|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] x86: rework paging_log_dirty_op to work with hvm guests
commit a809eeea06d20b115d78f12e473502bcb6209844
Author: Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Fri May 15 10:08:33 2015 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 15 10:08:33 2015 +0200
x86: rework paging_log_dirty_op to work with hvm guests
When the caller of paging_log_dirty_op is a hvm guest Xen would choke when
trying to copy the dirty bitmap to the guest because the paging lock is
already held.
Fix this by independently mapping each page of the guest bitmap as needed
without the paging lock held.
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Tim Deegan <tim@xxxxxxx>
---
xen/arch/x86/mm/paging.c | 97 +++++++++++++++++++++++++++++++++++++-----
xen/include/asm-x86/domain.h | 1 +
2 files changed, 87 insertions(+), 11 deletions(-)
diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index 59d4720..5eee88c 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -408,6 +408,51 @@ int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn)
return rv;
}
+static inline void *map_dirty_bitmap(XEN_GUEST_HANDLE_64(uint8) dirty_bitmap,
+ unsigned long pages,
+ struct page_info **page)
+{
+ uint32_t pfec = PFEC_page_present | PFEC_write_access;
+ unsigned long gfn;
+ p2m_type_t p2mt;
+
+ gfn = paging_gva_to_gfn(current,
+ (unsigned long)(dirty_bitmap.p + (pages >> 3)),
+ &pfec);
+ if ( gfn == INVALID_GFN )
+ return NULL;
+
+ *page = get_page_from_gfn(current->domain, gfn, &p2mt, P2M_UNSHARE);
+
+ if ( !p2m_is_ram(p2mt) )
+ {
+ put_page(*page);
+ return NULL;
+ }
+ if ( p2m_is_paging(p2mt) )
+ {
+ put_page(*page);
+ p2m_mem_paging_populate(current->domain, gfn);
+ return NULL;
+ }
+ if ( p2m_is_shared(p2mt) || p2m_is_discard_write(p2mt) )
+ {
+ put_page(*page);
+ return NULL;
+ }
+
+ return __map_domain_page(*page);
+}
+
+static inline void unmap_dirty_bitmap(void *addr, struct page_info *page)
+{
+ if ( addr != NULL )
+ {
+ unmap_domain_page(addr);
+ put_page(page);
+ }
+}
+
/* Read a domain's log-dirty bitmap and stats. If the operation is a CLEAN,
* clear the bitmap and stats as well. */
@@ -420,7 +465,11 @@ static int paging_log_dirty_op(struct domain *d,
mfn_t *l4 = NULL, *l3 = NULL, *l2 = NULL;
unsigned long *l1 = NULL;
int i4, i3, i2;
+ uint8_t *dirty_bitmap;
+ struct page_info *page;
+ unsigned long index_mapped;
+ again:
if ( !resuming )
{
domain_pause(d);
@@ -433,6 +482,14 @@ static int paging_log_dirty_op(struct domain *d,
p2m_flush_hardware_cached_dirty(d);
}
+ index_mapped = resuming ? d->arch.paging.preempt.log_dirty.done : 0;
+ dirty_bitmap = map_dirty_bitmap(sc->dirty_bitmap, index_mapped, &page);
+ if ( dirty_bitmap == NULL )
+ {
+ domain_unpause(d);
+ return -EFAULT;
+ }
+
paging_lock(d);
if ( !d->arch.paging.preempt.dom )
@@ -472,18 +529,18 @@ static int paging_log_dirty_op(struct domain *d,
l4 = paging_map_log_dirty_bitmap(d);
i4 = d->arch.paging.preempt.log_dirty.i4;
i3 = d->arch.paging.preempt.log_dirty.i3;
+ i2 = d->arch.paging.preempt.log_dirty.i2;
pages = d->arch.paging.preempt.log_dirty.done;
for ( ; (pages < sc->pages) && (i4 < LOGDIRTY_NODE_ENTRIES); i4++, i3 = 0 )
{
l3 = (l4 && mfn_valid(l4[i4])) ? map_domain_page(mfn_x(l4[i4])) : NULL;
- for ( ; (pages < sc->pages) && (i3 < LOGDIRTY_NODE_ENTRIES); i3++ )
+ for ( ; (pages < sc->pages) && (i3 < LOGDIRTY_NODE_ENTRIES);
+ i3++, i2 = 0 )
{
l2 = ((l3 && mfn_valid(l3[i3])) ?
map_domain_page(mfn_x(l3[i3])) : NULL);
- for ( i2 = 0;
- (pages < sc->pages) && (i2 < LOGDIRTY_NODE_ENTRIES);
- i2++ )
+ for ( ; (pages < sc->pages) && (i2 < LOGDIRTY_NODE_ENTRIES); i2++ )
{
unsigned int bytes = PAGE_SIZE;
l1 = ((l2 && mfn_valid(l2[i2])) ?
@@ -492,15 +549,28 @@ static int paging_log_dirty_op(struct domain *d,
bytes = (unsigned int)((sc->pages - pages + 7) >> 3);
if ( likely(peek) )
{
- if ( (l1 ? copy_to_guest_offset(sc->dirty_bitmap,
- pages >> 3, (uint8_t *)l1,
- bytes)
- : clear_guest_offset(sc->dirty_bitmap,
- pages >> 3, bytes)) != 0 )
+ if ( pages >> (3 + PAGE_SHIFT) !=
+ index_mapped >> (3 + PAGE_SHIFT) )
{
- rv = -EFAULT;
- goto out;
+ /* We need to map next page */
+ d->arch.paging.preempt.log_dirty.i4 = i4;
+ d->arch.paging.preempt.log_dirty.i3 = i3;
+ d->arch.paging.preempt.log_dirty.i2 = i2;
+ d->arch.paging.preempt.log_dirty.done = pages;
+ d->arch.paging.preempt.dom = current->domain;
+ d->arch.paging.preempt.op = sc->op;
+ resuming = 1;
+ paging_unlock(d);
+ unmap_dirty_bitmap(dirty_bitmap, page);
+ goto again;
}
+ ASSERT(((pages >> 3) % PAGE_SIZE) + bytes <= PAGE_SIZE);
+ if ( l1 )
+ memcpy(dirty_bitmap + ((pages >> 3) % PAGE_SIZE), l1,
+ bytes);
+ else
+ memset(dirty_bitmap + ((pages >> 3) % PAGE_SIZE), 0,
+ bytes);
}
pages += bytes << 3;
if ( l1 )
@@ -517,6 +587,7 @@ static int paging_log_dirty_op(struct domain *d,
{
d->arch.paging.preempt.log_dirty.i4 = i4;
d->arch.paging.preempt.log_dirty.i3 = i3 + 1;
+ d->arch.paging.preempt.log_dirty.i2 = 0;
rv = -ERESTART;
break;
}
@@ -529,6 +600,7 @@ static int paging_log_dirty_op(struct domain *d,
{
d->arch.paging.preempt.log_dirty.i4 = i4 + 1;
d->arch.paging.preempt.log_dirty.i3 = 0;
+ d->arch.paging.preempt.log_dirty.i2 = 0;
rv = -ERESTART;
}
if ( rv )
@@ -558,6 +630,7 @@ static int paging_log_dirty_op(struct domain *d,
if ( rv )
{
/* Never leave the domain paused on real errors. */
+ unmap_dirty_bitmap(dirty_bitmap, page);
ASSERT(rv == -ERESTART);
return rv;
}
@@ -570,12 +643,14 @@ static int paging_log_dirty_op(struct domain *d,
* paging modes (shadow or hap). Safe because the domain is paused. */
d->arch.paging.log_dirty.clean_dirty_bitmap(d);
}
+ unmap_dirty_bitmap(dirty_bitmap, page);
domain_unpause(d);
return rv;
out:
d->arch.paging.preempt.dom = NULL;
paging_unlock(d);
+ unmap_dirty_bitmap(dirty_bitmap, page);
domain_unpause(d);
if ( l1 )
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 45b5283..f4375c2 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -204,6 +204,7 @@ struct paging_domain {
unsigned long done:PADDR_BITS - PAGE_SHIFT;
unsigned long i4:PAGETABLE_ORDER;
unsigned long i3:PAGETABLE_ORDER;
+ unsigned long i2:PAGETABLE_ORDER;
} log_dirty;
};
} preempt;
--
generated by git-patchbot for /home/xen/git/xen.git#master
_______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |