From: Tamas K Lengyel <tamas@tklengyel.com>
To: xen-devel@lists.xenproject.org
Cc: "Petre Pircalabu" <ppircalabu@bitdefender.com>,
"Tamas K Lengyel" <tamas@tklengyel.com>,
"Julien Grall" <julien@xen.org>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Jan Beulich" <jbeulich@suse.com>,
"Alexandru Isaila" <aisaila@bitdefender.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH 2/3] xen/vm_event: add vm_event_check_pending_op
Date: Fri, 15 May 2020 10:53:01 -0600 [thread overview]
Message-ID: <0b282dc0a59459da4db0c53b13508e1ff39d70b9.1589561218.git.tamas@tklengyel.com> (raw)
In-Reply-To: <cover.1589561218.git.tamas@tklengyel.com>
Perform sanity checking when shutting vm_event down to determine whether
it is safe to do so. Error out with -EAGAIN in case pending operations
have been found for the domain.
Signed-off-by: Tamas K Lengyel <tamas@tklengyel.com>
---
xen/arch/x86/vm_event.c | 23 +++++++++++++++++++++++
xen/common/vm_event.c | 17 ++++++++++++++---
xen/include/asm-arm/vm_event.h | 7 +++++++
xen/include/asm-x86/vm_event.h | 2 ++
4 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/vm_event.c b/xen/arch/x86/vm_event.c
index 848d69c1b0..558b7da4b1 100644
--- a/xen/arch/x86/vm_event.c
+++ b/xen/arch/x86/vm_event.c
@@ -297,6 +297,29 @@ void vm_event_emulate_check(struct vcpu *v, vm_event_response_t *rsp)
};
}
+bool vm_event_check_pending_op(struct vcpu *v)
+{
+ struct monitor_write_data *w = &v->arch.vm_event->write_data;
+
+ if ( !v->arch.vm_event->sync_event )
+ return false;
+
+ if ( w->do_write.cr0 )
+ return true;
+ if ( w->do_write.cr3 )
+ return true;
+ if ( w->do_write.cr4 )
+ return true;
+ if ( w->do_write.msr )
+ return true;
+ if ( v->arch.vm_event->set_gprs )
+ return true;
+ if ( v->arch.vm_event->emulate_flags )
+ return true;
+
+ return false;
+}
+
/*
* Local variables:
* mode: C
diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c
index 127f2d58f1..2df327a42c 100644
--- a/xen/common/vm_event.c
+++ b/xen/common/vm_event.c
@@ -183,6 +183,7 @@ static int vm_event_disable(struct domain *d, struct vm_event_domain **p_ved)
if ( vm_event_check_ring(ved) )
{
struct vcpu *v;
+ bool pending_op = false;
spin_lock(&ved->lock);
@@ -192,9 +193,6 @@ static int vm_event_disable(struct domain *d, struct vm_event_domain **p_ved)
return -EBUSY;
}
- /* Free domU's event channel and leave the other one unbound */
- free_xen_event_channel(d, ved->xen_port);
-
/* Unblock all vCPUs */
for_each_vcpu ( d, v )
{
@@ -203,8 +201,21 @@ static int vm_event_disable(struct domain *d, struct vm_event_domain **p_ved)
vcpu_unpause(v);
ved->blocked--;
}
+
+ if ( vm_event_check_pending_op(v) )
+ pending_op = true;
}
+ /* vm_event ops are still pending until vCPUs get scheduled */
+ if ( pending_op )
+ {
+ spin_unlock(&ved->lock);
+ return -EAGAIN;
+ }
+
+ /* Free domU's event channel and leave the other one unbound */
+ free_xen_event_channel(d, ved->xen_port);
+
destroy_ring_for_helper(&ved->ring_page, ved->ring_pg_struct);
vm_event_cleanup_domain(d);
diff --git a/xen/include/asm-arm/vm_event.h b/xen/include/asm-arm/vm_event.h
index 14d1d341cc..5cbc9c6dc2 100644
--- a/xen/include/asm-arm/vm_event.h
+++ b/xen/include/asm-arm/vm_event.h
@@ -58,4 +58,11 @@ void vm_event_sync_event(struct vcpu *v, bool value)
/* Not supported on ARM. */
}
+static inline
+bool vm_event_check_pending_op(struct vcpu *v)
+{
+ /* Not supported on ARM. */
+ return false;
+}
+
#endif /* __ASM_ARM_VM_EVENT_H__ */
diff --git a/xen/include/asm-x86/vm_event.h b/xen/include/asm-x86/vm_event.h
index 785e741fba..9c5ce3129c 100644
--- a/xen/include/asm-x86/vm_event.h
+++ b/xen/include/asm-x86/vm_event.h
@@ -54,4 +54,6 @@ void vm_event_emulate_check(struct vcpu *v, vm_event_response_t *rsp);
void vm_event_sync_event(struct vcpu *v, bool value);
+bool vm_event_check_pending_op(struct vcpu *v);
+
#endif /* __ASM_X86_VM_EVENT_H__ */
--
2.26.1
next prev parent reply other threads:[~2020-05-15 16:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 16:52 [PATCH 0/3] vm_event: fix race-condition when disabling monitor events Tamas K Lengyel
2020-05-15 16:53 ` [PATCH 1/3] xen/monitor: Control register values Tamas K Lengyel
2020-05-20 13:36 ` Jan Beulich
2020-05-20 13:42 ` Tamas K Lengyel
2020-05-20 13:48 ` Jan Beulich
2020-05-21 1:28 ` Tamas K Lengyel
2020-05-15 16:53 ` Tamas K Lengyel [this message]
2020-05-15 16:53 ` [PATCH 3/3] xen/vm_event: Add safe to disable vm_event Tamas K Lengyel
2020-05-20 13:45 ` Jan Beulich
2020-05-20 15:27 ` Tamas K Lengyel
2020-05-21 2:18 ` Tamas K Lengyel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0b282dc0a59459da4db0c53b13508e1ff39d70b9.1589561218.git.tamas@tklengyel.com \
--to=tamas@tklengyel.com \
--cc=Volodymyr_Babchuk@epam.com \
--cc=aisaila@bitdefender.com \
--cc=andrew.cooper3@citrix.com \
--cc=jbeulich@suse.com \
--cc=julien@xen.org \
--cc=ppircalabu@bitdefender.com \
--cc=roger.pau@citrix.com \
--cc=sstabellini@kernel.org \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.