* [PATCH v5] xen/grant-table: Avoid m2p_override during mapping
@ 2014-01-23 13:07 Zoltan Kiss
2014-01-24 14:37 ` [Xen-devel] " Konrad Rzeszutek Wilk
0 siblings, 1 reply; 4+ messages in thread
From: Zoltan Kiss @ 2014-01-23 13:07 UTC (permalink / raw)
To: ian.campbell, wei.liu2, xen-devel, netdev, linux-kernel, jonathan.davies
Cc: Zoltan Kiss
The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
for blkback and future netback patches it just cause a lock contention, as
those pages never go to userspace. Therefore this series does the following:
- the original functions were renamed to __gnttab_[un]map_refs, with a new
parameter m2p_override
- based on m2p_override either they follow the original behaviour, or just set
the private flag and call set_phys_to_machine
- gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
m2p_override false
- a new function gnttab_[un]map_refs_userspace provides the old behaviour
It also removes a stray space from page.h and change ret to 0 if
XENFEAT_auto_translated_physmap, as that is the only possible return value
there.
v2:
- move the storing of the old mfn in page->index to gnttab_map_refs
- move the function header update to a separate patch
v3:
- a new approach to retain old behaviour where it needed
- squash the patches into one
v4:
- move out the common bits from m2p* functions, and pass pfn/mfn as parameter
- clear page->private before doing anything with the page, so m2p_find_override
won't race with this
v5:
- change return value handling in __gnttab_[un]map_refs
- remove a stray space in page.h
- add detail why ret = 0 now at some places
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Suggested-by: David Vrabel <david.vrabel@citrix.com>
---
arch/x86/include/asm/xen/page.h | 12 +++--
arch/x86/xen/p2m.c | 25 ++--------
drivers/block/xen-blkback/blkback.c | 15 +++---
drivers/xen/gntdev.c | 13 +++--
drivers/xen/grant-table.c | 90 ++++++++++++++++++++++++++++++-----
include/xen/grant_table.h | 8 +++-
6 files changed, 109 insertions(+), 54 deletions(-)
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index b913915..68a1438 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -49,10 +49,14 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
extern unsigned long set_phys_range_identity(unsigned long pfn_s,
unsigned long pfn_e);
-extern int m2p_add_override(unsigned long mfn, struct page *page,
- struct gnttab_map_grant_ref *kmap_op);
+extern int m2p_add_override(unsigned long mfn,
+ struct page *page,
+ struct gnttab_map_grant_ref *kmap_op,
+ unsigned long pfn);
extern int m2p_remove_override(struct page *page,
- struct gnttab_map_grant_ref *kmap_op);
+ struct gnttab_map_grant_ref *kmap_op,
+ unsigned long pfn,
+ unsigned long mfn);
extern struct page *m2p_find_override(unsigned long mfn);
extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
@@ -121,7 +125,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
pfn = m2p_find_override_pfn(mfn, ~0);
}
- /*
+ /*
* pfn is ~0 if there are no entries in the m2p for mfn or if the
* entry doesn't map back to the mfn and m2p_override doesn't have a
* valid entry for it.
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 2ae8699..0060178 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -872,15 +872,13 @@ static unsigned long mfn_hash(unsigned long mfn)
/* Add an MFN override for a particular page */
int m2p_add_override(unsigned long mfn, struct page *page,
- struct gnttab_map_grant_ref *kmap_op)
+ struct gnttab_map_grant_ref *kmap_op, unsigned long pfn)
{
unsigned long flags;
- unsigned long pfn;
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
- pfn = page_to_pfn(page);
if (!PageHighMem(page)) {
address = (unsigned long)__va(pfn << PAGE_SHIFT);
ptep = lookup_address(address, &level);
@@ -888,13 +886,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
"m2p_add_override: pfn %lx not mapped", pfn))
return -EINVAL;
}
- WARN_ON(PagePrivate(page));
- SetPagePrivate(page);
- set_page_private(page, mfn);
- page->index = pfn_to_mfn(pfn);
-
- if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
- return -ENOMEM;
if (kmap_op != NULL) {
if (!PageHighMem(page)) {
@@ -933,20 +924,15 @@ int m2p_add_override(unsigned long mfn, struct page *page,
}
EXPORT_SYMBOL_GPL(m2p_add_override);
int m2p_remove_override(struct page *page,
- struct gnttab_map_grant_ref *kmap_op)
+ struct gnttab_map_grant_ref *kmap_op,
+ unsigned long pfn,
+ unsigned long mfn)
{
unsigned long flags;
- unsigned long mfn;
- unsigned long pfn;
unsigned long uninitialized_var(address);
unsigned level;
pte_t *ptep = NULL;
- pfn = page_to_pfn(page);
- mfn = get_phys_to_machine(pfn);
- if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
- return -EINVAL;
-
if (!PageHighMem(page)) {
address = (unsigned long)__va(pfn << PAGE_SHIFT);
ptep = lookup_address(address, &level);
@@ -959,10 +945,7 @@ int m2p_remove_override(struct page *page,
spin_lock_irqsave(&m2p_override_lock, flags);
list_del(&page->lru);
spin_unlock_irqrestore(&m2p_override_lock, flags);
- WARN_ON(!PagePrivate(page));
- ClearPagePrivate(page);
- set_phys_to_machine(pfn, page->index);
if (kmap_op != NULL) {
if (!PageHighMem(page)) {
struct multicall_space mcs;
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 6620b73..875025f 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
!rb_next(&persistent_gnt->node)) {
- ret = gnttab_unmap_refs(unmap, NULL, pages,
- segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
segs_to_unmap = 0;
@@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work)
pages[segs_to_unmap] = persistent_gnt->page;
if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
- ret = gnttab_unmap_refs(unmap, NULL, pages,
- segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
segs_to_unmap = 0;
@@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work)
kfree(persistent_gnt);
}
if (segs_to_unmap > 0) {
- ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
}
@@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
GNTMAP_host_map, pages[i]->handle);
pages[i]->handle = BLKBACK_INVALID_HANDLE;
if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
- ret = gnttab_unmap_refs(unmap, NULL, unmap_pages,
- invcount);
+ ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
BUG_ON(ret);
put_free_pages(blkif, unmap_pages, invcount);
invcount = 0;
}
}
if (invcount) {
- ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
+ ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
BUG_ON(ret);
put_free_pages(blkif, unmap_pages, invcount);
}
@@ -740,7 +737,7 @@ again:
}
if (segs_to_map) {
- ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
+ ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
BUG_ON(ret);
}
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index e41c79c..e652c0e 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map)
}
pr_debug("map %d+%d\n", map->index, map->count);
- err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
- map->pages, map->count);
+ err = gnttab_map_refs_userspace(map->map_ops,
+ use_ptemod ? map->kmap_ops : NULL,
+ map->pages,
+ map->count);
if (err)
return err;
@@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
}
}
- err = gnttab_unmap_refs(map->unmap_ops + offset,
- use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
- pages);
+ err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
+ use_ptemod ? map->kmap_ops + offset : NULL,
+ map->pages + offset,
+ pages);
if (err)
return err;
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index aa846a4..2add483 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -880,15 +880,17 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
}
EXPORT_SYMBOL_GPL(gnttab_batch_copy);
-int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
- struct page **pages, unsigned int count)
+ struct page **pages, unsigned int count,
+ bool m2p_override)
{
int i, ret;
bool lazy = false;
pte_t *pte;
- unsigned long mfn;
+ unsigned long mfn, pfn;
+ BUG_ON(kmap_ops && !m2p_override);
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
if (ret)
return ret;
@@ -907,10 +909,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
map_ops[i].dev_bus_addr >> PAGE_SHIFT);
}
- return ret;
+ return 0;
}
- if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+ if (m2p_override &&
+ !in_interrupt() &&
+ paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
arch_enter_lazy_mmu_mode();
lazy = true;
}
@@ -927,8 +931,20 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
} else {
mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
}
- ret = m2p_add_override(mfn, pages[i], kmap_ops ?
- &kmap_ops[i] : NULL);
+ pfn = page_to_pfn(pages[i]);
+
+ WARN_ON(PagePrivate(pages[i]));
+ SetPagePrivate(pages[i]);
+ set_page_private(pages[i], mfn);
+
+ pages[i]->index = pfn_to_mfn(pfn);
+ if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ if (m2p_override)
+ ret = m2p_add_override(mfn, pages[i], kmap_ops ?
+ &kmap_ops[i] : NULL, pfn);
if (ret)
goto out;
}
@@ -939,15 +955,32 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
return ret;
}
+
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+ struct page **pages, unsigned int count)
+{
+ return __gnttab_map_refs(map_ops, NULL, pages, count, false);
+}
EXPORT_SYMBOL_GPL(gnttab_map_refs);
-int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
+ struct gnttab_map_grant_ref *kmap_ops,
+ struct page **pages, unsigned int count)
+{
+ return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true);
+}
+EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace);
+
+int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
struct gnttab_map_grant_ref *kmap_ops,
- struct page **pages, unsigned int count)
+ struct page **pages, unsigned int count,
+ bool m2p_override)
{
int i, ret;
bool lazy = false;
+ unsigned long pfn, mfn;
+ BUG_ON(kmap_ops && !m2p_override);
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
if (ret)
return ret;
@@ -958,17 +991,34 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
INVALID_P2M_ENTRY);
}
- return ret;
+ return 0;
}
- if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
+ if (m2p_override &&
+ !in_interrupt() &&
+ paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
arch_enter_lazy_mmu_mode();
lazy = true;
}
for (i = 0; i < count; i++) {
- ret = m2p_remove_override(pages[i], kmap_ops ?
- &kmap_ops[i] : NULL);
+ pfn = page_to_pfn(pages[i]);
+ mfn = get_phys_to_machine(pfn);
+ if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ set_page_private(pages[i], INVALID_P2M_ENTRY);
+ WARN_ON(!PagePrivate(pages[i]));
+ ClearPagePrivate(pages[i]);
+ set_phys_to_machine(pfn, pages[i]->index);
+ if (m2p_override)
+ ret = m2p_remove_override(pages[i],
+ kmap_ops ?
+ &kmap_ops[i] : NULL,
+ pfn,
+ mfn);
if (ret)
goto out;
}
@@ -979,8 +1029,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
return ret;
}
+
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops,
+ struct page **pages, unsigned int count)
+{
+ return __gnttab_unmap_refs(map_ops, NULL, pages, count, false);
+}
EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
+int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops,
+ struct gnttab_map_grant_ref *kmap_ops,
+ struct page **pages, unsigned int count)
+{
+ return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true);
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace);
+
static unsigned nr_status_frames(unsigned nr_grant_frames)
{
BUG_ON(grefs_per_grant_frame == 0);
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 694dcaf..9a919b1 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -184,11 +184,15 @@ unsigned int gnttab_max_grant_frames(void);
#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
- struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count);
+int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
+ struct gnttab_map_grant_ref *kmap_ops,
+ struct page **pages, unsigned int count);
int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
- struct gnttab_map_grant_ref *kunmap_ops,
struct page **pages, unsigned int count);
+int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops,
+ struct gnttab_map_grant_ref *kunmap_ops,
+ struct page **pages, unsigned int count);
/* Perform a batch of grant map/copy operations. Retry every batch slot
* for which the hypervisor returns GNTST_eagain. This is typically due
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Xen-devel] [PATCH v5] xen/grant-table: Avoid m2p_override during mapping
2014-01-23 13:07 [PATCH v5] xen/grant-table: Avoid m2p_override during mapping Zoltan Kiss
@ 2014-01-24 14:37 ` Konrad Rzeszutek Wilk
2014-01-24 14:44 ` David Vrabel
2014-01-24 14:48 ` Stefano Stabellini
0 siblings, 2 replies; 4+ messages in thread
From: Konrad Rzeszutek Wilk @ 2014-01-24 14:37 UTC (permalink / raw)
To: Zoltan Kiss, Stefano Stabellini, david.vrabel, boris.ostrovsky
Cc: ian.campbell, wei.liu2, xen-devel, netdev, linux-kernel, jonathan.davies
On Thu, Jan 23, 2014 at 01:07:10PM +0000, Zoltan Kiss wrote:
> The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
> for blkback and future netback patches it just cause a lock contention, as
> those pages never go to userspace. Therefore this series does the following:
> - the original functions were renamed to __gnttab_[un]map_refs, with a new
> parameter m2p_override
> - based on m2p_override either they follow the original behaviour, or just set
> the private flag and call set_phys_to_machine
> - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
> m2p_override false
> - a new function gnttab_[un]map_refs_userspace provides the old behaviour
>
> It also removes a stray space from page.h and change ret to 0 if
> XENFEAT_auto_translated_physmap, as that is the only possible return value
> there.
>
> v2:
> - move the storing of the old mfn in page->index to gnttab_map_refs
> - move the function header update to a separate patch
>
> v3:
> - a new approach to retain old behaviour where it needed
> - squash the patches into one
>
> v4:
> - move out the common bits from m2p* functions, and pass pfn/mfn as parameter
> - clear page->private before doing anything with the page, so m2p_find_override
> won't race with this
>
> v5:
> - change return value handling in __gnttab_[un]map_refs
> - remove a stray space in page.h
> - add detail why ret = 0 now at some places
>
> Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
> Suggested-by: David Vrabel <david.vrabel@citrix.com>
It looks OK to me and while it is not a bug-fix I think it should
go for v3.14 - as it _should_ improve the backends.
David or Boris; Stefano, please Ack/Nack it.
Thank you.
> ---
> arch/x86/include/asm/xen/page.h | 12 +++--
> arch/x86/xen/p2m.c | 25 ++--------
> drivers/block/xen-blkback/blkback.c | 15 +++---
> drivers/xen/gntdev.c | 13 +++--
> drivers/xen/grant-table.c | 90 ++++++++++++++++++++++++++++++-----
> include/xen/grant_table.h | 8 +++-
> 6 files changed, 109 insertions(+), 54 deletions(-)
>
> diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> index b913915..68a1438 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -49,10 +49,14 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
> extern unsigned long set_phys_range_identity(unsigned long pfn_s,
> unsigned long pfn_e);
>
> -extern int m2p_add_override(unsigned long mfn, struct page *page,
> - struct gnttab_map_grant_ref *kmap_op);
> +extern int m2p_add_override(unsigned long mfn,
> + struct page *page,
> + struct gnttab_map_grant_ref *kmap_op,
> + unsigned long pfn);
> extern int m2p_remove_override(struct page *page,
> - struct gnttab_map_grant_ref *kmap_op);
> + struct gnttab_map_grant_ref *kmap_op,
> + unsigned long pfn,
> + unsigned long mfn);
> extern struct page *m2p_find_override(unsigned long mfn);
> extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
>
> @@ -121,7 +125,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
> pfn = m2p_find_override_pfn(mfn, ~0);
> }
>
> - /*
> + /*
> * pfn is ~0 if there are no entries in the m2p for mfn or if the
> * entry doesn't map back to the mfn and m2p_override doesn't have a
> * valid entry for it.
> diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> index 2ae8699..0060178 100644
> --- a/arch/x86/xen/p2m.c
> +++ b/arch/x86/xen/p2m.c
> @@ -872,15 +872,13 @@ static unsigned long mfn_hash(unsigned long mfn)
>
> /* Add an MFN override for a particular page */
> int m2p_add_override(unsigned long mfn, struct page *page,
> - struct gnttab_map_grant_ref *kmap_op)
> + struct gnttab_map_grant_ref *kmap_op, unsigned long pfn)
> {
> unsigned long flags;
> - unsigned long pfn;
> unsigned long uninitialized_var(address);
> unsigned level;
> pte_t *ptep = NULL;
>
> - pfn = page_to_pfn(page);
> if (!PageHighMem(page)) {
> address = (unsigned long)__va(pfn << PAGE_SHIFT);
> ptep = lookup_address(address, &level);
> @@ -888,13 +886,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
> "m2p_add_override: pfn %lx not mapped", pfn))
> return -EINVAL;
> }
> - WARN_ON(PagePrivate(page));
> - SetPagePrivate(page);
> - set_page_private(page, mfn);
> - page->index = pfn_to_mfn(pfn);
> -
> - if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
> - return -ENOMEM;
>
> if (kmap_op != NULL) {
> if (!PageHighMem(page)) {
> @@ -933,20 +924,15 @@ int m2p_add_override(unsigned long mfn, struct page *page,
> }
> EXPORT_SYMBOL_GPL(m2p_add_override);
> int m2p_remove_override(struct page *page,
> - struct gnttab_map_grant_ref *kmap_op)
> + struct gnttab_map_grant_ref *kmap_op,
> + unsigned long pfn,
> + unsigned long mfn)
> {
> unsigned long flags;
> - unsigned long mfn;
> - unsigned long pfn;
> unsigned long uninitialized_var(address);
> unsigned level;
> pte_t *ptep = NULL;
>
> - pfn = page_to_pfn(page);
> - mfn = get_phys_to_machine(pfn);
> - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
> - return -EINVAL;
> -
> if (!PageHighMem(page)) {
> address = (unsigned long)__va(pfn << PAGE_SHIFT);
> ptep = lookup_address(address, &level);
> @@ -959,10 +945,7 @@ int m2p_remove_override(struct page *page,
> spin_lock_irqsave(&m2p_override_lock, flags);
> list_del(&page->lru);
> spin_unlock_irqrestore(&m2p_override_lock, flags);
> - WARN_ON(!PagePrivate(page));
> - ClearPagePrivate(page);
>
> - set_phys_to_machine(pfn, page->index);
> if (kmap_op != NULL) {
> if (!PageHighMem(page)) {
> struct multicall_space mcs;
> diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> index 6620b73..875025f 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
>
> if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
> !rb_next(&persistent_gnt->node)) {
> - ret = gnttab_unmap_refs(unmap, NULL, pages,
> - segs_to_unmap);
> + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> BUG_ON(ret);
> put_free_pages(blkif, pages, segs_to_unmap);
> segs_to_unmap = 0;
> @@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work)
> pages[segs_to_unmap] = persistent_gnt->page;
>
> if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
> - ret = gnttab_unmap_refs(unmap, NULL, pages,
> - segs_to_unmap);
> + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> BUG_ON(ret);
> put_free_pages(blkif, pages, segs_to_unmap);
> segs_to_unmap = 0;
> @@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work)
> kfree(persistent_gnt);
> }
> if (segs_to_unmap > 0) {
> - ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
> + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> BUG_ON(ret);
> put_free_pages(blkif, pages, segs_to_unmap);
> }
> @@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
> GNTMAP_host_map, pages[i]->handle);
> pages[i]->handle = BLKBACK_INVALID_HANDLE;
> if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
> - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages,
> - invcount);
> + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
> BUG_ON(ret);
> put_free_pages(blkif, unmap_pages, invcount);
> invcount = 0;
> }
> }
> if (invcount) {
> - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
> + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
> BUG_ON(ret);
> put_free_pages(blkif, unmap_pages, invcount);
> }
> @@ -740,7 +737,7 @@ again:
> }
>
> if (segs_to_map) {
> - ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
> + ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
> BUG_ON(ret);
> }
>
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index e41c79c..e652c0e 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map)
> }
>
> pr_debug("map %d+%d\n", map->index, map->count);
> - err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
> - map->pages, map->count);
> + err = gnttab_map_refs_userspace(map->map_ops,
> + use_ptemod ? map->kmap_ops : NULL,
> + map->pages,
> + map->count);
> if (err)
> return err;
>
> @@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
> }
> }
>
> - err = gnttab_unmap_refs(map->unmap_ops + offset,
> - use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
> - pages);
> + err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
> + use_ptemod ? map->kmap_ops + offset : NULL,
> + map->pages + offset,
> + pages);
> if (err)
> return err;
>
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index aa846a4..2add483 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -880,15 +880,17 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
> }
> EXPORT_SYMBOL_GPL(gnttab_batch_copy);
>
> -int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> +int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> struct gnttab_map_grant_ref *kmap_ops,
> - struct page **pages, unsigned int count)
> + struct page **pages, unsigned int count,
> + bool m2p_override)
> {
> int i, ret;
> bool lazy = false;
> pte_t *pte;
> - unsigned long mfn;
> + unsigned long mfn, pfn;
>
> + BUG_ON(kmap_ops && !m2p_override);
> ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
> if (ret)
> return ret;
> @@ -907,10 +909,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
> map_ops[i].dev_bus_addr >> PAGE_SHIFT);
> }
> - return ret;
> + return 0;
> }
>
> - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> + if (m2p_override &&
> + !in_interrupt() &&
> + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> arch_enter_lazy_mmu_mode();
> lazy = true;
> }
> @@ -927,8 +931,20 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> } else {
> mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
> }
> - ret = m2p_add_override(mfn, pages[i], kmap_ops ?
> - &kmap_ops[i] : NULL);
> + pfn = page_to_pfn(pages[i]);
> +
> + WARN_ON(PagePrivate(pages[i]));
> + SetPagePrivate(pages[i]);
> + set_page_private(pages[i], mfn);
> +
> + pages[i]->index = pfn_to_mfn(pfn);
> + if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
> + ret = -ENOMEM;
> + goto out;
> + }
> + if (m2p_override)
> + ret = m2p_add_override(mfn, pages[i], kmap_ops ?
> + &kmap_ops[i] : NULL, pfn);
> if (ret)
> goto out;
> }
> @@ -939,15 +955,32 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
>
> return ret;
> }
> +
> +int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> + struct page **pages, unsigned int count)
> +{
> + return __gnttab_map_refs(map_ops, NULL, pages, count, false);
> +}
> EXPORT_SYMBOL_GPL(gnttab_map_refs);
>
> -int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
> + struct gnttab_map_grant_ref *kmap_ops,
> + struct page **pages, unsigned int count)
> +{
> + return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true);
> +}
> +EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace);
> +
> +int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> struct gnttab_map_grant_ref *kmap_ops,
> - struct page **pages, unsigned int count)
> + struct page **pages, unsigned int count,
> + bool m2p_override)
> {
> int i, ret;
> bool lazy = false;
> + unsigned long pfn, mfn;
>
> + BUG_ON(kmap_ops && !m2p_override);
> ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
> if (ret)
> return ret;
> @@ -958,17 +991,34 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
> INVALID_P2M_ENTRY);
> }
> - return ret;
> + return 0;
> }
>
> - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> + if (m2p_override &&
> + !in_interrupt() &&
> + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> arch_enter_lazy_mmu_mode();
> lazy = true;
> }
>
> for (i = 0; i < count; i++) {
> - ret = m2p_remove_override(pages[i], kmap_ops ?
> - &kmap_ops[i] : NULL);
> + pfn = page_to_pfn(pages[i]);
> + mfn = get_phys_to_machine(pfn);
> + if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + set_page_private(pages[i], INVALID_P2M_ENTRY);
> + WARN_ON(!PagePrivate(pages[i]));
> + ClearPagePrivate(pages[i]);
> + set_phys_to_machine(pfn, pages[i]->index);
> + if (m2p_override)
> + ret = m2p_remove_override(pages[i],
> + kmap_ops ?
> + &kmap_ops[i] : NULL,
> + pfn,
> + mfn);
> if (ret)
> goto out;
> }
> @@ -979,8 +1029,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
>
> return ret;
> }
> +
> +int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops,
> + struct page **pages, unsigned int count)
> +{
> + return __gnttab_unmap_refs(map_ops, NULL, pages, count, false);
> +}
> EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
>
> +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops,
> + struct gnttab_map_grant_ref *kmap_ops,
> + struct page **pages, unsigned int count)
> +{
> + return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true);
> +}
> +EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace);
> +
> static unsigned nr_status_frames(unsigned nr_grant_frames)
> {
> BUG_ON(grefs_per_grant_frame == 0);
> diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
> index 694dcaf..9a919b1 100644
> --- a/include/xen/grant_table.h
> +++ b/include/xen/grant_table.h
> @@ -184,11 +184,15 @@ unsigned int gnttab_max_grant_frames(void);
> #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
>
> int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> - struct gnttab_map_grant_ref *kmap_ops,
> struct page **pages, unsigned int count);
> +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
> + struct gnttab_map_grant_ref *kmap_ops,
> + struct page **pages, unsigned int count);
> int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> - struct gnttab_map_grant_ref *kunmap_ops,
> struct page **pages, unsigned int count);
> +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops,
> + struct gnttab_map_grant_ref *kunmap_ops,
> + struct page **pages, unsigned int count);
>
> /* Perform a batch of grant map/copy operations. Retry every batch slot
> * for which the hypervisor returns GNTST_eagain. This is typically due
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xen-devel] [PATCH v5] xen/grant-table: Avoid m2p_override during mapping
2014-01-24 14:37 ` [Xen-devel] " Konrad Rzeszutek Wilk
@ 2014-01-24 14:44 ` David Vrabel
2014-01-24 14:48 ` Stefano Stabellini
1 sibling, 0 replies; 4+ messages in thread
From: David Vrabel @ 2014-01-24 14:44 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Zoltan Kiss, Stefano Stabellini, boris.ostrovsky, ian.campbell,
wei.liu2, xen-devel, netdev, linux-kernel, jonathan.davies
On 24/01/14 14:37, Konrad Rzeszutek Wilk wrote:
> On Thu, Jan 23, 2014 at 01:07:10PM +0000, Zoltan Kiss wrote:
>> The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
>> for blkback and future netback patches it just cause a lock contention, as
>> those pages never go to userspace. Therefore this series does the following:
>> - the original functions were renamed to __gnttab_[un]map_refs, with a new
>> parameter m2p_override
>> - based on m2p_override either they follow the original behaviour, or just set
>> the private flag and call set_phys_to_machine
>> - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
>> m2p_override false
>> - a new function gnttab_[un]map_refs_userspace provides the old behaviour
>>
>> It also removes a stray space from page.h and change ret to 0 if
>> XENFEAT_auto_translated_physmap, as that is the only possible return value
>> there.
>>
>> v2:
>> - move the storing of the old mfn in page->index to gnttab_map_refs
>> - move the function header update to a separate patch
>>
>> v3:
>> - a new approach to retain old behaviour where it needed
>> - squash the patches into one
>>
>> v4:
>> - move out the common bits from m2p* functions, and pass pfn/mfn as parameter
>> - clear page->private before doing anything with the page, so m2p_find_override
>> won't race with this
>>
>> v5:
>> - change return value handling in __gnttab_[un]map_refs
>> - remove a stray space in page.h
>> - add detail why ret = 0 now at some places
>>
>> Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
>> Suggested-by: David Vrabel <david.vrabel@citrix.com>
>
> It looks OK to me and while it is not a bug-fix I think it should
> go for v3.14 - as it _should_ improve the backends.
>
> David or Boris; Stefano, please Ack/Nack it.
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
David
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xen-devel] [PATCH v5] xen/grant-table: Avoid m2p_override during mapping
2014-01-24 14:37 ` [Xen-devel] " Konrad Rzeszutek Wilk
2014-01-24 14:44 ` David Vrabel
@ 2014-01-24 14:48 ` Stefano Stabellini
1 sibling, 0 replies; 4+ messages in thread
From: Stefano Stabellini @ 2014-01-24 14:48 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Zoltan Kiss, Stefano Stabellini, david.vrabel, boris.ostrovsky,
ian.campbell, wei.liu2, xen-devel, netdev, linux-kernel,
jonathan.davies
On Fri, 24 Jan 2014, Konrad Rzeszutek Wilk wrote:
> On Thu, Jan 23, 2014 at 01:07:10PM +0000, Zoltan Kiss wrote:
> > The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
> > for blkback and future netback patches it just cause a lock contention, as
> > those pages never go to userspace. Therefore this series does the following:
> > - the original functions were renamed to __gnttab_[un]map_refs, with a new
> > parameter m2p_override
> > - based on m2p_override either they follow the original behaviour, or just set
> > the private flag and call set_phys_to_machine
> > - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
> > m2p_override false
> > - a new function gnttab_[un]map_refs_userspace provides the old behaviour
> >
> > It also removes a stray space from page.h and change ret to 0 if
> > XENFEAT_auto_translated_physmap, as that is the only possible return value
> > there.
> >
> > v2:
> > - move the storing of the old mfn in page->index to gnttab_map_refs
> > - move the function header update to a separate patch
> >
> > v3:
> > - a new approach to retain old behaviour where it needed
> > - squash the patches into one
> >
> > v4:
> > - move out the common bits from m2p* functions, and pass pfn/mfn as parameter
> > - clear page->private before doing anything with the page, so m2p_find_override
> > won't race with this
> >
> > v5:
> > - change return value handling in __gnttab_[un]map_refs
> > - remove a stray space in page.h
> > - add detail why ret = 0 now at some places
> >
> > Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
> > Suggested-by: David Vrabel <david.vrabel@citrix.com>
>
> It looks OK to me and while it is not a bug-fix I think it should
> go for v3.14 - as it _should_ improve the backends.
>
> David or Boris; Stefano, please Ack/Nack it.
>
> Thank you.
I reviewed-by the v6 version of the patch
> > arch/x86/include/asm/xen/page.h | 12 +++--
> > arch/x86/xen/p2m.c | 25 ++--------
> > drivers/block/xen-blkback/blkback.c | 15 +++---
> > drivers/xen/gntdev.c | 13 +++--
> > drivers/xen/grant-table.c | 90 ++++++++++++++++++++++++++++++-----
> > include/xen/grant_table.h | 8 +++-
> > 6 files changed, 109 insertions(+), 54 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> > index b913915..68a1438 100644
> > --- a/arch/x86/include/asm/xen/page.h
> > +++ b/arch/x86/include/asm/xen/page.h
> > @@ -49,10 +49,14 @@ extern bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
> > extern unsigned long set_phys_range_identity(unsigned long pfn_s,
> > unsigned long pfn_e);
> >
> > -extern int m2p_add_override(unsigned long mfn, struct page *page,
> > - struct gnttab_map_grant_ref *kmap_op);
> > +extern int m2p_add_override(unsigned long mfn,
> > + struct page *page,
> > + struct gnttab_map_grant_ref *kmap_op,
> > + unsigned long pfn);
> > extern int m2p_remove_override(struct page *page,
> > - struct gnttab_map_grant_ref *kmap_op);
> > + struct gnttab_map_grant_ref *kmap_op,
> > + unsigned long pfn,
> > + unsigned long mfn);
> > extern struct page *m2p_find_override(unsigned long mfn);
> > extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
> >
> > @@ -121,7 +125,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
> > pfn = m2p_find_override_pfn(mfn, ~0);
> > }
> >
> > - /*
> > + /*
> > * pfn is ~0 if there are no entries in the m2p for mfn or if the
> > * entry doesn't map back to the mfn and m2p_override doesn't have a
> > * valid entry for it.
> > diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> > index 2ae8699..0060178 100644
> > --- a/arch/x86/xen/p2m.c
> > +++ b/arch/x86/xen/p2m.c
> > @@ -872,15 +872,13 @@ static unsigned long mfn_hash(unsigned long mfn)
> >
> > /* Add an MFN override for a particular page */
> > int m2p_add_override(unsigned long mfn, struct page *page,
> > - struct gnttab_map_grant_ref *kmap_op)
> > + struct gnttab_map_grant_ref *kmap_op, unsigned long pfn)
> > {
> > unsigned long flags;
> > - unsigned long pfn;
> > unsigned long uninitialized_var(address);
> > unsigned level;
> > pte_t *ptep = NULL;
> >
> > - pfn = page_to_pfn(page);
> > if (!PageHighMem(page)) {
> > address = (unsigned long)__va(pfn << PAGE_SHIFT);
> > ptep = lookup_address(address, &level);
> > @@ -888,13 +886,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
> > "m2p_add_override: pfn %lx not mapped", pfn))
> > return -EINVAL;
> > }
> > - WARN_ON(PagePrivate(page));
> > - SetPagePrivate(page);
> > - set_page_private(page, mfn);
> > - page->index = pfn_to_mfn(pfn);
> > -
> > - if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
> > - return -ENOMEM;
> >
> > if (kmap_op != NULL) {
> > if (!PageHighMem(page)) {
> > @@ -933,20 +924,15 @@ int m2p_add_override(unsigned long mfn, struct page *page,
> > }
> > EXPORT_SYMBOL_GPL(m2p_add_override);
> > int m2p_remove_override(struct page *page,
> > - struct gnttab_map_grant_ref *kmap_op)
> > + struct gnttab_map_grant_ref *kmap_op,
> > + unsigned long pfn,
> > + unsigned long mfn)
> > {
> > unsigned long flags;
> > - unsigned long mfn;
> > - unsigned long pfn;
> > unsigned long uninitialized_var(address);
> > unsigned level;
> > pte_t *ptep = NULL;
> >
> > - pfn = page_to_pfn(page);
> > - mfn = get_phys_to_machine(pfn);
> > - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
> > - return -EINVAL;
> > -
> > if (!PageHighMem(page)) {
> > address = (unsigned long)__va(pfn << PAGE_SHIFT);
> > ptep = lookup_address(address, &level);
> > @@ -959,10 +945,7 @@ int m2p_remove_override(struct page *page,
> > spin_lock_irqsave(&m2p_override_lock, flags);
> > list_del(&page->lru);
> > spin_unlock_irqrestore(&m2p_override_lock, flags);
> > - WARN_ON(!PagePrivate(page));
> > - ClearPagePrivate(page);
> >
> > - set_phys_to_machine(pfn, page->index);
> > if (kmap_op != NULL) {
> > if (!PageHighMem(page)) {
> > struct multicall_space mcs;
> > diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> > index 6620b73..875025f 100644
> > --- a/drivers/block/xen-blkback/blkback.c
> > +++ b/drivers/block/xen-blkback/blkback.c
> > @@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
> >
> > if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
> > !rb_next(&persistent_gnt->node)) {
> > - ret = gnttab_unmap_refs(unmap, NULL, pages,
> > - segs_to_unmap);
> > + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> > BUG_ON(ret);
> > put_free_pages(blkif, pages, segs_to_unmap);
> > segs_to_unmap = 0;
> > @@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work)
> > pages[segs_to_unmap] = persistent_gnt->page;
> >
> > if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
> > - ret = gnttab_unmap_refs(unmap, NULL, pages,
> > - segs_to_unmap);
> > + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> > BUG_ON(ret);
> > put_free_pages(blkif, pages, segs_to_unmap);
> > segs_to_unmap = 0;
> > @@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work)
> > kfree(persistent_gnt);
> > }
> > if (segs_to_unmap > 0) {
> > - ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
> > + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
> > BUG_ON(ret);
> > put_free_pages(blkif, pages, segs_to_unmap);
> > }
> > @@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
> > GNTMAP_host_map, pages[i]->handle);
> > pages[i]->handle = BLKBACK_INVALID_HANDLE;
> > if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
> > - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages,
> > - invcount);
> > + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
> > BUG_ON(ret);
> > put_free_pages(blkif, unmap_pages, invcount);
> > invcount = 0;
> > }
> > }
> > if (invcount) {
> > - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
> > + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount);
> > BUG_ON(ret);
> > put_free_pages(blkif, unmap_pages, invcount);
> > }
> > @@ -740,7 +737,7 @@ again:
> > }
> >
> > if (segs_to_map) {
> > - ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
> > + ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
> > BUG_ON(ret);
> > }
> >
> > diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> > index e41c79c..e652c0e 100644
> > --- a/drivers/xen/gntdev.c
> > +++ b/drivers/xen/gntdev.c
> > @@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map)
> > }
> >
> > pr_debug("map %d+%d\n", map->index, map->count);
> > - err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
> > - map->pages, map->count);
> > + err = gnttab_map_refs_userspace(map->map_ops,
> > + use_ptemod ? map->kmap_ops : NULL,
> > + map->pages,
> > + map->count);
> > if (err)
> > return err;
> >
> > @@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
> > }
> > }
> >
> > - err = gnttab_unmap_refs(map->unmap_ops + offset,
> > - use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
> > - pages);
> > + err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
> > + use_ptemod ? map->kmap_ops + offset : NULL,
> > + map->pages + offset,
> > + pages);
> > if (err)
> > return err;
> >
> > diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> > index aa846a4..2add483 100644
> > --- a/drivers/xen/grant-table.c
> > +++ b/drivers/xen/grant-table.c
> > @@ -880,15 +880,17 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count)
> > }
> > EXPORT_SYMBOL_GPL(gnttab_batch_copy);
> >
> > -int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > +int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > struct gnttab_map_grant_ref *kmap_ops,
> > - struct page **pages, unsigned int count)
> > + struct page **pages, unsigned int count,
> > + bool m2p_override)
> > {
> > int i, ret;
> > bool lazy = false;
> > pte_t *pte;
> > - unsigned long mfn;
> > + unsigned long mfn, pfn;
> >
> > + BUG_ON(kmap_ops && !m2p_override);
> > ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
> > if (ret)
> > return ret;
> > @@ -907,10 +909,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
> > map_ops[i].dev_bus_addr >> PAGE_SHIFT);
> > }
> > - return ret;
> > + return 0;
> > }
> >
> > - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> > + if (m2p_override &&
> > + !in_interrupt() &&
> > + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> > arch_enter_lazy_mmu_mode();
> > lazy = true;
> > }
> > @@ -927,8 +931,20 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > } else {
> > mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
> > }
> > - ret = m2p_add_override(mfn, pages[i], kmap_ops ?
> > - &kmap_ops[i] : NULL);
> > + pfn = page_to_pfn(pages[i]);
> > +
> > + WARN_ON(PagePrivate(pages[i]));
> > + SetPagePrivate(pages[i]);
> > + set_page_private(pages[i], mfn);
> > +
> > + pages[i]->index = pfn_to_mfn(pfn);
> > + if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {
> > + ret = -ENOMEM;
> > + goto out;
> > + }
> > + if (m2p_override)
> > + ret = m2p_add_override(mfn, pages[i], kmap_ops ?
> > + &kmap_ops[i] : NULL, pfn);
> > if (ret)
> > goto out;
> > }
> > @@ -939,15 +955,32 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> >
> > return ret;
> > }
> > +
> > +int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > + struct page **pages, unsigned int count)
> > +{
> > + return __gnttab_map_refs(map_ops, NULL, pages, count, false);
> > +}
> > EXPORT_SYMBOL_GPL(gnttab_map_refs);
> >
> > -int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> > +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
> > + struct gnttab_map_grant_ref *kmap_ops,
> > + struct page **pages, unsigned int count)
> > +{
> > + return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true);
> > +}
> > +EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace);
> > +
> > +int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> > struct gnttab_map_grant_ref *kmap_ops,
> > - struct page **pages, unsigned int count)
> > + struct page **pages, unsigned int count,
> > + bool m2p_override)
> > {
> > int i, ret;
> > bool lazy = false;
> > + unsigned long pfn, mfn;
> >
> > + BUG_ON(kmap_ops && !m2p_override);
> > ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
> > if (ret)
> > return ret;
> > @@ -958,17 +991,34 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> > set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT,
> > INVALID_P2M_ENTRY);
> > }
> > - return ret;
> > + return 0;
> > }
> >
> > - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> > + if (m2p_override &&
> > + !in_interrupt() &&
> > + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> > arch_enter_lazy_mmu_mode();
> > lazy = true;
> > }
> >
> > for (i = 0; i < count; i++) {
> > - ret = m2p_remove_override(pages[i], kmap_ops ?
> > - &kmap_ops[i] : NULL);
> > + pfn = page_to_pfn(pages[i]);
> > + mfn = get_phys_to_machine(pfn);
> > + if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
> > + ret = -EINVAL;
> > + goto out;
> > + }
> > +
> > + set_page_private(pages[i], INVALID_P2M_ENTRY);
> > + WARN_ON(!PagePrivate(pages[i]));
> > + ClearPagePrivate(pages[i]);
> > + set_phys_to_machine(pfn, pages[i]->index);
> > + if (m2p_override)
> > + ret = m2p_remove_override(pages[i],
> > + kmap_ops ?
> > + &kmap_ops[i] : NULL,
> > + pfn,
> > + mfn);
> > if (ret)
> > goto out;
> > }
> > @@ -979,8 +1029,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> >
> > return ret;
> > }
> > +
> > +int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops,
> > + struct page **pages, unsigned int count)
> > +{
> > + return __gnttab_unmap_refs(map_ops, NULL, pages, count, false);
> > +}
> > EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
> >
> > +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops,
> > + struct gnttab_map_grant_ref *kmap_ops,
> > + struct page **pages, unsigned int count)
> > +{
> > + return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true);
> > +}
> > +EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace);
> > +
> > static unsigned nr_status_frames(unsigned nr_grant_frames)
> > {
> > BUG_ON(grefs_per_grant_frame == 0);
> > diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
> > index 694dcaf..9a919b1 100644
> > --- a/include/xen/grant_table.h
> > +++ b/include/xen/grant_table.h
> > @@ -184,11 +184,15 @@ unsigned int gnttab_max_grant_frames(void);
> > #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
> >
> > int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
> > - struct gnttab_map_grant_ref *kmap_ops,
> > struct page **pages, unsigned int count);
> > +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops,
> > + struct gnttab_map_grant_ref *kmap_ops,
> > + struct page **pages, unsigned int count);
> > int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
> > - struct gnttab_map_grant_ref *kunmap_ops,
> > struct page **pages, unsigned int count);
> > +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *unmap_ops,
> > + struct gnttab_map_grant_ref *kunmap_ops,
> > + struct page **pages, unsigned int count);
> >
> > /* Perform a batch of grant map/copy operations. Retry every batch slot
> > * for which the hypervisor returns GNTST_eagain. This is typically due
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-01-24 14:48 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-01-23 13:07 [PATCH v5] xen/grant-table: Avoid m2p_override during mapping Zoltan Kiss
2014-01-24 14:37 ` [Xen-devel] " Konrad Rzeszutek Wilk
2014-01-24 14:44 ` David Vrabel
2014-01-24 14:48 ` Stefano Stabellini
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