On 12/16/2014 05:47 PM, H. Peter Anvin wrote:
On 12/16/2014 01:58 AM, Juergen Gross wrote:
VMWare seems not to emulate the PAT MSR correctly: reaeding
MSR_IA32_CR_PAT returns 0 even after writing another value to it.
Detect this bug and don't use the read value if it is 0.
Commit bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 ("x86: Enable PAT to
use cache mode translation tables") triggers this VMWare bug when the
kernel is booted as a VMWare guest.
Reported-by: Jongman Heo <jongman....@samsung.com>
Signed-off-by: Juergen Gross <jgr...@suse.com>
Tested-by: Jongman Heo <jongman....@samsung.com>
I presume cachability control is irrelevant for a VMware guest? I'm
wondering if it would be better to just plain ignore the failure rather
than disabling PAT.
I'd rather disable PAT as this seems to be like a PAT erratum.
In case you want to keep PAT active I can redo the patch to not rely on
the read MSR value in the non-Xen case (under Xen reading the MSR is the
only way to obtain the correct settings).
Juergen
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