linux-kernel - [RESEND PATCH] xen: vcpu_info would be reset to wrong place on canceled suspend on PVOPS VM which has multi-cpu

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Message-ID: <55497298.4070307@huawei.com>
Date:	Wed, 6 May 2015 09:47:04 +0800
From:	"Ouyang Zhaowei (Charles)" <ouyangzhaowei@...wei.com>
To:	David Vrabel <david.vrabel@...rix.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC:	<linux-kernel@...r.kernel.org>,
	Dingweiping <weiping.ding@...wei.com>,
	Yanqiangjun <yanqiangjun@...wei.com>, <jinjian@...wei.com>
Subject: [RESEND PATCH] xen: vcpu_info would be reset to wrong place on canceled
 suspend on PVOPS VM which has multi-cpu

vcpu_info would be reset to wrong place on canceled suspend on PVOPS VM which has multi-cpu

The hypervisor continues assuming that vcpu_info is stored in per-cpu data which was set up by xen_vcpu_setup(),
while on canceled suspend, the call to xen_hvm_init_shared_info() will make the guest think that vcpu_info
is in the shared page. This will cause non-boot cpus keep checking a wrong vcpu_info address and can not handle
irqs any more after suspend canceled, for example after we do "xl save -c/restore", PVOPS VM can not be resumed
as the cpus can not finish their irqs.


Signed-off-by: Charles Ouyang <ouyangzhaowei@...wei.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Reviewed-by: David Vrabel <david.vrabel@...rix.com>
---
 arch/x86/xen/suspend.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index d949769..b2bed45 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -32,7 +32,8 @@ static void xen_hvm_post_suspend(int suspend_cancelled)
 {
 #ifdef CONFIG_XEN_PVHVM
        int cpu;
-       xen_hvm_init_shared_info();
+       if (!suspend_cancelled)
+               xen_hvm_init_shared_info();
        xen_callback_vector();
        xen_unplug_emulated_devices();
        if (xen_feature(XENFEAT_hvm_safe_pvclock)) {

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