Re: [Xen-devel] MSR IA32_MISC_ENABLE missing on AMD (OVMF use it now)

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 03/08/2017 10:59 AM, Anthony PERARD wrote:
> Hi,
>
> Recently, OVMF start to read MSR 0x1a0, which cause a General Protection
> fault on AMD, but not in Intel. OMVF does not handle it and crash.

I don't think this MSR exists on AMD processors so that would be OVMF bug.

-boris

>
> OVMF use msr 0x1a0, which seems to be IA32_MISC_ENABLE, to find out if
> the XD attribute can be use on page tables.
>
> From a recent run (OVMF output):
> http://logs.test-lab.xenproject.org/osstest/logs/106538/test-amd64-amd64-xl-qemuu-ovmf-amd64/rimava0---var-log-xen-osstest-serial-debianhvm.guest.osstest.log
>
> This is where the read is made:
> https://github.com/tianocore/edk2/blob/master/UefiCpuPkg/CpuDxe/CpuPageTable.c#L196
>
> It was first introduced in this commit:
> "UefiCpuPkg/CpuDxe: Add memory attribute setting."
> https://github.com/tianocore/edk2/commit/22292ed344b8512c838bdd162533198b51a51c0c
>
> Is this a missing feature in Xen or a bug in OVMF?
>
> Regards,
>


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