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From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Juergen Gross <jgross@suse.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH] x86/xen: fix percpu vcpu_info allocation
Date: Tue, 28 Nov 2023 12:06:41 +0100	[thread overview]
Message-ID: <ZWXJwf4K4FOWSmK5@macbook> (raw)
In-Reply-To: <20231124074852.25161-1-jgross@suse.com>

On Fri, Nov 24, 2023 at 08:48:52AM +0100, Juergen Gross wrote:
> Today the percpu struct vcpu_info is allocated via DEFINE_PER_CPU(),
> meaning that it could cross a page boundary. In this case registering
> it with the hypervisor will fail, resulting in a panic().
> 
> This can easily be fixed by using DEFINE_PER_CPU_ALIGNED() instead,
> as struct vcpu_info is guaranteed to have a size of 64 bytes, matching
> the cache line size of x86 64-bit processors (Xen doesn't support
> 32-bit processors).
> 
> Fixes: 5ead97c84fa7 ("xen: Core Xen implementation")
> Signed-off-by: Juergen Gross <jgross@suse.com>

FWIW, on FreeBSD we also switched to the same approach quite
recently:

https://cgit.freebsd.org/src/commit/sys/xen/xen_common.c?id=20fc5bf7df1db698f2651eaa04a3bc71290e1636

Should have checked the Linux side, sorry.

Roger.

      parent reply	other threads:[~2023-11-28 11:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-24  7:48 [PATCH] x86/xen: fix percpu vcpu_info allocation Juergen Gross
2023-11-27 14:57 ` Boris Ostrovsky
2023-11-27 15:00   ` Jan Beulich
2023-11-27 15:06     ` Juergen Gross
2023-11-28 11:06 ` Roger Pau Monné [this message]

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