From e3aa4e61b57da7574fdd1b4c9ca9bdee06a4d23e Mon Sep 17 00:00:00 2001 From: "Liu, Jinsong" Date: Thu, 8 Nov 2012 05:44:28 +0000 Subject: [PATCH] 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 ("xen/enlighten: Disable MWAIT_LEAF so that acpi-pad won't be loaded. "). 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 Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/enlighten.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index a90c3bb58bed..eb0edff5499b 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; -- 2.30.2