From: Olaf Hering <olaf@aepfle.de>
To: xen-devel@lists.xensource.com
Subject: [PATCH 12/17] xenpaging: handle HVMCOPY_gfn_paged_out in copy_from/to_user
Date: Mon, 06 Dec 2010 21:59:19 +0100 [thread overview]
Message-ID: <20101206205912.343173055@aepfle.de> (raw)
In-Reply-To: 20101206205907.848643876@aepfle.de
[-- Attachment #1: xen-unstable.xenpaging.HVMCOPY_gfn_paged_out.patch --]
[-- Type: text/plain, Size: 7100 bytes --]
copy_from_user_hvm can fail when __hvm_copy returns
HVMCOPY_gfn_paged_out for a referenced gfn, for example during guests
pagetable walk. This has to be handled in some way.
Use the recently added wait_queue feature to preempt the current vcpu
when populate a page, then resume execution later when the page was
resumed. This is only done if the active domain needs to access the
page, because in this case the vcpu would leave the active state anyway.
This patch adds a return code to p2m_mem_paging_populate() to indicate
the caller that the page was ready, so it can retry the gfn_to_mfn call.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
xen/arch/x86/hvm/hvm.c | 3 ++-
xen/arch/x86/mm/guest_walk.c | 5 +++--
xen/arch/x86/mm/hap/guest_walk.c | 10 ++++++----
xen/arch/x86/mm/p2m.c | 19 ++++++++++++++-----
xen/common/domain.c | 1 +
xen/include/asm-x86/p2m.h | 7 ++++---
xen/include/xen/sched.h | 3 +++
7 files changed, 33 insertions(+), 15 deletions(-)
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/hvm/hvm.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/hvm/hvm.c
@@ -1939,7 +1939,8 @@ static enum hvm_copy_result __hvm_copy(
if ( p2m_is_paging(p2mt) )
{
- p2m_mem_paging_populate(p2m, gfn);
+ if ( p2m_mem_paging_populate(p2m, gfn) )
+ continue;
return HVMCOPY_gfn_paged_out;
}
if ( p2m_is_shared(p2mt) )
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/guest_walk.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/guest_walk.c
@@ -93,11 +93,12 @@ static inline void *map_domain_gfn(struc
uint32_t *rc)
{
/* Translate the gfn, unsharing if shared */
+retry:
*mfn = gfn_to_mfn_unshare(p2m, gfn_x(gfn), p2mt, 0);
if ( p2m_is_paging(*p2mt) )
{
- p2m_mem_paging_populate(p2m, gfn_x(gfn));
-
+ if ( p2m_mem_paging_populate(p2m, gfn_x(gfn)) )
+ goto retry;
*rc = _PAGE_PAGED;
return NULL;
}
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/hap/guest_walk.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/hap/guest_walk.c
@@ -46,12 +46,13 @@ unsigned long hap_gva_to_gfn(GUEST_PAGIN
struct p2m_domain *p2m = p2m_get_hostp2m(v->domain);
/* Get the top-level table's MFN */
+retry_cr3:
cr3 = v->arch.hvm_vcpu.guest_cr[3];
top_mfn = gfn_to_mfn_unshare(p2m, cr3 >> PAGE_SHIFT, &p2mt, 0);
if ( p2m_is_paging(p2mt) )
{
- p2m_mem_paging_populate(p2m, cr3 >> PAGE_SHIFT);
-
+ if ( p2m_mem_paging_populate(p2m, cr3 >> PAGE_SHIFT) )
+ goto retry_cr3;
pfec[0] = PFEC_page_paged;
return INVALID_GFN;
}
@@ -79,11 +80,12 @@ unsigned long hap_gva_to_gfn(GUEST_PAGIN
if ( missing == 0 )
{
gfn_t gfn = guest_l1e_get_gfn(gw.l1e);
+retry_missing:
gfn_to_mfn_unshare(p2m, gfn_x(gfn), &p2mt, 0);
if ( p2m_is_paging(p2mt) )
{
- p2m_mem_paging_populate(p2m, gfn_x(gfn));
-
+ if ( p2m_mem_paging_populate(p2m, gfn_x(gfn)) )
+ goto retry_missing;
pfec[0] = PFEC_page_paged;
return INVALID_GFN;
}
--- xen-unstable.hg-4.1.22459.orig/xen/arch/x86/mm/p2m.c
+++ xen-unstable.hg-4.1.22459/xen/arch/x86/mm/p2m.c
@@ -2777,16 +2777,17 @@ void p2m_mem_paging_drop_page(struct p2m
}
}
-void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn)
+int p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn)
{
struct vcpu *v = current;
mem_event_request_t req;
p2m_type_t p2mt;
struct domain *d = p2m->domain;
+ int ret = 0;
/* Check that there's space on the ring for this request */
if ( mem_event_check_ring(d, 1) )
- return;
+ return ret;
memset(&req, 0, sizeof(req));
@@ -2805,13 +2806,13 @@ void p2m_mem_paging_populate(struct p2m_
/* Pause domain */
if ( v->domain->domain_id == d->domain_id )
{
- vcpu_pause_nosync(v);
req.flags |= MEM_EVENT_FLAG_VCPU_PAUSED;
+ ret = 1;
}
else if ( p2mt != p2m_ram_paging_out && p2mt != p2m_ram_paged )
{
/* gfn is already on its way back and vcpu is not paused */
- return;
+ goto populate_out;
}
/* Send request to pager */
@@ -2820,6 +2821,14 @@ void p2m_mem_paging_populate(struct p2m_
req.vcpu_id = v->vcpu_id;
mem_event_put_request(d, &req);
+
+ if ( req.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
+ {
+ wait_event(d->wq, mfn_valid(gfn_to_mfn(p2m, gfn, &p2mt)) && !p2m_is_paging(p2mt));
+ }
+
+populate_out:
+ return ret;
}
int p2m_mem_paging_prep(struct p2m_domain *p2m, unsigned long gfn)
@@ -2863,7 +2872,7 @@ void p2m_mem_paging_resume(struct p2m_do
/* Unpause domain */
if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED )
- vcpu_unpause(d->vcpu[rsp.vcpu_id]);
+ wake_up(&d->wq);
/* Unpause any domains that were paused because the ring was full */
mem_event_unpause_vcpus(d);
--- xen-unstable.hg-4.1.22459.orig/xen/common/domain.c
+++ xen-unstable.hg-4.1.22459/xen/common/domain.c
@@ -244,6 +244,7 @@ struct domain *domain_create(
spin_lock_init(&d->node_affinity_lock);
spin_lock_init(&d->shutdown_lock);
+ init_waitqueue_head(&d->wq);
d->shutdown_code = -1;
if ( domcr_flags & DOMCRF_hvm )
--- xen-unstable.hg-4.1.22459.orig/xen/include/asm-x86/p2m.h
+++ xen-unstable.hg-4.1.22459/xen/include/asm-x86/p2m.h
@@ -474,7 +474,8 @@ int p2m_mem_paging_evict(struct p2m_doma
/* Tell xenpaging to drop a paged out frame */
void p2m_mem_paging_drop_page(struct p2m_domain *p2m, unsigned long gfn);
/* Start populating a paged out frame */
-void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn);
+/* retval 1 means the page is present on return */
+int p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn);
/* Prepare the p2m for paging a frame in */
int p2m_mem_paging_prep(struct p2m_domain *p2m, unsigned long gfn);
/* Resume normal operation (in case a domain was paused) */
@@ -482,8 +483,8 @@ void p2m_mem_paging_resume(struct p2m_do
#else
static inline void p2m_mem_paging_drop_page(struct p2m_domain *p2m, unsigned long gfn)
{ }
-static inline void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn)
-{ }
+static inline int p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn)
+{ return 0; }
#endif
struct page_info *p2m_alloc_ptp(struct p2m_domain *p2m, unsigned long type);
--- xen-unstable.hg-4.1.22459.orig/xen/include/xen/sched.h
+++ xen-unstable.hg-4.1.22459/xen/include/xen/sched.h
@@ -26,6 +26,7 @@
#include <xen/cpumask.h>
#include <xen/nodemask.h>
#include <xen/multicall.h>
+#include <xen/wait.h>
#ifdef CONFIG_COMPAT
#include <compat/vcpu.h>
@@ -332,6 +333,8 @@ struct domain
nodemask_t node_affinity;
unsigned int last_alloc_node;
spinlock_t node_affinity_lock;
+
+ struct waitqueue_head wq;
};
struct domain_setup_info
next prev parent reply other threads:[~2010-12-06 20:59 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-06 20:59 [PATCH 00/17] xenpaging changes for xen-unstable Olaf Hering
2010-12-06 20:59 ` [PATCH 01/17] xenpaging: close xch handle in xenpaging_init error path Olaf Hering
2010-12-14 18:52 ` Ian Jackson
2010-12-06 20:59 ` [PATCH 02/17] xenpaging: remove perror usage " Olaf Hering
2010-12-06 20:59 ` [PATCH 03/17] xenpaging: print DPRINTF ouput if XENPAGING_DEBUG is in environment Olaf Hering
2010-12-06 20:59 ` [PATCH 04/17] xenpaging: print number of evicted pages Olaf Hering
2010-12-06 20:59 ` [PATCH 05/17] xenpaging: remove duplicate xc_interface_close call Olaf Hering
2010-12-06 20:59 ` [PATCH 06/17] xenpaging: do not use DPRINTF/ERROR if xch handle is unavailable Olaf Hering
2010-12-06 20:59 ` [PATCH 07/17] xenpaging: update xch usage Olaf Hering
2010-12-06 20:59 ` [PATCH 08/17] xenpaging: make vcpu_sleep_nosync() optional in mem_event_check_ring() Olaf Hering
2010-12-06 20:59 ` [PATCH 09/17] xenpaging: update machine_to_phys_mapping[] during page deallocation Olaf Hering
2010-12-06 20:59 ` [PATCH 10/17] xenpaging: update machine_to_phys_mapping[] during page-in Olaf Hering
2010-12-14 22:58 ` Olaf Hering
2010-12-15 10:47 ` Tim Deegan
2010-12-06 20:59 ` [PATCH 11/17] xenpaging: drop paged pages in guest_remove_page Olaf Hering
2010-12-06 20:59 ` Olaf Hering [this message]
2010-12-07 9:27 ` [PATCH 12/17] xenpaging: handle HVMCOPY_gfn_paged_out in copy_from/to_user Jan Beulich
2010-12-07 9:45 ` Olaf Hering
2010-12-15 11:35 ` Keir Fraser
2010-12-15 13:51 ` Olaf Hering
2010-12-15 14:08 ` Keir Fraser
2010-12-06 20:59 ` [PATCH 13/17] xenpaging: page only pagetables for debugging Olaf Hering
2010-12-06 20:59 ` [PATCH 14/17] xenpaging: prevent page-out of first 16MB Olaf Hering
2010-12-06 20:59 ` [PATCH 15/17] xenpaging: start xenpaging via config option Olaf Hering
2010-12-06 20:59 ` [PATCH 16/17] xenpaging: add dynamic startup delay for xenpaging Olaf Hering
2010-12-06 20:59 ` [PATCH 17/17] xenpaging: (sparse) documenation Olaf Hering
2010-12-06 21:16 ` [PATCH 00/17] xenpaging changes for xen-unstable Olaf Hering
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