* [PATCH v2 1/2] x86/paging: tidy paging_mfn_is_dirty()
2021-12-06 13:21 [PATCH v2 0/2] x86/paging: address observation made while working on XSA-387 Jan Beulich
@ 2021-12-06 13:25 ` Jan Beulich
2022-01-11 16:59 ` Andrew Cooper
2021-12-06 13:25 ` [PATCH v2 2/2] x86/paging: replace most mfn_valid() in log-dirty handling Jan Beulich
2022-01-04 9:55 ` Ping: [PATCH v2 0/2] x86/paging: address observation made while working on XSA-387 Jan Beulich
2 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2021-12-06 13:25 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Wei Liu, Roger Pau Monné, George Dunlap
The function returning a boolean indicator, make it return bool. Also
constify its struct domain parameter, albeit requiring to also adjust
mm_locked_by_me(). Furthermore the function is used by shadow code only.
Since mm_locked_by_me() needs touching anyway, also switch its return
type to bool.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Change return type of mm_locked_by_me().
--- a/xen/arch/x86/mm/mm-locks.h
+++ b/xen/arch/x86/mm/mm-locks.h
@@ -40,7 +40,7 @@ static inline void mm_lock_init(mm_lock_
l->unlock_level = 0;
}
-static inline int mm_locked_by_me(mm_lock_t *l)
+static inline bool mm_locked_by_me(const mm_lock_t *l)
{
return (l->lock.recurse_cpu == current->processor);
}
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -351,14 +351,14 @@ void paging_mark_dirty(struct domain *d,
paging_mark_pfn_dirty(d, pfn);
}
-
+#ifdef CONFIG_SHADOW_PAGING
/* Is this guest page dirty? */
-int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn)
+bool paging_mfn_is_dirty(const struct domain *d, mfn_t gmfn)
{
pfn_t pfn;
mfn_t mfn, *l4, *l3, *l2;
unsigned long *l1;
- int rv;
+ bool dirty;
ASSERT(paging_locked_by_me(d));
ASSERT(paging_mode_log_dirty(d));
@@ -367,36 +367,37 @@ int paging_mfn_is_dirty(struct domain *d
pfn = _pfn(get_gpfn_from_mfn(mfn_x(gmfn)));
/* Invalid pages can't be dirty. */
if ( unlikely(!VALID_M2P(pfn_x(pfn))) )
- return 0;
+ return false;
mfn = d->arch.paging.log_dirty.top;
if ( !mfn_valid(mfn) )
- return 0;
+ return false;
l4 = map_domain_page(mfn);
mfn = l4[L4_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l4);
if ( !mfn_valid(mfn) )
- return 0;
+ return false;
l3 = map_domain_page(mfn);
mfn = l3[L3_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l3);
if ( !mfn_valid(mfn) )
- return 0;
+ return false;
l2 = map_domain_page(mfn);
mfn = l2[L2_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l2);
if ( !mfn_valid(mfn) )
- return 0;
+ return false;
l1 = map_domain_page(mfn);
- rv = test_bit(L1_LOGDIRTY_IDX(pfn), l1);
+ dirty = test_bit(L1_LOGDIRTY_IDX(pfn), l1);
unmap_domain_page(l1);
- return rv;
-}
+ return dirty;
+}
+#endif
/* Read a domain's log-dirty bitmap and stats. If the operation is a CLEAN,
* clear the bitmap and stats as well. */
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -173,7 +173,7 @@ void paging_mark_pfn_dirty(struct domain
/* is this guest page dirty?
* This is called from inside paging code, with the paging lock held. */
-int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
+bool paging_mfn_is_dirty(const struct domain *d, mfn_t gmfn);
/*
* Log-dirty radix tree indexing:
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v2 2/2] x86/paging: replace most mfn_valid() in log-dirty handling
2021-12-06 13:21 [PATCH v2 0/2] x86/paging: address observation made while working on XSA-387 Jan Beulich
2021-12-06 13:25 ` [PATCH v2 1/2] x86/paging: tidy paging_mfn_is_dirty() Jan Beulich
@ 2021-12-06 13:25 ` Jan Beulich
2022-01-11 16:59 ` Andrew Cooper
2022-01-04 9:55 ` Ping: [PATCH v2 0/2] x86/paging: address observation made while working on XSA-387 Jan Beulich
2 siblings, 1 reply; 6+ messages in thread
From: Jan Beulich @ 2021-12-06 13:25 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Wei Liu, Roger Pau Monné, George Dunlap
Top level table and intermediate table entries get explicitly set to
INVALID_MFN when un-allocated. There's therefore no need to use the more
expensive mfn_valid() when checking for that sentinel.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: New.
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -74,7 +74,7 @@ static mfn_t paging_new_log_dirty_leaf(s
{
mfn_t mfn = paging_new_log_dirty_page(d);
- if ( mfn_valid(mfn) )
+ if ( !mfn_eq(mfn, INVALID_MFN) )
clear_domain_page(mfn);
return mfn;
@@ -84,7 +84,8 @@ static mfn_t paging_new_log_dirty_leaf(s
static mfn_t paging_new_log_dirty_node(struct domain *d)
{
mfn_t mfn = paging_new_log_dirty_page(d);
- if ( mfn_valid(mfn) )
+
+ if ( !mfn_eq(mfn, INVALID_MFN) )
{
int i;
mfn_t *node = map_domain_page(mfn);
@@ -98,7 +99,7 @@ static mfn_t paging_new_log_dirty_node(s
/* get the top of the log-dirty bitmap trie */
static mfn_t *paging_map_log_dirty_bitmap(struct domain *d)
{
- if ( likely(mfn_valid(d->arch.paging.log_dirty.top)) )
+ if ( likely(!mfn_eq(d->arch.paging.log_dirty.top, INVALID_MFN)) )
return map_domain_page(d->arch.paging.log_dirty.top);
return NULL;
}
@@ -116,7 +117,7 @@ static int paging_free_log_dirty_bitmap(
paging_lock(d);
- if ( !mfn_valid(d->arch.paging.log_dirty.top) )
+ if ( mfn_eq(d->arch.paging.log_dirty.top, INVALID_MFN) )
{
paging_unlock(d);
return 0;
@@ -143,20 +144,20 @@ static int paging_free_log_dirty_bitmap(
for ( ; i4 < LOGDIRTY_NODE_ENTRIES; i4++, i3 = 0 )
{
- if ( !mfn_valid(l4[i4]) )
+ if ( mfn_eq(l4[i4], INVALID_MFN) )
continue;
l3 = map_domain_page(l4[i4]);
for ( ; i3 < LOGDIRTY_NODE_ENTRIES; i3++ )
{
- if ( !mfn_valid(l3[i3]) )
+ if ( mfn_eq(l3[i3], INVALID_MFN) )
continue;
l2 = map_domain_page(l3[i3]);
for ( i2 = 0; i2 < LOGDIRTY_NODE_ENTRIES; i2++ )
- if ( mfn_valid(l2[i2]) )
+ if ( !mfn_eq(l2[i2], INVALID_MFN) )
paging_free_log_dirty_page(d, l2[i2]);
unmap_domain_page(l2);
@@ -288,35 +289,35 @@ void paging_mark_pfn_dirty(struct domain
/* Recursive: this is called from inside the shadow code */
paging_lock_recursive(d);
- if ( unlikely(!mfn_valid(d->arch.paging.log_dirty.top)) )
+ if ( unlikely(mfn_eq(d->arch.paging.log_dirty.top, INVALID_MFN)) )
{
d->arch.paging.log_dirty.top = paging_new_log_dirty_node(d);
- if ( unlikely(!mfn_valid(d->arch.paging.log_dirty.top)) )
+ if ( unlikely(mfn_eq(d->arch.paging.log_dirty.top, INVALID_MFN)) )
goto out;
}
l4 = paging_map_log_dirty_bitmap(d);
mfn = l4[i4];
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
l4[i4] = mfn = paging_new_log_dirty_node(d);
unmap_domain_page(l4);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
goto out;
l3 = map_domain_page(mfn);
mfn = l3[i3];
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
l3[i3] = mfn = paging_new_log_dirty_node(d);
unmap_domain_page(l3);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
goto out;
l2 = map_domain_page(mfn);
mfn = l2[i2];
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
l2[i2] = mfn = paging_new_log_dirty_leaf(d);
unmap_domain_page(l2);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
goto out;
l1 = map_domain_page(mfn);
@@ -370,25 +371,25 @@ bool paging_mfn_is_dirty(const struct do
return false;
mfn = d->arch.paging.log_dirty.top;
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
return false;
l4 = map_domain_page(mfn);
mfn = l4[L4_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l4);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
return false;
l3 = map_domain_page(mfn);
mfn = l3[L3_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l3);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
return false;
l2 = map_domain_page(mfn);
mfn = l2[L2_LOGDIRTY_IDX(pfn)];
unmap_domain_page(l2);
- if ( !mfn_valid(mfn) )
+ if ( mfn_eq(mfn, INVALID_MFN) )
return false;
l1 = map_domain_page(mfn);
@@ -477,17 +478,18 @@ static int paging_log_dirty_op(struct do
for ( ; (pages < sc->pages) && (i4 < LOGDIRTY_NODE_ENTRIES); i4++, i3 = 0 )
{
- l3 = (l4 && mfn_valid(l4[i4])) ? map_domain_page(l4[i4]) : NULL;
+ l3 = ((l4 && !mfn_eq(l4[i4], INVALID_MFN)) ?
+ map_domain_page(l4[i4]) : NULL);
for ( ; (pages < sc->pages) && (i3 < LOGDIRTY_NODE_ENTRIES); i3++ )
{
- l2 = ((l3 && mfn_valid(l3[i3])) ?
+ l2 = ((l3 && !mfn_eq(l3[i3], INVALID_MFN)) ?
map_domain_page(l3[i3]) : NULL);
for ( i2 = 0;
(pages < sc->pages) && (i2 < LOGDIRTY_NODE_ENTRIES);
i2++ )
{
unsigned int bytes = PAGE_SIZE;
- l1 = ((l2 && mfn_valid(l2[i2])) ?
+ l1 = ((l2 && !mfn_eq(l2[i2], INVALID_MFN)) ?
map_domain_page(l2[i2]) : NULL);
if ( unlikely(((sc->pages - pages + 7) >> 3) < bytes) )
bytes = (unsigned int)((sc->pages - pages + 7) >> 3);
^ permalink raw reply [flat|nested] 6+ messages in thread