Messages in this thread | | | Date | Mon, 27 Nov 2023 16:06:13 +0100 | Subject | Re: [PATCH] x86/xen: fix percpu vcpu_info allocation | From | Juergen Gross <> |
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On 27.11.23 16:00, Jan Beulich wrote: > On 27.11.2023 15:57, Boris Ostrovsky wrote: >> >> >> On 11/24/23 2:48 AM, 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> >> >> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.con> >> >> although I am not sure in usefulness of BUILD_BUG_ON --- 64 bytes is part of ABI and hypervisor already has its own BUILD_BUG_ON for this. > > I understood the check to guard against SMP_CACHE_BYTES < 64.
Yes, that was the idea. Better safe than sorry.
Juergen [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |