From e804d547bff0f7ce108e2bb9583f65770dc9744b Mon Sep 17 00:00:00 2001 From: Liu, Jinsong Date: Thu, 8 Nov 2012 09:09:19 +0800 Subject: [PATCH 2/2] Xen/acpi: revert pad config check in xen_check_mwait With Xen acpi pad logic added into kernel, we can now revert xen mwait related patch df88b2d96e36d9a9e325bfcd12eb45671cbbc937. The reason is, when running under newer Xen platform, Xen pad driver would be early loaded, so native pad driver would fail to be loaded, and hence no mwait/monitor #UD risk again. Another point is, only Xen4.2 or later support Xen acpi pad, so we won't expose mwait cpuid capability when running under older Xen platform. Signed-off-by: Liu, Jinsong --- arch/x86/xen/enlighten.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 586d838..548296f 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -287,8 +287,7 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx, static bool __init xen_check_mwait(void) { -#if defined(CONFIG_ACPI) && !defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) && \ - !defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE) +#ifdef CONFIG_ACPI struct xen_platform_op op = { .cmd = XENPF_set_processor_pminfo, .u.set_pminfo.id = -1, @@ -309,6 +308,13 @@ static bool __init xen_check_mwait(void) if (!xen_initial_domain()) return false; + /* + * When running under platform earlier than Xen4.2, do not expose + * mwait, to avoid the risk of loading native acpi pad driver + */ + if (!xen_running_on_version_or_later(4, 2)) + return false; + ax = 1; cx = 0; -- 1.7.1