Re: [PATCH 1/2] x86/mem_sharing: copy cpuid during vm forking

From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Tamas K Lengyel <tamas.lengyel@intel.com>,
	<xen-devel@lists.xenproject.org>
Cc: "Tamas K Lengyel" <tamas@tklengyel.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>
Subject: Re: [PATCH 1/2] x86/mem_sharing: copy cpuid during vm forking
Date: Tue, 5 Jan 2021 11:04:35 +0000	[thread overview]
Message-ID: <7cfa7763-e905-58a0-d4c6-2cca0a54b1ad@citrix.com> (raw)
In-Reply-To: <6d5ca8a57a2745e933f00706bff306844611f64d.1609781242.git.tamas.lengyel@intel.com>

On 04/01/2021 17:41, Tamas K Lengyel wrote:
> Signed-off-by: Tamas K Lengyel <tamas.lengyel@intel.com>
> ---
>  xen/arch/x86/mm/mem_sharing.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
> index c428fd16ce..4a02c7d6f2 100644
> --- a/xen/arch/x86/mm/mem_sharing.c
> +++ b/xen/arch/x86/mm/mem_sharing.c
> @@ -1764,6 +1764,7 @@ static int fork(struct domain *cd, struct domain *d)
>  
>          domain_pause(d);
>          cd->max_pages = d->max_pages;
> +        memcpy(cd->arch.cpuid, d->arch.cpuid, sizeof(*d->arch.cpuid));
>          cd->parent = d;
>      }
>  

You need to extend this to d->arch.msr and v->arch.msrs or someone is
going to have a very subtle bug to debug in the future.

~Andrew