ ASSERT(rc == 0);
changed = 1;
}
@@ -316,7 +374,7 @@ static int ept_invalidate_emt_range(struct p2m_domain *p2m,
ept_entry_t *table;
unsigned long gfn_remainder = first_gfn;
unsigned int i, index;
- int rc = 0, ret = GUEST_TABLE_MAP_FAILED;
+ int wrc, rc = 0, ret = GUEST_TABLE_MAP_FAILED;
table = map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m)));
for ( i = ept_get_wl(&p2m->ept); i > target; --i )
@@ -342,7 +400,8 @@ static int ept_invalidate_emt_range(struct p2m_domain *p2m,
rc = -ENOMEM;
goto out;
}
- atomic_write_ept_entry(&table[index], split_ept_entry);
+ wrc = atomic_write_ept_entry(&table[index], split_ept_entry, i);
+ ASSERT(wrc == 0);
for ( ; i > target; --i )
if ( !ept_next_level(p2m, 1, &table, &gfn_remainder, i) )
@@ -361,7 +420,8 @@ static int ept_invalidate_emt_range(struct p2m_domain *p2m,
{
e.emt = MTRR_NUM_TYPES;
e.recalc = 1;
- atomic_write_ept_entry(&table[index], e);
+ wrc = atomic_write_ept_entry(&table[index], e, target);
+ ASSERT(wrc == 0);
rc = 1;
}
}
@@ -390,7 +450,7 @@ static int resolve_misconfig(struct p2m_domain *p2m,
unsigned long gfn)
unsigned int level = ept_get_wl(ept);
unsigned long mfn = ept_get_asr(ept);
ept_entry_t *epte;
- int rc = 0;
+ int wrc, rc = 0;
if ( !mfn )
return 0;
@@ -431,7 +491,8 @@ static int resolve_misconfig(struct p2m_domain *p2m,
unsigned long gfn)
ept_p2m_type_to_flags(&e, e.sa_p2mt, e.access);
}
e.recalc = 0;
- atomic_write_ept_entry(&epte[i], e);
+ wrc = atomic_write_ept_entry(&epte[i], e, level);
+ ASSERT(wrc == 0);
}
}
else
@@ -465,7 +526,8 @@ static int resolve_misconfig(struct p2m_domain *p2m,
unsigned long gfn)
{
if ( ept_split_super_page(p2m, &e, level, level - 1) )
{
- atomic_write_ept_entry(&epte[i], e);
+ wrc = atomic_write_ept_entry(&epte[i], e, level);
+ ASSERT(wrc == 0);
unmap_domain_page(epte);
mfn = e.mfn;
continue;
@@ -479,7 +541,8 @@ static int resolve_misconfig(struct p2m_domain *p2m,
unsigned long gfn)
e.recalc = 0;
if ( recalc && p2m_is_changeable(e.sa_p2mt) )
ept_p2m_type_to_flags(&e, e.sa_p2mt, e.access);
- atomic_write_ept_entry(&epte[i], e);
+ wrc = atomic_write_ept_entry(&epte[i], e, level);
+ ASSERT(wrc == 0);
}
rc = 1;
@@ -489,11 +552,12 @@ static int resolve_misconfig(struct p2m_domain *p2m,
unsigned long gfn)
if ( e.emt == MTRR_NUM_TYPES )
{
ASSERT(is_epte_present(&e));
- ept_invalidate_emt(_mfn(e.mfn), e.recalc);
+ ept_invalidate_emt(_mfn(e.mfn), e.recalc, level);
smp_wmb();
e.emt = 0;
e.recalc = 0;
- atomic_write_ept_entry(&epte[i], e);
+ wrc = atomic_write_ept_entry(&epte[i], e, level);
+ ASSERT(wrc == 0);
unmap_domain_page(epte);
rc = 1;
}
@@ -585,6 +649,7 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn,
mfn_t mfn,
ASSERT((target == 2 && hvm_hap_has_1gb()) ||
(target == 1 && hvm_hap_has_2mb()) ||
(target == 0));
+ ASSERT(!p2m_is_foreign(p2mt) || target == 0);
table = map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m)));
@@ -649,7 +714,8 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn,
mfn_t mfn,
/* now install the newly split ept sub-tree */
/* NB: please make sure domian is paused and no in-fly VT-d DMA. */
- atomic_write_ept_entry(ept_entry, split_ept_entry);
+ rc = atomic_write_ept_entry(ept_entry, split_ept_entry, i);
+ ASSERT(rc == 0);
/* then move to the level we want to make real changes */
for ( ; i > target; i-- )
@@ -688,11 +754,12 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn,
mfn_t mfn,
ept_p2m_type_to_flags(&new_entry, p2mt, p2ma);
}
- atomic_write_ept_entry(ept_entry, new_entry);
-
- /* Track the highest gfn for which we have ever had a valid mapping */
- if ( p2mt != p2m_invalid &&
- (gfn + (1UL << order) - 1 > p2m->max_mapped_pfn) )
+ rc = atomic_write_ept_entry(ept_entry, new_entry, target);
+ if ( unlikely(rc) )
+ old_entry.epte = 0;
+ else if ( p2mt != p2m_invalid &&
+ (gfn + (1UL << order) - 1 > p2m->max_mapped_pfn) )
+ /* Track the highest gfn for which we have ever had a valid mapping */
p2m->max_mapped_pfn = gfn + (1UL << order) - 1;
out:
@@ -893,7 +960,7 @@ static void ept_change_entry_type_global(struct p2m_domain
*p2m,
if ( !mfn )
return;
- if ( ept_invalidate_emt(_mfn(mfn), 1) )
+ if ( ept_invalidate_emt(_mfn(mfn), 1, ept_get_wl(&p2m->ept)) )
ept_sync_domain(p2m);
}
@@ -951,7 +1018,7 @@ static void ept_memory_type_changed(struct p2m_domain *p2m)
if ( !mfn )
return;
- if ( ept_invalidate_emt(_mfn(mfn), 0) )
+ if ( ept_invalidate_emt(_mfn(mfn), 0, ept_get_wl(&p2m->ept)) )
ept_sync_domain(p2m);
}
diff --git a/xen/arch/x86/mm/p2m-pt.c b/xen/arch/x86/mm/p2m-pt.c
index cd9867a..a1794d0 100644
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -513,6 +513,13 @@ p2m_pt_set_entry(struct p2m_domain *p2m, unsigned long
gfn, mfn_t mfn,
__trace_var(TRC_MEM_SET_P2M_ENTRY, 0, sizeof(t), &t);
}
+ if ( unlikely(p2m_is_foreign(p2mt)) )
+ {
+ /* pvh fixme: foreign types are only supported on ept at present */
+ gdprintk(XENLOG_WARNING, "Unimplemented foreign p2m type.\n");
+ return -EINVAL;
+ }
+
/* Carry out any eventually pending earlier changes first. */
rc = do_recalc(p2m, gfn);
if ( rc < 0 )
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index b50747a..642ec28 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -36,6 +36,7 @@
#include <xen/event.h>
#include <asm/hvm/nestedhvm.h>
#include <asm/hvm/svm/amd-iommu-proto.h>
+#include <xsm/xsm.h>
#include "mm-locks.h"
@@ -311,14 +312,20 @@ struct page_info *get_page_from_gfn_p2m(
/* Fast path: look up and get out */
p2m_read_lock(p2m);
mfn = __get_gfn_type_access(p2m, gfn, t, a, 0, NULL, 0);
- if ( (p2m_is_ram(*t) || p2m_is_grant(*t))
- && mfn_valid(mfn)
+ if ( p2m_is_any_ram(*t) && mfn_valid(mfn)
&& !((q & P2M_UNSHARE) && p2m_is_shared(*t)) )
{
page = mfn_to_page(mfn);
- if ( !get_page(page, d)
- /* Page could be shared */
- && !get_page(page, dom_cow) )
+ if ( unlikely(p2m_is_foreign(*t)) )
+ {
+ struct domain *fdom = page_get_owner_and_reference(page);
+ ASSERT(fdom != d);
+ if ( fdom == NULL )
+ page = NULL;
+ }
+ else if ( !get_page(page, d)
+ /* Page could be shared */
+ && !get_page(page, dom_cow) )
page = NULL;
}
p2m_read_unlock(p2m);
@@ -468,6 +475,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
return rc;
}
+/*
+ * pvh fixme: when adding support for pvh non-hardware domains, this path must
+ * cleanup any foreign p2m types (release refcnts on them).
+ */
void p2m_teardown(struct p2m_domain *p2m)
/* Return all the p2m pages to Xen.
* We know we don't have any extra mappings to these pages */
@@ -836,8 +847,8 @@ static int set_typed_p2m_entry(struct domain *d, unsigned
long gfn, mfn_t mfn,
}
/* Set foreign mfn in the given guest's p2m table. */
-static int __attribute__((unused))
-set_foreign_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
+static int set_foreign_p2m_entry(struct domain *d, unsigned long gfn,
+ mfn_t mfn)
{
return set_typed_p2m_entry(d, gfn, mfn, p2m_map_foreign);
}
@@ -1794,6 +1805,107 @@ out_p2m_audit:
#endif /* P2M_AUDIT */
/*
+ * Add frame from foreign domain to target domain's physmap. Similar to
+ * XENMAPSPACE_gmfn but the frame is foreign being mapped into current,
+ * and is not removed from foreign domain.
+ *
+ * Usage: - libxl on pvh dom0 creating a guest and doing privcmd_ioctl_mmap.
+ * - xentrace running on dom0 mapping xenheap pages. foreigndom would
+ * be DOMID_XEN in such a case.
+ * etc..
+ *
+ * Side Effect: the mfn for fgfn will be refcounted in lower level routines
+ * so it is not lost while mapped here. The refcnt is released
+ * via the XENMEM_remove_from_physmap path.
+ *
+ * Returns: 0 ==> success
+ */
+int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
+ unsigned long gpfn, domid_t foreigndom)
+{
+ p2m_type_t p2mt, p2mt_prev;
+ unsigned long prev_mfn, mfn;
+ struct page_info *page;
+ int rc;
+ struct domain *fdom;
+
+ ASSERT(tdom);
+ if ( foreigndom == DOMID_SELF || !is_pvh_domain(tdom) )
+ return -EINVAL;
+ /*
+ * pvh fixme: until support is added to p2m teardown code to cleanup any
+ * foreign entries, limit this to hardware domain only.
+ */
+ if ( !is_hardware_domain(tdom) )
+ return -EPERM;
+
+ if ( foreigndom == DOMID_XEN )
+ fdom = rcu_lock_domain(dom_xen);
+ else
+ fdom = rcu_lock_domain_by_id(foreigndom);
+ if ( fdom == NULL )
+ return -ESRCH;
+
+ rc = -EINVAL;
+ if ( tdom == fdom )
+ goto out;
+
+ rc = xsm_map_gmfn_foreign(XSM_TARGET, tdom, fdom);
+ if ( rc )
+ goto out;
+
+ /*
+ * Take a refcnt on the mfn. NB: following supported for foreign mapping:
+ * ram_rw | ram_logdirty | ram_ro | paging_out.
+ */
+ page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC);
+ if ( !page ||
+ !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
+ {
+ if ( page )
+ put_page(page);
+ rc = -EINVAL;
+ goto out;
+ }
+ mfn = mfn_x(page_to_mfn(page));
+
+ /* Remove previously mapped page if it is present. */
+ prev_mfn = mfn_x(get_gfn(tdom, gpfn, &p2mt_prev));
+ if ( mfn_valid(_mfn(prev_mfn)) )
+ {
+ if ( is_xen_heap_mfn(prev_mfn) )
+ /* Xen heap frames are simply unhooked from this phys slot */
+ guest_physmap_remove_page(tdom, gpfn, prev_mfn, 0);
+ else
+ /* Normal domain memory is freed, to avoid leaking memory. */
+ guest_remove_page(tdom, gpfn);
+ }
+ /*
+ * Create the new mapping. Can't use guest_physmap_add_page() because it
+ * will update the m2p table which will result in mfn -> gpfn of dom0
+ * and not fgfn of domU.
+ */
+ rc = set_foreign_p2m_entry(tdom, gpfn, _mfn(mfn));
+ if ( rc )
+ gdprintk(XENLOG_WARNING, "set_foreign_p2m_entry failed. "
+ "gpfn:%lx mfn:%lx fgfn:%lx td:%d fd:%d\n",
+ gpfn, mfn, fgfn, tdom->domain_id, fdom->domain_id);
+
+ put_page(page);
+
+ /*
+ * This put_gfn for the above get_gfn for prev_mfn. We must do this
+ * after set_foreign_p2m_entry so another cpu doesn't populate the gpfn
+ * before us.
+ */
+ put_gfn(tdom, gpfn);
+
+out:
+ if ( fdom )
+ rcu_unlock_domain(fdom);
+ return rc;
+}
+/*
* Local variables:
* mode: C
* c-file-style: "BSD"
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 027f011..d0cfdac 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -188,6 +188,10 @@ typedef unsigned int p2m_query_t;
#define p2m_is_broken(_t) (p2m_to_mask(_t) & P2M_BROKEN_TYPES)
#define p2m_is_foreign(_t) (p2m_to_mask(_t) & p2m_to_mask(p2m_map_foreign))
+#define p2m_is_any_ram(_t) (p2m_to_mask(_t) & \
+ (P2M_RAM_TYPES | P2M_GRANT_TYPES | \
+ p2m_to_mask(p2m_map_foreign)))
+
/* Per-p2m-table state */
struct p2m_domain {
/* Lock that protects updates to the p2m */
@@ -532,6 +536,9 @@ int p2m_is_logdirty_range(struct p2m_domain *, unsigned
long start,
int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn);
+/* Add foreign mapping to the guest's p2m table. */
+int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
+ unsigned long gpfn, domid_t foreign_domid);
/*
* Populate-on-demand
--
1.8.3.1
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