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Date: Tue, 2 Oct 2018 14:27:25 +0100
From: Anthony PERARD <anthony.perard@citrix.com>
To: <marcandre.lureau@redhat.com>
CC: <edk2-devel@lists.01.org>, Jordan Justen <jordan.l.justen@intel.com>,
 Laszlo Ersek <lersek@redhat.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, 
 Julien Grall <julien.grall@linaro.org>
Message-ID: <20181002132725.GA1331@perard.uk.xensource.com>
References: <20181002121725.17178-1-marcandre.lureau@redhat.com>
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Subject: Re: [PATCH v3 1/1] OvmfPkg/PlatformPei: clear CPU caches
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On Tue, Oct 02, 2018 at 04:17:25PM +0400, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> This is for conformance with the TCG "Platform Reset Attack Mitigation
> Specification". Because clearing the CPU caches at boot doesn't impact
> performance significantly, do it unconditionally, for simplicity's
> sake.
> 
> Flush the cache on all logical processors, thanks to
> EFI_PEI_MP_SERVICES_PPI and CacheMaintenanceLib.
> 
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Anthony Perard <anthony.perard@citrix.com>
> Cc: Julien Grall <julien.grall@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

That patch works for me on Xen. I can still boot guests with the patch
applied, with either 1 or 4 vcpus assigned to the guest:

Tested-by: Anthony PERARD <anthony.perard@citrix.com>

Thanks,

-- 
Anthony PERARD