Mailing List Archive

commit c44c0dc35889848ee27549ac3455314e236cfc3d
Author: Jan Beulich <jbeulich@suse.com>
AuthorDate: Mon Dec 12 12:18:41 2022 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Mon Dec 12 12:18:41 2022 +0100

x86/mm: rename PGC_page_table to PGC_shadowed_pt

The original name didn't express the purpose of the flag: It is being
set once a page table page obtains a shadow, and it is removed when the
last shadow of a page was destroyed.

In set_tlbflush_timestamp() also remove the 2nd half of the condition as
being redundant (PGC_shadowed_pt can't be set on a page without shadow
mode being enabled on the owning domain).

Requested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
xen/arch/x86/include/asm/mm.h | 6 +++---
xen/arch/x86/mm.c | 3 +--
xen/arch/x86/mm/p2m-pod.c | 4 ++--
xen/arch/x86/mm/shadow/common.c | 20 ++++++++++----------
xen/arch/x86/mm/shadow/private.h | 8 ++++----
5 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index 2c5f856067..c4240a94d2 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -70,9 +70,9 @@
/* Page is Xen heap? */
#define _PGC_xen_heap PG_shift(2)
#define PGC_xen_heap PG_mask(1, 2)
- /* Set when is using a page as a page table */
-#define _PGC_page_table PG_shift(3)
-#define PGC_page_table PG_mask(1, 3)
+ /* Set when a page table page has been shadowed. */
+#define _PGC_shadowed_pt PG_shift(3)
+#define PGC_shadowed_pt PG_mask(1, 3)
/* Page is broken? */
#define _PGC_broken PG_shift(4)
#define PGC_broken PG_mask(1, 4)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 68f9989e1f..8b9740f575 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -591,8 +591,7 @@ static inline void set_tlbflush_timestamp(struct page_info *page)
* 2. Shadow mode reuses this field for shadowed page tables to store
* flags info -- we don't want to conflict with that.
*/
- if ( !(page->count_info & PGC_page_table) ||
- !shadow_mode_enabled(page_get_owner(page)) )
+ if ( !(page->count_info & PGC_shadowed_pt) )
page_set_tlbflush_timestamp(page);
}

diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
index fc110506dc..2490c841f9 100644
--- a/xen/arch/x86/mm/p2m-pod.c
+++ b/xen/arch/x86/mm/p2m-pod.c
@@ -803,7 +803,7 @@ p2m_pod_zero_check_superpage(struct p2m_domain *p2m, gfn_t gfn)
for ( k = 0, page = mfn_to_page(mfn); k < n; ++k, ++page )
if ( is_special_page(page) ||
!(page->count_info & PGC_allocated) ||
- (page->count_info & PGC_page_table) ||
+ (page->count_info & PGC_shadowed_pt) ||
(page->count_info & PGC_count_mask) > max_ref )
goto out;
}
@@ -946,7 +946,7 @@ p2m_pod_zero_check(struct p2m_domain *p2m, const gfn_t *gfns, unsigned int count

if ( !is_special_page(pg) &&
(pg->count_info & PGC_allocated) &&
- !(pg->count_info & PGC_page_table) &&
+ !(pg->count_info & PGC_shadowed_pt) &&
((pg->count_info & PGC_count_mask) <= max_ref) )
map[i] = map_domain_page(mfns[i]);
}
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index a8404f97f6..cae1d9190c 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -185,7 +185,7 @@ static void sh_oos_audit(struct domain *d)
BUG();
}
pg = mfn_to_page(oos[idx]);
- if ( !(pg->count_info & PGC_page_table) )
+ if ( !(pg->count_info & PGC_shadowed_pt) )
{
printk("%s: idx %x gmfn %lx not a pt (count %lx)\n",
__func__, idx, mfn_x(oos[idx]), pg->count_info);
@@ -716,7 +716,7 @@ void shadow_promote(struct domain *d, mfn_t gmfn, unsigned int type)
|| d->is_shutting_down);

/* Is the page already shadowed? */
- if ( !test_and_set_bit(_PGC_page_table, &page->count_info) )
+ if ( !test_and_set_bit(_PGC_shadowed_pt, &page->count_info) )
{
page->shadow_flags = 0;
#ifdef CONFIG_HVM
@@ -734,7 +734,7 @@ void shadow_demote(struct domain *d, mfn_t gmfn, u32 type)
{
struct page_info *page = mfn_to_page(gmfn);

- ASSERT(test_bit(_PGC_page_table, &page->count_info));
+ ASSERT(test_bit(_PGC_shadowed_pt, &page->count_info));
ASSERT(page->shadow_flags & (1u << type));

page->shadow_flags &= ~(1u << type);
@@ -748,7 +748,7 @@ void shadow_demote(struct domain *d, mfn_t gmfn, u32 type)
oos_hash_remove(d, gmfn);
}
#endif
- clear_bit(_PGC_page_table, &page->count_info);
+ clear_bit(_PGC_shadowed_pt, &page->count_info);
}

TRACE_SHADOW_PATH_FLAG(TRCE_SFLAG_DEMOTE);
@@ -779,7 +779,7 @@ sh_validate_guest_entry(struct vcpu *v, mfn_t gmfn, void *entry, u32 size)
// Ditto for L2s before L3s, etc.
//

- if ( !(page->count_info & PGC_page_table) )
+ if ( !(page->count_info & PGC_shadowed_pt) )
return 0; /* Not shadowed at all */

if ( page->shadow_flags & SHF_L1_32 )
@@ -2266,7 +2266,7 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int fast, int all)
SHADOW_PRINTK("d%d gmfn=%"PRI_mfn"\n", d->domain_id, mfn_x(gmfn));

/* Bail out now if the page is not shadowed */
- if ( (pg->count_info & PGC_page_table) == 0 )
+ if ( !(pg->count_info & PGC_shadowed_pt) )
{
paging_unlock(d);
return;
@@ -2283,7 +2283,7 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int fast, int all)
*/
#define DO_UNSHADOW(_type) do { \
t = (_type); \
- if ( !(pg->count_info & PGC_page_table) || \
+ if ( !(pg->count_info & PGC_shadowed_pt) || \
!(pg->shadow_flags & (1 << t)) ) \
break; \
smfn = shadow_hash_lookup(d, mfn_x(gmfn), t); \
@@ -2299,7 +2299,7 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int fast, int all)
else if ( sh_type_has_up_pointer(d, t) ) \
sh_remove_shadow_via_pointer(d, smfn); \
if ( !fast && \
- (pg->count_info & PGC_page_table) && \
+ (pg->count_info & PGC_shadowed_pt) && \
(pg->shadow_flags & (1 << t)) ) \
{ \
HASH_CALLBACKS_CHECK(SHF_page_type_mask); \
@@ -2322,7 +2322,7 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int fast, int all)
#undef DO_UNSHADOW

/* If that didn't catch the shadows, something is wrong */
- if ( !fast && all && (pg->count_info & PGC_page_table) )
+ if ( !fast && all && (pg->count_info & PGC_shadowed_pt) )
{
printk(XENLOG_G_ERR "can't find all shadows of mfn %"PRI_mfn
" (shadow_flags=%04x)\n", mfn_x(gmfn), pg->shadow_flags);
@@ -2339,7 +2339,7 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int fast, int all)
void shadow_prepare_page_type_change(struct domain *d,
const struct page_info *page)
{
- if ( !(page->count_info & PGC_page_table) )
+ if ( !(page->count_info & PGC_shadowed_pt) )
return;

#if (SHADOW_OPTIMIZATIONS & SHOPT_OUT_OF_SYNC)
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h
index 85bb26c7ea..b8a62ec1ff 100644
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -320,7 +320,7 @@ static inline void sh_terminate_list(struct page_list_head *tmp_list)
static inline int sh_page_has_multiple_shadows(struct page_info *pg)
{
u32 shadows;
- if ( !(pg->count_info & PGC_page_table) )
+ if ( !(pg->count_info & PGC_shadowed_pt) )
return 0;
shadows = pg->shadow_flags & SHF_page_type_mask;
/* More than one type bit set in shadow-flags? */
@@ -332,7 +332,7 @@ static inline int sh_page_has_multiple_shadows(struct page_info *pg)
* domain is translated, &c */
static inline int page_is_out_of_sync(struct page_info *p)
{
- return (p->count_info & PGC_page_table)
+ return (p->count_info & PGC_shadowed_pt)
&& (p->shadow_flags & SHF_out_of_sync);
}

@@ -343,7 +343,7 @@ static inline int mfn_is_out_of_sync(mfn_t gmfn)

static inline int page_oos_may_write(struct page_info *p)
{
- return (p->count_info & PGC_page_table)
+ return (p->count_info & PGC_shadowed_pt)
&& (p->shadow_flags & SHF_oos_may_write);
}

@@ -545,7 +545,7 @@ sh_mfn_is_a_page_table(mfn_t gmfn)

owner = page_get_owner(page);
if ( owner && shadow_mode_refcounts(owner)
- && (page->count_info & PGC_page_table) )
+ && (page->count_info & PGC_shadowed_pt) )
return 1;

type_info = page->u.inuse.type_info & PGT_type_mask;
--
generated by git-patchbot for /home/xen/git/xen.git#master