Re: [Xen-devel] [V5 PATCH 1/1] x86/xen: Set EFER.NX and EFER.SCE in PVH guests

From: David Vrabel
Date: Fri Sep 26 2014 - 13:26:45 EST


On 11/09/14 00:36, Mukesh Rathor wrote:
> This fixes two bugs in PVH guests:
>
> - Not setting EFER.NX means the NX bit in page table entries is
> ignored on Intel processors and causes reserved bit page faults on
> AMD processors.
>
> - After the Xen commit 7645640d6ff1 ("x86/PVH: don't set EFER_SCE for
> pvh guest") PVH guests are required to set EFER.SCE to enable the
> SYSCALL instruction.
>
> Secondary VCPUs are started with pagetables with the NX bit set so
> EFER.NX must be set before using any stack or data segment.
> xen_pvh_cpu_early_init() is the new secondary VCPU entry point that
> sets EFER before jumping to cpu_bringup_and_idle().

Applied to devel/for-linus-3.18

Thanks.

David
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