linux-kernel - Re: [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: <5566D320.50009@huawei.com>
Date:	Thu, 28 May 2015 16:34:40 +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: Re: [RESEND PATCH] xen: vcpu_info would be reset to wrong place on
 canceled suspend on PVOPS VM which has multi-cpu

Hi all,

It's been a long time, I don't know whether this patch is OK or not. Or does it somewhere need to be improved a little bit?

thanks

On 2015.5.6 9:47, Ouyang Zhaowei (Charles) wrote:
> 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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