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Date: Thu, 21 Aug 2014 21:39:04 -0400 From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> To: Mukesh Rathor <mukesh.rathor@...cle.com> Cc: boris.ostrovsky@...cle.com, david.vrabel@...rix.com, xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org Subject: Re: [Xen-devel] [V0 PATCH 1/2] AMD-PVH: set EFER.NX and EFER.SCE for the boot vcpu On Wed, Aug 20, 2014 at 07:16:39PM -0700, Mukesh Rathor wrote: > On AMD, NX feature must be enabled in the efer for NX to be honored in > the pte entries, otherwise protection fault. We also set SC for > system calls to be enabled. How come we don't need to do that for Intel (that is set the NX bit)? Could you include the explanation here please? > > Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com> > --- > arch/x86/xen/enlighten.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c > index c0cb11f..4af512d 100644 > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -1499,6 +1499,17 @@ void __ref xen_pvh_secondary_vcpu_init(int cpu) > xen_pvh_set_cr_flags(cpu); > } > > +/* This is done in secondary_startup_64 for hvm guests. */ > +static void __init xen_configure_efer(void) > +{ > + u64 efer; > + > + rdmsrl(MSR_EFER, efer); > + efer |= EFER_SCE; > + efer |= (cpuid_edx(0x80000001) & (1 << 20)) ? EFER_NX : 0; Ahem? #defines for these magic values please? Or could you use 'boot_cpu_has'? > + wrmsrl(MSR_EFER, efer); > +} > + > static void __init xen_pvh_early_guest_init(void) > { > if (!xen_feature(XENFEAT_auto_translated_physmap)) > @@ -1508,6 +1519,7 @@ static void __init xen_pvh_early_guest_init(void) > return; > > xen_have_vector_callback = 1; > + xen_configure_efer(); > xen_pvh_set_cr_flags(0); > > #ifdef CONFIG_X86_32 > -- > 1.8.3.1 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@...ts.xen.org > http://lists.xen.org/xen-devel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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